Streamflow Observations

Posted by: Seina

Streamflow Observations - 27/04/2010 12:05

Streamflow Lowest in Memory…More than 20 years.

Streamflow Onkaparinga River March 2010.
Posted by: Seina

Re: Streamflow Observations - 09/05/2010 13:15

Summary of Observations

The level of the water table (level of groundwater in the absence of pressure) for this area in the Mount Lofty Ranges (MLR) appears to be at the bottom of the local river. Judging from the lack of rain in recent months, the Onkaparinga River does not appear to be perennial. It seems more ephemeral, meaning it only flows when there are significant rains, and that it has a stop-start nature. Although there are signs of spring activity further upstream, it does not appear to be enough to sustain continuous flows. I suspect that as low-pressure systems (or more specifically, significant pre-frontal pressure gradients) approach that this may cause upstream spring flows to increase gradually. This would probably require additional research into MSLP observations for the area. Depending on the water content of the soil and aquifers beneath, this atmospheric-surface water-groundwater system may act like more dynamically, like a sponge rather than a rigid structure, responding to various dynamic fluxes. It also seems that changes in sub-surface groundwater pressure result it changes in detention rates (rate of transfer of moisture between groundwater and surface systems), wherein the moisture entering the soil is not the same moisture leaving the sub-surface saturated zone and groundwater aquifers. This seems fairly straightforward reasoning, and also suggests that fluxes in groundwater pressure due to soil and sub-surface structural properties (soil type) are highly dependent on atmospheric input, as the evident ephemeral nature of the Onkaparinga River seems to imply. That said the Onkaparinga River appears to be a losing stream, meaning it does not retain as much moisture as it receives. Interestingly, this may mean it is possible for both losing and gaining streams to be located within the same catchment region.

The rainfall in these parts also appears to reflect in the nature of the local river’s behaviour. Most rain falls in short periods, over a localised area, with differences in rainfall over as little as half a kilometre. When the soil in floodplain areas is very dry, there appears to be a greater potential for flooding as moisture does not have enough time to infiltrate the soil if the rate of rainfall is too great (recent summer downpours indicate that perhaps only 14-18 mm in an hour). This lack of infiltrating may also be influenced by the dryness of the soil in that there is a disconnect between the hydrologic flow of sub-surface moisture and surface water, which in turn would be dependent on the pressure between pores with and without water content. This would no doubt affect the dynamics and responses of the groundwater to surface water systems, as the sponge characterisation of soil moisture absorption comes into effect.

The actual stream flow appears to be very dependent on the rate of detention of moisture from aquifers deep underground. Once a threshold is reached, it only takes a few millimetres for there to be stream flow (quick flow). And provided rain continues for long enough, it will only take a few millimetres over hours for the stream’s volume to begin increasing rapidly – exponentially in nature. This rapid increase in stream flow is likely also assisted by surface-pressure changes – a general region-wide drop in atmospheric pressure, which would take the pressure off underground aquifers (again a sponge-like effect) and lead to more moisture being able to approach the surface. During heavy rains this is the likely characteristic behaviour of an artesian spring, in which water gushes from the surface. Added to these effects, as rain continues to fall, there is a counter balance to the effects of low surface pressures, and more rain leads to more pressure to sub-surface detention rates, and more stream flow.

Again interestingly, the microclimate of the area, involving ground cover (grass) and trees, appears to add to micro scale rainfall effects. Significant evaporation and transpiration from plants and soil surface adds to the moisture already passing through or stagnant in the region (probably 5-15 mm per day in the summer, and maybe 2-3 during rainfall). This drop in evaporation and transpiration appears to be inversely related to rainfall, and thus stream flow. Possibly, too much humidity near the surface means this moisture remains stagnant, as more clouds prevent the energy needed for converting water to vapour from reaching the surface.

The typical water retention and osmotic potential of plants in the area is probably around 0.3, meaning 30% of surface-water (including evaporation) is retained in plants on average throughout the year. This surface layer of moisture or humidity extends up to 30 metres vertically along the river where the density of trees is high. Added to this humidity effect, which increases the precipitable water in the near-surface atmosphere (especially during rain and thunderstorms) is the observed micro climate effect of rain leading to more rain when the precipitable water experiences a downward pressure due to super-saturated conditions, which the 30% osmotic effect contributes to. As a note of benefit, precipitable water is dependent on both the MSLP and vapour pressure, so atmospheric pressure and water vapour changes in the atmosphere above the Onkaparinga’s riparian environment (and within it) are likely to have some measurable influence on river flows.

All in all, the effects of microclimatic conditions on the Onkaparinga River (and the rainfall which leads to stream flow) appear to be quite pronounced. The big question mark is over sub-surface moisture retention, and, quantitatively, how much is down there. The indications are there is a lot more sub-surface water than surface water.
Posted by: Seina

Re: Streamflow Observations - 11/05/2010 15:48

Comparisons of Stream flow discharge (volume/height):

Peak Flow, Winter 2009

This image is a bit blurry probably partly due to the weather conditions, and also because the river could have breached its blanks (I was in a rush):

“IDS20364
AUSTRALIAN GOVERNMENT - BUREAU OF METEOROLOGY
SOUTH AUSTRALIA REGIONAL OFFICE

WARNING FOR MINOR FLOODING
For the Upper Onkaparinga River
Issued at 5:30 pm on Monday, 24 August 2009

1. FLOOD WARNING :
Heavy rainfall has been recorded in the upper Onkaparinga catchment during the
last six hours. This has resulted in rapid rises in the upper Onkaparinga River
and tributaries.

Minor flood levels are expected to be reached during the next hour [by 6:30 pm]
in Lenswood Creek at Lenswood, Inverbrackie Creek at the gauging station and in
the Onkaparinga River at Oakbank Ford.

River levels in the Onkaparinga River downstream at Verdun are not expected to
exceed the minor flood level at this stage.

Rainfall is forecast to ease to showers early this evening, and further rises
beyond minor flood levels are not anticipated.

People are advised to keep away from floodwaters.
Motorists are advised to avoid low level road crossings.

For information, contact the State Emergency Service 132 500

2. RAINFALL AND RIVER HEIGHT OBSERVATIONS :


Latest river height observations for MONDAY 24/08/2009 :

Onkaparinga R at Charleston 1.50 m steady at 5:13 pm Mon
Inverbrackie - Woodside 0.87 m steady at 5:17 pm Mon
Onkaparinga R at Woodside 1.21 m rising at 5:21 pm Mon
Western Branch at Tiers Road 1.45 m rising at 5:20 pm Mon
Lenswood Ck at Lenswood 0.77 m rising at 4:11 pm Mon
Onkaparinga R at Oakbank 0.55 m rising at 5:20 pm Mon
Aldgate Ck at Aldgate 0.37 m steady at 5:00 pm Mon
Onkaparinga R at SE F'way 0.63 m rising at 5:20 pm Mon
Cox Creek at Uraidla 0.30 m steady at 5:17 pm Mon
Houlgraves ALERT 3.44 m steady at 5:12 pm Mon
Clarendon ALERT 9.27 m steady at 5:09 pm Mon
Onkaparinga R - Clarendon 9.16 m steady at 5:20 pm Mon”

Same Place as Peak Flow, Pre-Winter 2010

The distance from where the photos are taken to the river bed is about 5-7 metres vertically.
Posted by: Seina

Re: Streamflow Observations - 11/05/2010 16:05

This is probably a better view.

Peak Flow 2, Winter 2009
Posted by: bigwilly

Re: Streamflow Observations - 11/05/2010 16:06

Interesting stuff Naz! I enjoyed reading that and hope there's more to come.
Posted by: Seina

Re: Streamflow Observations - 11/05/2010 16:10

Lol, I just noticed:

"People are advised to keep away from floodwaters." laugh eek

Originally Posted By: bigwilly
Interesting stuff Naz! I enjoyed reading that and hope there's more to come.

Do you know where I can find daily evaporation observations for the Onkaparinga River?
Posted by: bigwilly

Re: Streamflow Observations - 12/05/2010 07:54

Hi Naz,

The BOM's climate section would be the place to go. You can search by location (Woodside - I don't know the region at all so wouldn't know which adjoining stations would suit) for monthly statistics, which should include pan evaporation.

You might have to do a bit of research to determine the relationship between pan evap. and creek/water body/soil evap.
Posted by: Seina

Re: Streamflow Observations - 18/05/2010 12:48

A much clearer day-time view from 2005:

Peak Flow 3, 3rd September 2005
Posted by: Seina

Re: Streamflow Observations - 29/05/2010 22:10

“There is a non-linear relationship between rainfall and streamflow. That means any single unit reduction in rainfall in the Ranges is likely to lead to a 2–3 unit reduction in streamflow. Future projections are suggesting that there will be reductions in average rainfall from May to October, the most important period to generate runoff in the Mount Lofty Ranges. Modelling from Gillooly and Hutson (2005) of the Cox Creek catchment in the upper Onkaparinga catchment suggest that a 10% reduction in rainfall, the upper limit for projection by 2030, would cause a 24% reduction in stream flow. Such reduced average run-off rates could lead to a greater probability of the phenomenon of green droughts, where there is sufficient rainfall for crop and pasture growth but insufficient for run-off to fill dams and reservoirs. The quality of water could decline with reduced average flows, increasing evaporation, but with extreme erosive events increasing the sediment loads in streams. Such changes will have significant impacts on freshwater ecology (see page 26).

Work by SA Water has suggested that if a mid-point of the CSIRO projections is the eventual outcome, there will be on average a 10% reduction in in-flows, or approximately 20 GL less water, compared with current intake into Adelaide's reservoirs by 2025 (South Australian Government 2004). The 10–15% reduction in average annual rainfall in south-west Western Australia (WA) has led to an approximate halving of the amount of water flowing into Perth’s reservoirs since the 1970s (Pearcey and Terry 2005). Evaporation losses from reservoirs are also likely to increase in association with rises in temperature.

Urban and industrial water supplies in the AMLR region are partly provided from local resources and partly from Murray River water. During dry years, over 80% of Adelaide’s water can be supplied via pipelines from the Murray River. Projected climate change in the Murray Darling Basin is likely to result in reduced flows, and hence a reduced capacity to dilute saline groundwater accessions to the River. Climate change may also increase irrigated crop water demand in response to higher temperatures. Murray Darling Basin Commission (MDBC) has used CSIRO projections to produce indicative estimates of the impact of climate change over the Basin. This modelling suggests an 11% or 2550 GL reduction in flows and an average increase in salinity of 26 EC units at Morgan by 2023 (Andy Close, Water Resources Group MDBC). These levels of change in river condition could enhance conflicts of interest in the distribution of water resources and will continue to require careful anticipatory responses.”

Reference: Bardsley, D., June 2006, p. 18.
Posted by: ROM

Re: Streamflow Observations - 30/05/2010 10:53

As I have posted elsewhere previously, agricultural researchers, acquaintances and friends of mine, at our large ag research institute, the Grains Innovation Park here in Horsham have been doing quite a lot of agricultural crop modelling using the CSIRO's climate models as base for their field crop forecasting research.
However very slight changes in the various versions of the CSIRO's climate models are throwing up large discrepancies in the forecasts and outputs of these CSIRO models.
The CSIRO was contacted by the researchers involved in the modelling as to why these large variations were occurring between versions of the same model.
No reply was forthcoming from the CSIRO.
So the same identical version of a CSIRO climate model was down loaded via the web and this "identical" climate model gave very different output to the supposedly same identical version that the researchers had.
Again no answer at all from the CSIRO as to why.

The CSIRO models are failing completely at the regional level with the various versions of these models often giving directly contrary climate forecasting results for the same identical regions.
That is the experience of these Ag researchers who have repeatedly run these models as a part of their infield crop research and who needless to say are now very scathing to say the least, about the claimed and purported accuracy of the CSIRO's climate models.

And that is exactly the type of modeled regional climate forecasting outlook that is needed by hydrologists to model and predict the flows from the various regions in the Murray / Darling basin.

After listening to these Ag research guys and their experiences with the CSIRO climate models, one of which is used in the 23 climate model suite used by the IPCC for it's climate forecasts, I would not in any way give any credibility to any flow and run off models or forecasts derived from or that used the CSIRO's or any other organisations climate models as a base to provide long term strategies and forecasts for water supplies for any region, particularly if those predictions supposedly extend for more than a half dozen years into the future and cost a huge amount of tax payers hard eared to implement.
Posted by: Seina

Re: Streamflow Observations - 30/05/2010 13:40

Originally Posted By: ROM
As I have posted elsewhere previously, agricultural researchers, acquaintances and friends of mine, at our large ag research institute, the Grains Innovation Park here in Horsham have been doing quite a lot of agricultural crop modelling using the CSIRO's climate models as base for their field crop forecasting research. However very slight changes in the various versions of the CSIRO's climate models are throwing up large discrepancies in the forecasts and outputs of these CSIRO models.

I was actually trying to be informative and present some ideas which may raise some interests and/or questions for those interested in streamflow and surface-water hydrology. I acknowledge that very slight changes in various versions of the CSIRO’s climate models may throw up large discrepancies in forecasts and outputs of these models, however I believe such behaviours fall under scenarios involving sensitive dependence on initial conditions, which are a standard component in computer modelling and experimental analysis. That’s why multiple model scenarios are often considered, with the most likely of those, based on current, scientifically demonstrated knowledge, being the most indicative of what happens in the real world. A balance between being convincing and being sceptical is likely warranted.

Originally Posted By: ROM
The CSIRO was contacted by the researchers involved in the modelling as to why these large variations were occurring between versions of the same model.
No reply was forthcoming from the CSIRO.

Unless there is actual evidence demonstrating impropriety or some degree of angst towards those not involved in the development of CSIRO models, I would say that assuming there is something not right based on a lack of a reply may not carry as much weight as otherwise thought. There may simply be a misinterpretation carried in communication, or something else altogether. I am not making any suggestion about what may or may not being going on, I am simply saying evidence needs to be presented.

Originally Posted By: ROM
The CSIRO models are failing completely at the regional level with the various versions of these models often giving directly contrary climate forecasting results for the same identical regions.

Again, this would fall under sensitive dependence on initial conditions, which may be attributed to programming differences and human error.

Originally Posted By: ROM
After listening to these Ag research guys and their experiences with the CSIRO climate models, one of which is used in the 23 climate model suite used by the IPCC for it's climate forecasts, I would not in any way give any credibility to any flow and run off models or forecasts derived from or that used the CSIRO's or any other organisations climate models as a base to provide long term strategies and forecasts for water supplies for any region, particularly if those predictions supposedly extend for more than a half dozen years into the future and cost a huge amount of tax payers hard eared to implement.

Fair enough, if that’s how you see it smile. I believe that unless one has been in a climate modeller’s shoes and actually understands how the models they have developed work, down to the dotted “I” and crossed “T”, assumptions made about the validity and accuracy or otherwise usefulness of the outputs of climate models should be tempered.

Also this may help:

“There is a non-linear relationship between rainfall and streamflow. That means any single unit reduction in rainfall in the Ranges is likely to lead to a 2–3 unit reduction in streamflow [fact]. Future projections are suggesting that there will be reductions in average rainfall from May to October, the most important period to generate runoff in the Mount Lofty Ranges. Modelling from Gillooly and Hutson (2005) of the Cox Creek catchment in the upper Onkaparinga catchment suggest that a 10% reduction in rainfall, the upper limit for projection by 2030, would cause a 24% reduction in stream flow. Such reduced average run-off rates could lead to a greater probability of the phenomenon of green droughts, where there is sufficient rainfall for crop and pasture growth but insufficient for run-off to fill dams and reservoirs. The quality of water could decline with reduced average flows, increasing evaporation, but with extreme erosive events increasing the sediment loads in streams. Such [suggested] changes will have significant impacts on freshwater ecology (see page 26).

Work by SA Water has suggested that if a mid-point of the CSIRO projections is the eventual outcome, there will be on average a 10% reduction in in-flows, or approximately 20 GL less water, compared with current intake into Adelaide's reservoirs by 2025 (South Australian Government 2004). The 10–15% reduction in average annual rainfall in south-west Western Australia (WA) has led to an approximate halving of the amount of water flowing into Perth’s reservoirs since the 1970s (Pearcey and Terry 2005). Evaporation losses from reservoirs are also likely to increase in association with rises in temperature.

Urban and industrial water supplies in the AMLR region are partly provided from local resources and partly from Murray River water. During dry years, over 80% of Adelaide’s water can be supplied via pipelines from the Murray River [fact]. Projected climate change in the Murray Darling Basin is likely to result in reduced flows, and hence a reduced capacity to dilute saline groundwater accessions to the River. Climate change may also increase irrigated crop water demand in response to higher temperatures. Murray Darling Basin Commission (MDBC) has used CSIRO projections to produce indicative estimates of the impact of climate change over the Basin. This modelling suggests an 11% or 2550 GL reduction in flows and an average increase in salinity of 26 EC units at Morgan by 2023 (Andy Close, Water Resources Group MDBC). These levels of change in river condition could enhance conflicts of interest in the distribution of water resources and will continue to require careful anticipatory responses.”

Bold Added. [] Added.

-------------------------------------------------------------------------------------------------------

Also, I just have a query:

If level of certainty and accuracy about climate modelling by the CSIRO is questionable, how much scientific knowledge is require for us to have any reasonable degree of certainty about what’s going to happen in the future, and the potential impact of what’s happening now on those future outcomes?

Where do we draw the line about facts that are facts without constantly changing our position, and thus our standards of what constitutes enough scientific knowledge?

I invite anyone to put their thoughts forward on this.
Posted by: bd bucketingdown

Re: Streamflow Observations - 30/05/2010 15:13

My models suggest rainfall & stream levels will be back to normal higher levels from now on and is already in that process now from what I can see.
http://www.holtonweather.com/article2.htm
Posted by: Seina

Re: Streamflow Observations - 30/05/2010 17:22

Originally Posted By: Bucketing Down(BD)
My models suggest rainfall & stream levels will be back to normal higher levels from now on and is already in that process now from what I can see. http://www.holtonweather.com/article2.htm

I do not doubt there is some legitimacy and validity to what you have found, however, as I understand it, modelling streamflow, especially on a daily timescale, is a very complex and site-specific endeavour. This can likely be seen in the differences in stream behaviour evident across the Mount Lofty Ranges, where close-proximity streams within the same catchment can exhibit both perennial and ephemeral behaviours, meaning while one stream flows all year round without ever being dry (within its recorded history), another streams flow intermittently depending in several factors, including vegetation cover and osmotic processes, inflexion points of flow behaviour due to the nature of underground flow dynamics, and detention rates (which are likely dependent on the passage or atmospheric high- and low-pressure systems).

I do not question so much that water could become more available (and evidenced by the potential for an intensification in the water cycle due not only to natural variations in climate, but also anthropogenic, including modifications of the landscape for agricultural and horticultural practices), it is more in what form it is available and where this is sourced from.

Weather systems do not necessarily have to become more or less frequent for impacts on streamflow to be witnessed on the ground. If, by land-use changes alone, the characteristic contributing behaviours of intermediary processes between weather systems and streamflow responses are modified or changed in such way that is not fully understood or appreciated in streamflow observations, the implications alone are that the intensity of weather events (as suggested by modelling of the relationship between saturation vapour pressure and temperature) has the capacity to alter streamflow behaviour.

If observations of the Onkaparinga River in the Central Adelaide Hills earlier this year, before significant rains, are anything to go by, the translation of rainfall into soil moisture over the last 20 years, and possibly longer, has not been going so well, the major floods of 1992, 1994 and 1996 not withstanding. The river is not even flowing yet (today), and we’ve had over 65 mm in the last week, some of which is still visible on the surface and hasn’t even soaked in. So the question is what kind of rainfall over what period, short of flooding the local neighbourhoods, will lead to streamflow? My current estimate is around 15 mm/hr over several hours, but that’s probably just a guess given how little we understand about underground systems compared to surface-water systems.

This from the same page as the previous quote:

Groundwater resource responses to climate change are less clear, partly because the hydrology of groundwater is not fully understood. While some groundwater resources are highly sensitive to rainfall changes, others are insensitive in the short-term. Reduced rainfall could lead to reduced rates of groundwater recharge and subsequent reductions in problems associated with waterlogging and secondary dryland salinity. On the other hand, reduced water-use efficiency may result from more unreliable and variable rainfall, and occasional extreme rainfall events could lead to large slugs of water penetrating through to replenish perched aquifers (Table 6).”

There is one thing in particular that seems to be apparent from rainfall events over the last few years: they have become much more concentrated in clusters of days, rather than spread out over days and weeks in a continuous fashion, .i.e. their reliability appears to have reduced, their variability increased. The passage of high- and low-pressure systems has also become somewhat more meridional (north-to-south oriented) and less zonal (less continuous passage of frontal systems within a given latitudinal range). I am by no means an expert on these things, however as rainfall represents the most significant and direct contribution to streamflow, it seems reasonable that an understanding of trends in weather patterns (and whether they are stationary or non-stationary trends, sinusoidal, have inflexion points, etc.) is critical to getting a better idea of how much quality water is really available in quantifiable terms, within the region.
Posted by: ROM

Re: Streamflow Observations - 30/05/2010 17:29

No reflection on you in any way was mean't Nazdeck and you are way out in front of any knowledge base that I have when it comes to a lot of the info you post here.
But that does not mean we should just sit here and swallow what the expert's deliver as some of the experts are coming spectacularly undone quite frequently these days by ordinary people asking quite relevant questions or pointing out some salient and unacknowledged or deliberately avoided facts and data.
The web has seen to that!

Unfortunately so much of what we are now told must be correct because it is based on "models" and as you have posted, models are very, very subject to initial inputs and conditions.
And as is being commented on more and more by modelers themselves from professions other than climate modelling and something that is now acknowledged as being rife in climate modeling is that a modelers frequently select some input criteria that at best is fuzzy in it's accuracy and credibility and often they just select data inputs that are no more than guess work or because the data input "feels" right.
And there are cases where they are quoted as actually saying this.

You might question the skills of the local Ag modelers that I have referred to but unlike the climate modelers these guys and a lot of gals nowadays, live and die professionally by their in field results that are a direct outcome of their modeling and then putting the output of that modeling into actual field conditions to verify those models and the predictions arising from that modeling.
No different to the way in which modeling is used in countless other professions from engineering to medicine to modeling the atomic structure of elements and the bosons, protons, quarks and etc and then verifying those predictions in the big nuclear particle colliders.
In the cases above, unlike climate modeling, the outcomes of that modeling can usually be verified within a short time frame and if the modeled outcome is different to reality then the necessary changes in the actual model and data inputs can be made before any serious damage is done to the subject that is being modeled.

And those Ag modelers use the CSIRO's models as supplied direct from the CSIRO as the basic climate forecasting tool on which to base a lot of their crop models and those CSIRO models are simply not consistent in their climate predictions particularly when it gets down to regional climate predictions and effects.
And that regional climate forecast part is critical for everybody as not many people will give a damn if the model says Australia will warm by x number of thousands'th of a degree in 20 years time.
Rather they will say, yeh! now how will it affect me in this patch?
And the CSIRO climate models simply can't do that forecast and if they try then they often give different and sometimes quite contrary results.

By it's very nature climate models can't be verified so it is pretty bloody stupid to bet the house on the predictions of usually years ahead climate and runoff flow based entirely on these climate models output.
Even less smart, in view of the experiences of our local modelers re the CSIRO's regional model predictions is to bet the farm on model predicted outcomes in the smaller scale regions, outcomes which may not be known for many years ahead.

A hell of a lot of damage and unnecessary angst can be caused by taking precipitous action based on these output of these climate models .
Stream flow predictions that are grossly wrong can lead to the wrong direction being taken by entire industries, housing and urban buildings and entire business precincts being placed in the wrong location, [ something that based on historical events well within my memory may have been done locally. will be interesting when we get the next really big a couple times a century floods. ] industries being set up on the basis of the models and enormous amounts of taxpayers money being frittered away on still born projects.

In the case of runoff and stream flows, better to just go back in history, written, oral and archeological and see what has happened in the past and build on that as the base for the decision making that is required for the future as nature has a habit of repeating herself regardless of puny mankind's intentions.

Modeling should be a case of "Trust but verify!" and if you can't verify then you do not trust in any way and that applies particularly to climate modeling and any other modeling that relies totally on the veracity of the climate models for their base data no matter what the climate models origin is.
Posted by: bd bucketingdown

Re: Streamflow Observations - 30/05/2010 19:14

"There is one thing in particular that seems to be apparent from rainfall events over the last few years: they have become much more concentrated in clusters of days, rather than spread out over days and weeks in a continuous fashion, .i.e. their reliability appears to have reduced, their variability increased. The passage of high- and low-pressure systems has also become somewhat more meridional (north-to-south oriented) and less zonal (less continuous passage of frontal systems within a given latitudinal range). I am by no means an expert on these things, however as rainfall represents the most significant and direct contribution to streamflow, it seems reasonable that an understanding of trends in weather patterns (and whether they are stationary or non-stationary trends, sinusoidal, have inflexion points, etc.) is critical to getting a better idea of how much quality water is really available in quantifiable terms, within the region."(Quote Naz)

Naz, the only part I was commenting on was like is in this paragraph(I am not into the rest of the post enough to comment, as my dealings are only with the more major Murray system forecasting wise)...But that is exactyly my point, past weather or persistence is a very poor forecasting tool. The weather and rainfall run in cycles & some are sinusoidal, yes, and all the past and currentccycles imo suggest that we will return to a more "normal" whatever that is, rainfall pattern. Systems of pressure and weather again imo will return to more what we have been used to before the last 10 years of dryness. It is all cyclic, and nothing to do with global warming, it is mainly caused by solar effects which rule the long term weather and rainfall trends, again imo from years and years of research. And 2010 is startying to well bear out what I am saying...even the past week
eg
Weather News & Web Pages of Interest:
^^^ Lots of Australian wild, stormy, floody, heavy & record breaking rains in the past week!
http://www.weatherzone.com.au/news/biggest-downpour-in-years-soaks-was-southwest/14430
http://www.weatherzone.com.au/news/destructive-winds-smash-into-nsw/14452
http://www.weatherzone.com.au/news/flooding-isolates-tasmanian-residents/14437
http://www.weatherzone.com.au/news/gippsland-watches-rising-rivers/14454
http://www.weatherzone.com.au/news/storms-dump-rain-across-sa/14416
http://www.weatherzone.com.au/news/storms-rip-into-the-nt/14445
http://www.weatherzone.com.au/news/tasmania-awash/14444
http://www.weatherzone.com.au/news/wettest-day-in-weeks-for-south-australia/14419
http://www.weatherzone.com.au/news/wettest-may-day-on-record-for-moomba/14412
http://www.abc.net.au/rural/content/2010/s2912346.htm?site=southeastnsw

Cheers Ian PS Nice rains we are having here at Nairne and you as well I guess Naz at Woodside...We have had 40mm so far and its still thickly raining here, almost all day long!
Posted by: Seina

Re: Streamflow Observations - 30/05/2010 21:38

Originally Posted By: ROM
But that does not mean we should just sit here and swallow what the expert's deliver as some of the experts are coming spectacularly undone quite frequently these days by ordinary people asking quite relevant questions or pointing out some salient and unacknowledged or deliberately avoided facts and data.
The web has seen to that!

In many respect I agree with you one those points :), particularly in relation to the use and abuse of internet resources. I agree that more transparency in scientific practices is mostly probably warranted, and that the knowledge and experience base of those who see things happening first-hand in the field should not be considered merely as a supplementary source of information in mathematically-dominated modelling practices. Given that without that knowledge and experience, input into mathematical models would be on rather poor foundations, I think it is very important. I also think there should be more stringent criteria against which hypothetical and theoretical ideas must be tested before they can pass as valid.

Originally Posted By: ROM
Unfortunately so much of what we are now told must be correct because it is based on "models" and as you have posted, models are very, very subject to initial inputs and conditions.

I would say initial model input data and boundary conditions need to be rather stringent, given the output of models is only representational.

Originally Posted By: ROM
And as is being commented on more and more by modelers themselves from professions other than climate modelling and something that is now acknowledged as being rife in climate modeling is that a modelers frequently select some input criteria that at best is fuzzy in it's accuracy and credibility and often they just select data inputs that are no more than guess work or because the data input "feels" right. And there are cases where they are quoted as actually saying this.

Lol re: "feels" right, couldn’t agree more :), hence the term “representational” above.

Originally Posted By: ROM
You might question the skills of the local Ag modelers that I have referred to but unlike the climate modelers these guys and a lot of gals nowadays, live and die professionally by their in field results that are a direct outcome of their modeling and then putting the output of that modeling into actual field conditions to verify those models and the predictions arising from that modeling.

Your point (concerning bias data input) above cleared that up a bit for me, thanks smile. Additionally, to clarify, I was not actually questioning the skills of modellers, more the interpretation of information in communication between the group you identified as “feels” right, and the local agricultural modellers, as you pointed out.

Originally Posted By: ROM
In the cases above, unlike climate modeling, the outcomes of that modeling can usually be verified within a short time frame and if the modeled outcome is different to reality then the necessary changes in the actual model and data inputs can be made before any serious damage is done to the subject that is being modeled.

And those Ag modelers use the CSIRO's models as supplied direct from the CSIRO as the basic climate forecasting tool on which to base a lot of their crop models and those CSIRO models are simply not consistent in their climate predictions particularly when it gets down to regional climate predictions and effects.

Ok, I see your point – I was probably thinking more case- and site-specific. I am mostly sceptical of the inputs and outputs to and from any computer model that has not been scientifically validated within a given range of uncertainty, and which does not have specific boundary conditions.

Originally Posted By: ROM
A hell of a lot of damage and unnecessary angst can be caused by taking precipitous action based on these output of these climate models.

Agreed.

Originally Posted By: ROM
In the case of runoff and stream flows, better to just go back in history, written, oral and archeological and see what has happened in the past and build on that as the base for the decision making that is required for the future as nature has a habit of repeating herself regardless of puny mankind's intentions.

Practically, I would say a potential first step would be to construct comprehensive streamflow records from that we already have and know.

Originally Posted By: Bucketing Down(BD)
Naz, the only part I was commenting on was like is in this paragraph(I am not into the rest of the post enough to comment, as my dealings are only with the more major Murray system forecasting wise)...

Thanks for clarifying smile.

PS, I was actually competing (sport) out in this stuff today lol. Will endeavour to post rainfall totals soon in other thread.
Posted by: Seina

Re: Streamflow Observations - 06/06/2010 12:55

To be honest, I'm not sure about the impact of AGW on streamflow, because there doesn't seem to be a clear trend (other than stationary) that reflects AGW in Adelaide Mount Lofty Ranges rainfall records.
Posted by: Seina

Re: Streamflow Observations - 13/06/2010 12:20

I have done a bit of a statistical analysis for several areas in the Mount Lofty Ranges using data made available to the public by the DWLBC. The results for the rainfall and streamflow look fairly interesting and there are two things I have noted in particular:
  • The closer the rainfall site, the higher the correlation – this is not necessarily true, and
  • The higher the correlation between rainfall and streamflow, the more predictable streamflow is – this is not necessarily true.
Posted by: Seina

Re: Streamflow Observations - 15/06/2010 12:18

Originally Posted By: Bucketing Down(BD)
The weather and rainfall run in cycles & some are sinusoidal, yes, and all the past and currentccycles imo suggest that we will return to a more "normal" whatever that is, rainfall pattern. Systems of pressure and weather again imo will return to more what we have been used to before the last 10 years of dryness. It is all cyclic, and nothing to do with global warming, it is mainly caused by solar effects which rule the long term weather and rainfall trends, again imo from years and years of research.

I’m a little sceptical about the weather and climate patterns in the southern hemisphere “returning to normal,” just as I’m sceptical of exaggerated claims of AGW. There are two apparent trends which are pretty clear to me after reading a report from the BoM, for Adelaide. Credit: R. J. Szkup and B. H. Brooks.

The first is that there were a greater number of heatwave events in the earlier part of last century from roughly 1890 to 1940 in Adelaide, which was consistent stationary or near-stationary high-pressure systems in the Indian Ocean, which likely blocked the passage of numerous frontal systems during that period. After 1940, these synoptic situations seemed to have become less frequent or dominant, up until about the years 1990, before beginning to rise again by the year 2000. Indeed this may be evidence of cyclic climate behaviour, over periods of several decades. However, given the recent slight increases in heatwave conditions since 2000 the question is, even if this is a natural cyclic or sinusoidal trend, when does the dominance of the high-pressure synoptic systems in the Indian Ocean return, or is it beginning to already?

The second apparent trend, or rather lack of trend, has to do with ENSO events (El Niños and La Ninas). The above mentioned heatwave events, judging from the BoM report, do not align strongly with the onset of ENSO event (out of all significant events 1890 to 2000, 3 of 12 Heatwaves aligned with El Niños, and 4 of 12 aligned with La Ninas).
Posted by: Seina

Re: Streamflow Observations - 15/06/2010 12:36

Sorry, 3 of 12 La Nina, 4 of 12 El Nino, my blue.
Posted by: Seina

Re: Streamflow Observations - 27/06/2010 12:38

Pools in the local river are filling up. I think as each pool fills up, this flow goes into the next pool downstream. So flows further upstream seem to have started, but pools further downstream are still filling up. I think this might be the base flow part of streamflow (to do with the soil) until we get more rain.
Posted by: Seina

Re: Streamflow Observations - 28/06/2010 21:52

The rainfall for this area of the hills continues to be below average. All months this year show totals below the long-term average for those months. The last period when we received enough rain to lead to the local river reaching near the river bank was back during 2004 and 2005. For this period I have rainfall temperature and some climate records. I will wait and see how these records factor into the equation of changing climate. Something will change and most probably has the capacity to change in the southern ocean, and this will probably be particularly important for South Australia smile.
Posted by: Seina

Re: Streamflow Observations - 28/06/2010 22:19

Originally Posted By: -Cosmic-
Something will change...

I'm sceptical enough of AGW to consider it anyway smile. Streams seem to have fairly long memories lol.
Posted by: Seina

Re: Streamflow Observations - 30/06/2010 12:41

Onkaparinga River 27th June 2010

In the last 2 days we’ve had 6.3 mm.

Onkaparinga River 30th June 2010

With 20.2 mm in the last 3 days, the height of water in the local river has risen dramatically. Where there are obstacles to natural flow, the water level at a glance is half to 1 metre below the river bank in parts. There is now definitely streamflow, even though it's still base flow, and a trickle. About 100 metres upstream from the 1st observation point, the river is flowing more strongly with natural flows clearly visible.

Since the start of 2010, we've had roughly 190.2 mm (we don't have an AWS). The long-term mean to date is 346.3. The previous large rain total we've had was 49 mm to the 29th of November last year.
Posted by: Seina

Re: Streamflow Observations - 30/06/2010 12:58

Monthly/Annual Rainfall Totals 2004, 2005

Year/Month 2004 2005 Long-term
Jan 14.6 32.6 25.5
Feb 8.4 31.3 27.3
Mar 34.9 8.7 29.9
Apr 25.6 10.5 59.7
May 54.6 6.9 93
Jun 199.7 212.2 110.9
Jul 115.2 67 117.2
Aug 158.8 122.3 112.2
Sep 57.4 93.4 91.6
Oct 12.9 128.2 69
Nov 58.8 87.3 40.8
Dec 63 44 32.2
Total 803.9 844.4 809.3
Posted by: Seina

Re: Streamflow Observations - 06/07/2010 10:55

Onkaparinga River 6th July 2010

Yet another night with sub zero temps. These have been very common in the last few weeks, including a rather big frost only a couple of days ago (very clear in the paddocks). Little or no rain since the last major rainfall event (maybe 0.1 mm). I am thinking that the low temperatures are in someway contributing to reduced river flows. The height of water in the river has not changed much since the 30th, maybe .25 to .3 metres. The flow is still a trickle, although the water in more stagnant than it was a week ago. This seems to mean it takes longer for base flow to be affected by a lack of rain than quick flow (runoff). I would guess that when rains are enough to get above the main base flow water height, that the changes in flow will be more noticeable. I am beginning to get somewhat concerned by the lack from at this point for July, and am getting increasingly suspicious that the effects of pressure, temperature and lack of rain in the region and on larger scales is contributing rather a lot to these seemingly record low flows (in at least 20 years). We should be getting consecutive strong cold front crossing the Bight, and this is just not happening. I am getting a stronger and stronger sense this year will be below average rainfall (we're already way behind).
Posted by: Seina

Re: Streamflow Observations - 06/07/2010 13:37

If this year is anything like 2009, we might not see peaks in winter flow until August.
Posted by: Seina

Re: Streamflow Observations - 06/07/2010 14:20

Photographic evidence from August and December 1992 shows that when the Onkaparinga River bursts its banks, the area covered by water increases from 5-10 metres (river width) to a massive 50-100 metres. In terms of floods, it looks like there was torrential rain in 1992.

Edit: Unfortunately, rainfall records were not kept during this period in the area, so recontructions would probably be needed to estimate flows.
Posted by: Seina

Re: Streamflow Observations - 10/07/2010 12:27

Reconstructed records indicate that during August 1992, over 70 mm fell in a single day, and that over a 5 day period in December, over 110 mm fell.

Streamflow Observations 6th July 2010
Posted by: Seina

Re: Streamflow Observations - 10/07/2010 12:46

Streamflow records from the lower Onkaparinga River (see http://e-nrims.dwlbc.sa.gov.au/swa/) appear to indicate 1992 was the wettest year in the period June 1977 to November 2006.
Posted by: Seina

Re: Streamflow Observations - 12/07/2010 14:02

Some experimental streamflow modelling I have done for catchments in the Adelaide Hills seems to show that, on a daily scale, while streamflow magnitude is not well captured over many years, the response of streamflow to rainfall does seem to be consistent. While I do not fully understand the physics of the modelling, the relationship between rainfall and streamflow on daily and monthly time scales seems to be very similar. I am highly suspicious that rainfall this year will not be sufficient to generate reasonable flows, and more so because the strength of rain events to date since January 1st is reflected in the monthly rainfall totals, which are well below the long-term average. Given catchments tend to have a fairly long memory for rainfall events, this only serves to highlight the importance of significant and sustained rainfall throughout the winter months.
Posted by: Seina

Re: Streamflow Observations - 12/07/2010 14:21

My prediction for streamflow response over the next 6 months:

N.B.: This is a guide only.

July 2010: Below Average Streamflow Response.
August 2010: Above Average Streamflow Response (Streamflow Will Peak).
September 2010: Above Average Streamflow Response.
October 2010: Below Average Streamflow Response.
November 2010: Average Streamflow Response.
December 2010: Below Average Streamflow Response.
Posted by: Seina

Re: Streamflow Observations - 14/07/2010 14:42

Onkaparinga River 14th July 2010

22 mm between 12 pm on the 8th and 9:55 pm last night, plus 19 mm to 9 am this morning, plus another 5 mm to 10:20 am has lead to the level of water in the local river rising to about 0.5 m from the riverbank. The river (at 10:20 am) was flowing strongly, yet steadily, without signs of flooding yet apart from water in paddocks which is yet to soak into the soil (up to an inch deep in places). Of the 46 mm we have received over the last week, the 19 mm to 9 am has been the most significant and sustained rainfall event for the year. After 9 am, at least 2-3 thunderstorms moved through the area with sharp downpours and frequent thunder. Small hail has been intermittent. The rain which has already fallen has probably increased the streamflow response from slight to mild-to-moderate, so there are strong signs the winter pattern has set in. I would say the water is about 1.5-2 m deep in sections of the river where there are no visible rapids. At this stage I would not say streamflow has reached its peak given we’re still in the middle of winter, which would seem somewhat obvious. Indications are that we are approaching peak flow, which seems likely to occur sometime in late July/early August (given what’s happened to date this year) *. (* See Bottom of Post).

As a side note on a previous post about floods in August and December 1992, the vegetation (trees and shrubs) covering the riverbanks and surrounds at the time was very young and not very tall or dense, indicating there could have been a greater potential flooding than the is now because of the difference in surface vegetation cover and its density (including the tree canopy). I have a feeling that the local river environment actually increases rainfall somewhat or supports itself through generating an environment which contributes to increased humidity and in someway changes local dynamics in the atmosphere. Most unwanted species of plants have been removed from the area closest, leaving the native species to thrive. Judging from photographs 18 years ago, this landscape was very bare (only grass) back then which may mean its capacity to absorb large quantities of water has increased significantly since then.

* [One thing that is somewhat unusual for this time of year is that some flowering plants have begun to bloom – this leaves me wondering whether an August forecast for peak flow truly reflects these observations, and whether July will be the wettest month…something to keep in mind (local knowledge suggests the seasons may have shifted forward 2-3 months of the standard 3 month definitions).]
Posted by: Seina

Re: Streamflow Observations - 14/07/2010 15:00

The difference in the water level between photos taken of the river at 9 am and at 10:20 am was not really noticeable after a strong downpour. I may have the photos from 10:20 up soon after I upload them smile.
Posted by: Seina

Re: Streamflow Observations - 14/07/2010 19:27

Onkaparinga Streamflow Downstream 10.20 am CST 14th July 2010

Onkaparinga Streamflow Upstream 10.20 am CST 14th July 2010
Posted by: Seina

Re: Streamflow Observations - 14/07/2010 19:38

This is the riverbed for comparison in a deep section with what looks like bedrock

Riverbed Pre-Winter 2010, 11th May 2010, 11.04 am

I'm thinking about getting the old flood photos digitised to give an idea of just how wet it can get smile (in the absence of dense tree cover).
Posted by: Seina

Re: Streamflow Observations - 14/07/2010 19:56

It interesting to note that, in the above photo, there is boundary line through the riverbank. I believe this could be the minimum flow level, or what is supposed to be minimum flow level. I have another photo of the same boundary line further upstream at right angles to the river bank and the it looks very similar. It's about half a metre above the water level (where there is water), taken on the same day.
Posted by: Thunderstruck

Re: Streamflow Observations - 15/07/2010 07:55

Good stuff mate smile enjoy these obs, all very interesting. Keep the pics coming!

TS cool
Posted by: _Johnno_

Re: Streamflow Observations - 15/07/2010 12:10

Interesting to see 5 river systems having minor flood warnings for North East Victoria haven't seen that for a while, hope it continues rest of Winter & into Spring
Posted by: Seina

Re: Streamflow Observations - 15/07/2010 12:13

If you have any obs for rivers anywhere else you would like to post in here, you're more than welcome smile.
Posted by: Thunderstruck

Re: Streamflow Observations - 15/07/2010 12:49

Originally Posted By: _Johnno_
Interesting to see 5 river systems having minor flood warnings for North East Victoria haven't seen that for a while, hope it continues rest of Winter & into Spring


Yer noticed that, I honestly cannot recall seeing that on my entire time in these forums, well more-so the Murray Catchment. Great to see indeed and hopefully the strengthening La Nina does more good.

TS cool
Posted by: Seina

Re: Streamflow Observations - 18/07/2010 17:35

Winter 2010, Upstream Onkaparinga 18th July 2010, 1.27 pm

Winter 2010, Downstream Onkaparinga 18th July 2010, 1.27 pm

…1.7 mm in the 24 hours to 4:55 pm.
Posted by: Seina

Re: Streamflow Observations - 20/07/2010 13:40

Another 4.4 mm over 2 days, and it is more apparent that the water level is receding at locations down stream. It was raining at about 12:30 this afternoon, but I managed to get what might be the best photo of the local river to date, looking downstream 150-200 metres upstream from the previous two photos.

Streamflow Onkaparinga River, Winter 2010, 20th July, approx. 12.40 pm

Also, further upstream from the above location, the water appears to be at about the level of the minimum water level (see photo below), or even a bit higher, as no dark soil is visible along the edges of the riverbed. That’s probably a half metre rise in the water level, mostly resulting from the 19 mm we received to 9 am on the 14th, but with some coming after (about 55.7 mm in 9 days to 11 am on the 17th of July).

Streamflow Onkaparinga River Further Upstream, Winter 2010, 20th July, approx. 12.35 pm
Posted by: Seina

Re: Streamflow Observations - 20/07/2010 14:01

I said minimum water level above because the photo below gives an idea of what streamflow for the Onkaparinga can be like.

Streamflow September 2005

...and that's not even close to magnitude of flow in 1992.
Posted by: Seina

Re: Streamflow Observations - 29/07/2010 22:47

------------------------------------------------------
Update:

Onkaparinga River 24th July 2010

Temperature is currently 12 C in the early afternoon (around 2 pm).

Nothing much to report in recent times. Here are a couple of photos further downstream (probably over half a kilometre from the last photos).

Upstream Onkaparinga River 20th July 2010, 2.40 pm

Downstream Onkaparinga River 20th July 2010, 2.40 pm

Also of interest earlier in July was the passing of what looked like severe mammatus clouds stretching from horizon to horizon, northeast to south west. This was followed by a system of severe winds (I don’t have footage of these as it was very early morning, but it’s enough to say they were strong enough that some very large trees were swaying in them, gusts I would guess up to 100 km/h). We received about 11 mm overnight from that system, but it didn’t really contribute much at all (to streamflow).

Mammatus Approaching 9th July 2010, approx. 6 pm

Mammatus Leaving 9th July 2010, approx. 6 pm

The quality of the last two images was not great because of the time of day, and I’m not exactly an expert in photography.

------------------------------------------------------
Update:

Onkaparinga River 28th July 2010

Taken a little over 5 hours before it started raining:

Downstream Onkaparinga River, 28th July, 5.42 pm

The water level has not fallen much since the 24th (less than 0.5 m). Seems to mean water retention is good for what we have received so far this winter (124 mm). I also noticed an ant nest had been built 2-3 m above the main area of water flow. Might point to the height of peak flow in coming weeks (in other words, possibly no major flooding this year). Can’t be more certain about the timing of peak flow yet, however indications suggest the date may be in mid-to-late August.

------------------------------------------------------
Update:

Onkaparinga River 29th July 2010

10.7 mm to 8:55 am since 11 pm last night, and drizzle with the occasional light-to-moderate shower – 1.8 mm to 2:30 pm. It’s been a very murky sky for most of the day with overcast conditions. The drizzle has often been so fine it’s just drifted to the ground. Temperature was 10 C at 11:26 am.

I would be guessing, but I think unless we get falls in excess of 10-15 mm in the next 24 hours, we’re not going to see significant changes in streamflow (will probably wait until then next strong system before taking more observations). The current rate of rainfall (which is near constant drizzle) is probably not enough to have any noticeable impact.

------------------------------------------------------
Update:

When comparing this:

Onkaparinga River Downstream 28th July 2010, 5.39 pm

With this:

Onkaparinga River Downstream 29th July 2010, 3.16 pm

There is a noticeable change in the level of water, and the streamflow response after firstly the 10.7 mm to 8:55 am and then around 2 mm or more in the afternoon. This seems to indicate the retention of water in the system is sufficient to increase flows by 5-10 cm – 12.5 mm rain gives 5-10 cm change.
Posted by: bd bucketingdown

Re: Streamflow Observations - 01/08/2010 11:37

Directly related to streamflow observations, but on the most major river system in Australia:
I have an official historical table and graphs of Monthly Murray Darling Dam Inflows for Hume & Dartmouth Dams from 1892 to current 2010(Courtesy MBD Commission), on my new upgraded, updated, modernised web site under articles section for anyone who may be interested at
http://www.holtonweather.com
Posted by: Seina

Re: Streamflow Observations - 01/08/2010 15:53

Onkaparinga River 30th July 2010

Further upstream towards Charleston and Springhead (where the source of the Onkaparinga is) there is likely to have been more rainfall in the past 2 days than there has been at Woodside – the water level was even higher at 12:30 pm than it was a 3:16 pm yesterday (29th), and the change in the streamflow response is noticeable. I do not think the 2.8 mm yesterday is what caused the water level to rise – it seems far more likely this occurred because flow increased many kilometres upstream.

The water content of the soil is pretty clear given that after a little over half an inch up to yesterday, water was still soaking into the paddocks. The forecast for showers over the coming days seems to be promising; we’ve already had a few light, sharp showers today, though they haven’t been sustained yet. The streamflow response is unlikely to change much until they do become sustained.

Onkaparinga River 1st August 2010

First, a correction: 81.4 mm for June, 95.7 mm for July, and about 14.3 to start August. We have just had a moderate shower pass through the area (12 pm). It is now sunny. At around 12:10 am last night, a severe thunderstorm on a squall line (the second of 2) passed through the region. This brought with it very heavy rain/hail for a few minutes, and heavy rainfall over a period of 5-10 minutes. There was small hail, close and frequent thunder and lightning, and I suspect we got caught in a microburst. Taking photos of the river this morning, after a further 13 mm overnight, most probably coming from the thunderstorm, it was clear the peak flow had passed. The river was swollen at 9 am (and could not be crossed), and the peak water mark was visible a further half to one metre up the riverbank. It is very wet underfoot and some rain has not soaked into the soil.

Streamflow Onkaparinga River, 9.01 am 1st August 2010
Streamflow Onkaparinga River, 9.02 am 1st August 2010
Streamflow Onkaparinga River, 9.03 am 1st August 2010 – High Water Mark

In the 24 hours to 9 am we’ve had about 27 mm, with another 3.1 to midday.

Hi BD,

Just at a glance it looks very interesting with the historical inflow records smile. I would assume that to reconstruct these kinds of records you would need some sort of precipitation and evapotranspiration input data from further upstream from where the inflow records were taken!?
Posted by: bd bucketingdown

Re: Streamflow Observations - 01/08/2010 21:01

Hi Cosmic

These are simply the natural inflow data to the Hume and Dartmouth Dams(by deleting any unnatural sources ie piping from Snowy, etc).
They were compliled by MBD commission for me at my request. I asked for the monthly natural inflow data to the hume and dartmouth dams, and that is what they supplied me months later(So I am not fully certain what they delete out of the original inflows).
I use the data to formulate my dam inflow forecasting models for a certain large irrigation authority, but thought that others might like the raw data for studies, so I asked them if I could put the data on my website, to which they agreed, as long as it was available to all.
Cheers BD

Posted by: Seina

Re: Streamflow Observations - 01/08/2010 22:03

Ok smile.
Posted by: Seina

Re: Streamflow Observations - 04/08/2010 22:53

Onkaparinga River 6 pm 4th August 2010

Roughly 70 mm in less than 7 days has the river resembling a raging torrent, yet still below minor flood level. The photo below is taken rather hastily in an attempt to capture the remaining flow late in the evening (probably well past peak flow for the weather system). The flow level in the photograph is probably at least a metre below the peak flow reached during the day.

Streamflow Onkaparinga River, 4th August 2010, 5.55 pm
Posted by: Seina

Re: Streamflow Observations - 14/08/2010 14:34

Streamflow Onkaparinga River, 14 August 2010, 1.45 pm

Streamflow Onkaparinga River, 14 August 2010, 1.47 pm
Posted by: Seina

Re: Streamflow Observations - 14/08/2010 14:47

...After 22.5 mm in less than 24 hrs smile.
Posted by: Seina

Re: Streamflow Observations - 15/08/2010 20:31

Hopefully this works :):

Video 1 Streamflow Onkaparinga River, 14th August 2010, 1.47 pm – Peak Flow 1

Peak Flow 2 was early in the morning the following day.
Posted by: Seina

Re: Streamflow Observations - 15/08/2010 20:45

This is how wet it was underfoot earlier yesterday:

Rain at 10.45 am, 14th August 2010

N.B.: Peak Flow 2 was higher than Peak Flow 1 smile.
Posted by: Seina

Re: Streamflow Observations - 20/08/2010 23:04

Previously:

Onkaparinga River 4.50 pm 6th August 2010

23.3 mm since 3:20 pm on the 3rd of August plus another 15.5 since the beginning of the month gives 38.8 total for the month. The most significant falls occurred on the 1st and 3rd. Flows are moderate and well above levels on the 30th of July, but not higher than on the morning of the 1st, at 9 am.

Onkaparinga River 4.30 pm 7th August 2010

Streamflow has increased slightly over the last 24 hours; only 0.1 mm in that time.

Onkaparinga River 17th August 2010 – Possibly Peak Winter Flow

Since roughly 4 am on the 15th, flows have steadied and are now falling.
The volume of water measured travelling down the river at A5031001: Onkaparinga R US Dissipater (http://e-nrims.dwlbc.sa.gov.au/swa/) was about 5026 ML/day at 9 am, the peak, while at Woodside Weir (http://www.bom.gov.au/fwo/IDS60247/IDS60247.523714.plt.shtml)the water level peaked at 4:02 am at 1.16 metres. This was still below minor flood level.

We’ve had another 5.7 mm in the last 2 days, bringing the total for the month to 97.6 mm, and the total for June to August to 274.7 mm.

Currently:

Observations and Update 20th of August 2010

Since 12:45 pm on the 14th of August we’ve received 50.8 mm to 5:15 pm today. At 1:23 pm to the 16th, streamflow peaked at Woodside Weir at 0.34 metres, and again at 10:23 pm on the 19th at 0.46 metres. While the river is still running moderately, flows have generally steadied and recent rains suggest flows are simply being maintained and increased slightly. Over the last three days we have averaged 9.2 mm per day.

Total rainfall for August to date is 122.3 mm, with 299.4 mm for winter. This is within 50 mm of the June to August average. Several periods of 24-48 hour falls have exceeded 10 mm. The highest fall of 22 mm was record in the 22 hours to 10 am on the 17th of June.

Edit: I just noticed Woodside Weir flows have hit 1 metre.
Posted by: Seina

Re: Streamflow Observations - 24/08/2010 13:18

The Onkaparinga River at Johnston Rd (Oakbank) on the 20th at 11:09 pm reach minor flood level.
Posted by: Surly Bond

Re: Streamflow Observations - 25/08/2010 17:26

The Namoi River is flowing high enough for me to see the water from my window. It has been doing it for days. I am reflecting on how rare this sight has become.
Keepit Dam is filling up now, despite the determination of the authorities to empty it out. They have had it steady at 26% for years, despite 2007 and 2008 having rainfall well above average. I was beginning to think that demand would permanently exceed supply. Now Keepit Dam is up to 51%. It will take a little while to use that up.
The smaller upper storage, Split Rock Dam, which filled completely in winter 1998, but was rapidly used up, and has been steady at 2.6% for as long as I can remember, has more than doubled in volume to 5.9%. That could be used in the twinkling of an eye.
Posted by: Seina

Re: Streamflow Observations - 25/08/2010 17:52

There should be a warning out. or at least a watch - the river passed minor flood level at 3:48 pm!

It's probably not safe to go down within 5 metres of it atm! There is a huge volume of water flowing downstream at a rapid rate. The river has risen 2-3 metres since last night.
Posted by: teckert

Re: Streamflow Observations - 25/08/2010 18:05

Yer I cant understand why there isnt really.... with 10-20mm+ expected again in next 24 hrs, surely further rises would be expected...
Ch 10 just showed footage of paddocks already under water from the burst Lenswood Creek.
Posted by: Seina

Re: Streamflow Observations - 25/08/2010 20:24

They should issue a flood warning, it's absolutely pi''ing outside!

Streamflow Onkaparinga River, 25th August 2010, 5.32 pm

Streamflow Onkaparinga River, 25th August 2010, 5.33 pm
Posted by: Seina

Re: Streamflow Observations - 26/08/2010 23:11

Video 2, Streamflow Onkaparinga River, 25th August 2010, 5.30 pm, Peak Flow 3
Posted by: Seina

Re: Streamflow Observations - 31/08/2010 21:49

Originally Posted By: bigwilly
Hi Naz,

The BOM's climate section would be the place to go. You can search by location (Woodside - I don't know the region at all so wouldn't know which adjoining stations would suit) for monthly statistics, which should include pan evaporation.

You might have to do a bit of research to determine the relationship between pan evap. and creek/water body/soil evap.

I have what I was looks for, but thanks anyway smile.

Update:

This video:

Video 3, Streamflow Onkaparinga River, 24th August 2010, 3.20 pm

gives an idea of the difference in volume between the 24th and the 25th, and also the rate of flow. At the end of the video I show the riverbank, which was completely submerged the following day.

Total rainfall 10:55 am on the 20th to 11:15 pm tonight was 77.1 mm. 22.7 of that fell between 5:10 pm on the 25th and 8:20 am yesterday.
Posted by: Seina

Re: Streamflow Observations - 31/08/2010 21:56

Originally Posted By: Surly Bond
The Namoi River is flowing high enough for me to see the water from my window. It has been doing it for days. I am reflecting on how rare this sight has become.
Keepit Dam is filling up now, despite the determination of the authorities to empty it out. They have had it steady at 26% for years, despite 2007 and 2008 having rainfall well above average. I was beginning to think that demand would permanently exceed supply. Now Keepit Dam is up to 51%. It will take a little while to use that up.
The smaller upper storage, Split Rock Dam, which filled completely in winter 1998, but was rapidly used up, and has been steady at 2.6% for as long as I can remember, has more than doubled in volume to 5.9%. That could be used in the twinkling of an eye.

The last I heard the local Mount Bold Reservoir was at around 80% capacity. That could be before or after recent rains…whatever it is now, recent weather events could reduce the stress of supply from the River Murray. High flows also tend to flush the system; leading to a sharp drop in salinity before it starts rising again as flows ease.

There are both pros and cons to these significant flows. A highly-vegetated or dense riparian environment (surround a stream) reduces direct runoff to an appreciable degree. This means reduced flood impact on the local environment and industry, particularly agricultural. Less damage means reduced cost impact. European settlement has undoubtedly had environmental and climatic consequences which may have lead to a greater intensity flushing of surface water systems when knowledge of impact of severe weather events is not reflected in policy.

The immediate consequence may be somewhat subtler, however it is noticeable: that is an intensification of the water cycle (flushing) as a result of reduced intermediary processes (vegetation uptake, soil cohesion, etc.). Water is discharged in greater volume and at a greater rate. Though, some inroads have been made on revegetation, etc. in recent years, which is an encouraging sign. Other consequences which are not necessarily connected with climate change include changes in rainfall/evaporation, evapotranspiration and temperature. I think more emphasis should be placed on studying these things (weather and climate variability) and the massive quantities of data waiting to be analysed before we start letting assumptions fly.

It’s enough to say that the science on weather and climate is not settled.
Posted by: Thunderstruck

Re: Streamflow Observations - 31/08/2010 23:15

Looking good there Carl and I bet you it will be RAGING another 2m higher again after this system, it's going to really burst its banks this time.

TS cool
Posted by: Surly Bond

Re: Streamflow Observations - 01/09/2010 09:44

Cosmic, I wonder if you have data on how often the Onkaparinga floods over its banks? That would put your observations in context.
I think that over-bank flow in Australia tends to come at about the 50-year flood level, that is, the 2% probability of occurrence in any year.
Posted by: Seina

Re: Streamflow Observations - 01/09/2010 22:40

I think the relationship between rainfall and streamflow (and climate) is quite complex along the Onkaparinga River. You may not necessarily get a good correlation between streamflow further downstream (e.g. Verdun/Hahndorf) and rainfall up here. I am aware of some factor which could be playing a role, however my understanding of them is preliminary at this stage; there are many subtle variations and you probably really need to go out in the field and do accurate measurements along the river for calculating variables such as volumetric discharge, etc. Another issue is that you cannot really expect one rain gauge to reflect the flows of a catch of +300 km2, topopgraphic changes or changes in land use, which would effect evapotranspiration. I have attempt a few different methods for sorting out these kind of things, but you really need a whole range of integrated computer software to begin to get a reasonable picture.

The other thing is that, in terms of climate teleconnection, you can sometimes get streamflow-rainfall correlations where a rain gauge several kilometres upstream correlates more reasonably than a closer gauge.
Posted by: Seina

Re: Streamflow Observations - 01/09/2010 23:02

With the exception of 1992, and the Great Flood of 1956 (the greatest flood on record by an absolute mile), the last breach of the riverbank would have been around 1996.

1996: The same year it snowed in the Adelaide Hills smile.
Posted by: Seina

Re: Streamflow Observations - 03/09/2010 16:31

I have a little more time than I thought.

The river the will breach the bank if we get enough rain to increase the river height by about 0.5 metres. Though I suspect if 10-20 mm more is on the way, flooding will become major.
Posted by: Seina

Re: Streamflow Observations - 03/09/2010 18:13

The rain, thunder and lightning started again just after 5 this evening. The river is right up to the bank, and basically flooding in lower-lying areas. It's gradually rising towards minor flooding, however different parts of the river may start flooding at different times. Another metre rise will see the bank breached significantly. The river is 20-30 metres across in places, 2-3 times what it was just 12 hours ago.
Posted by: Seina

Re: Streamflow Observations - 04/09/2010 11:35


IDS20364
AUSTRALIAN GOVERNMENT - BUREAU OF METEOROLOGY
SOUTH AUSTRALIA REGIONAL OFFICE

WARNING FOR MINOR FLOODING
FOR THE UPPER ONKAPARINGA RIVER
Issued at 6:00 am on Saturday, 4 September 2010

1. FLOOD WARNING :
Rainfall in the Upper Onkapringa Catchment has ranged from 30-60 mm in the last
24 hours. Further rainfall of 15-30 mm is forecast to fall during Saturday.
River heights are now below minor flood level. Further stream rises exceeding
minor flood level are possible with forecast rainfall.

Motorists are advised to avoid flooded road crossings.
People are advised to keep away from deep and fast-flowing water.

The situation will continue to be monitored and the next warning will be issued
by midday Saturday.

For up to date information on weather forecasts and warnings, please refer to
the Bureau of Meteorology web site: //www.bom.gov.au/weather/sa/


2. RAINFALL AND RIVER HEIGHT OBSERVATIONS :


Latest river height observations for SATURDAY 04/09/2010 :

Onkaparinga R at Charleston 1.55m
Onkaparinga R at Woodside 1.15m
Onkaparinga R at Oakbank 0.71m
Onkaparinga R at Verdun 2.20m
Onkaparinga R at Houlgraves 5.46m
Onkaparinga R at Clarendon 9.98m

Latest details on river heights and rainfall information are available at:
http://www.bom.gov.au/sa/flood/rain_river.shtml


3. WEATHER FORECAST :
Rain periods are expected to ease to showers around sunrise. Showers may be
heavy at times during the day.

The Onkaparinga River at Woodside was 1.7 at ~4.30 yesterday afternoon, but minor flood level is 2 m. It looks like it didn't breach the bank, but it did get very close.
Posted by: Seina

Re: Streamflow Observations - 10/09/2010 15:55

After experiencing upload problems...

Peak Flow 4, 3rd September 2010, 4,40 pm
Posted by: Seina

Re: Streamflow Observations - 10/09/2010 16:08

Posted by: Seina

Re: Streamflow Observations - 12/09/2010 21:38

The river level in the local Onkaparinga here in the Adelaide Hills appears to have returned to roughly average conditions (in comparison to the 1990s, during which flooding occurred in 1992, 1994 and 1996). It has not flooded significantly in recent days or months, or even years. The latest significant rainfall events over the past 2 weeks (during which we have received 152.6 mm from the 20th of August to the 10th September) have brought flows not seen for 18 years, however I am somewhat sceptical about the significance of the idea that “old patterns” are returning. Relatively speaking I would say we’re tending to more average conditions.

During the early to mid 1990s and leading up to 2000, river flows levels were maintained at sufficient levels that there is a noticeable difference between more recent years and the 1990s. This is not necessarily reflected in weather observations.

I consider the rainfall so far this winter-spring to have broken even with the long-term average; if the long-term average has been exceeded, it’s likely not by much.

Related to streamflow trends, it is quite apparent that evaporation is decreasing by an appreciable quantity annually, while rainfall is gradually increasing. The fact that evaporation, which is a component of evapotranspiration (which is temperature- and radiation-dependent) is decreasing implies to some extent that the moisture already present in the atmosphere is tending (logarithmically) in a similar trend to the near-surface temperature. This can be a somewhat misleading process, as a higher humidity can mean higher near-surface temperatures, which implicates the effects of carbon dioxide as a greenhouse gas.

As the humidity can only increase so much, meaning it has to go somewhere (either be convected to form clouds or be advected due to a pressure gradient), in the absence of significant changes in pressure, on a climatological scale, increased humidity inhibits evapotranspiration (this is explained below). As there is a distinct, appreciable drop in the rate of evaporation (that has lead me to be suspicious that there something else going on with the climate), this implies transpiration is also affected, which means plants are able to retain more moisture.

Given both evaporation and transpiration have a considerable impact on streamflow (and that both occur on any given day, while rainfall does not), this may mean it is not so surprising that flood-like streamflow events become more common in South Australia, and other states. I would however be caution about the suggestion that more flood-like events mean more reliable and consistent rainfall. Many climatological factors appear to point more to a shift in the seasons of up to 2-3 months over a period of 30 years, implying later winter rains. It then possible wet (and cool, for South Australia) conditions could continued well into spring.

Precipitation is likely increasing, regionally, gradually. However globally, this is open to discussion. I do believe the Clausius-Clapeyron relation should not be underestimated in this situation.

As a note of benefit, increasing rainfall and dropping evaporation rates are more evidence in support of climate change, whether natural or man-made, than evidence against it. This is reflected in the change in saturation vapour pressure with change in temperature, and, in many respects, one cannot discount the role of carbon dioxide in these dynamics.

More rainfall means the air has a higher humidity due to the presence of moisture in the atmosphere (mainly as water vapour, but it can also be due to rain). This also means the actual vapour pressure is closer to the saturation vapour pressure (how much moisture the air above the condensation level can hold). If the temperature increases, then the air above the level of condensation can hold more moisture, and the dewpoint will become lower than the actual air temperature. However, carbon dioxide enhances warming by increasing rates of evaporation from the surface and the release of latent heat from the atmosphere (the dewpoint goes up). More moisture in the air enhances the greenhouse effect (warming) due to water vapour. The additional moisture in the air (latent heat) inhibits more and more latent heat from being released in the atmosphere (having a roughly logarithmic effect on temperature increases), and thus the rate of evaporation starts falling on a climatological scale. At the same time, as there is a logarithmic increase in latent heat (driving the saturation vapour pressure up), there is an equilibrium at which the latent heat being released and the moisture-holding capacity of the atmosphere, affected by the water-vapour greenhouse effect, will become constant. This is typically seen at tropical latitudes, but can also occur further north or south. The effect of this equilibrium means the actual temperature will also increase logarithmically in the same sense.

Rainfall increasing means the saturation vapour pressure is being exceeded on a more regular basis; more moisture is being pumped into the atmosphere than it can hold. In theory, in the absence of increasing carbon dioxide in the air, this might not happen, because the released of latent heat would not be as pronounced. That said it may be more understandable why an influence due to carbon dioxide in the atmosphere could lead to trend of slightly increasing rainfall and distinctly reducing evaporation. This still leaves open other possible influences (from the oceans in particular); however, given carbon dioxide is a greenhouse gas, and greenhouse gases are fundamentally responsible for temperature variations, it seems reasonable to keep these things in mind smile.
Posted by: Seina

Re: Streamflow Observations - 27/09/2010 11:58

Originally Posted By: -Cosmic-
Related to streamflow trends, it is quite apparent that evaporation is decreasing by an appreciable quantity annually, while rainfall is gradually increasing.

To be more specific, the multi-decadal annual trend in Class A Pan evaporation for this region has been plummeting since roughly 1940. This trend, in some sense, appears to have an inverse sinusoidal relation with several climate phenomena.

On another note, it is taking rather a long time for local streamflow to fall back to pre-winter levels. The photos below were taken on the afternoon of the 10th of September and this morning.

Streamflow Onkaparinga River, approx. 3.50 pm, 10th September 2010
Streamflow Onkaparinga River, approx. 10.50 am, 27th September 2010

Also of interest:



And



10:40 am: Raining briefly for 2-3 minutes, so there is definitely still plenty of moisture in the air passing through the area. We also recorded 0 deg C as an overnight low on the 24th.

About 125 mm for the month to date smile.

Currently drizzle tending to light rain.
Posted by: Seina

Re: Streamflow Observations - 28/09/2010 16:19

There is something a little strange about the local weather atm. The humidity is high, temperature around 12 C, and pressure around 1014 hPa, and it has been sporadically drizzling with light showers on-and-off all day, and for the past few days. It seems the only thing missing is atmospheric instability, but there is probably even enough of that around as well. I think what is really needed in these sub-tropical-like conditions (for there is be a deluge) is a bit of heating. The temperature certainly seems to be below some threshold, however it continues to threatened to rain, with spits and spots all over the place! All it’s going to take is a little heat in the right spot from long enough and something may happen!

There also seems to be something sus about the recent streamflow peak. The catchment continues to remains mostly saturated!

Edit: Is it just me or is that 1014 hPa lower than all major Adelaide Mount Lofty Ranges pressure measurements? Even Mount Crawford is about 1019?
Posted by: Seina

Re: Streamflow Observations - 29/09/2010 13:49

Re: previous post, rainfall-wise ~ 0.5 mm.

Pictures of Contrast:

Posted by: Seina

Re: Streamflow Observations - 29/09/2010 14:36

Originally Posted By: Surly Bond
Cosmic, I wonder if you have data on how often the Onkaparinga floods over its banks? That would put your observations in context.

In short, rather a lot for the area – somewhere around 60 over a century and a half, when you’re talking about floods in any season.

I could estimate the rainfall for each flood event and from that the streamflow, however I don’t have the computational resources for that kind of analysis, and it would be far more of a long-term endeavour. I would also need streamflow records against which to compare those I estimate to see how reasonable they were, which is not always possible.
Posted by: Seina

Re: Streamflow Observations - 03/10/2010 21:21

A rather large pond a good 25-30 m long and 5-wide is still 1-1.5 m deep.



Paddocks are looking very green and lush.

Had a few thundery drops of rain today, but nothing much else. Temperatures in the 20-25 degree range; pressure about 1007 hPa.

Something that might be of interest:

Significant 24-hour rainfall events of greater than or equal to 50 mm to 31/12/2008 are estimated to have occurred on:

17th of December 1992,
7th of July 1993,
31st of October 1997,
21st of February 2000,
3rd of August 2004.

Significant 24-hour rainfall events of greater than or equal to 40 mm to 31/12/2008 (not including those shown above) are estimated to have occurred on:

30th of August 1992,
8th of October 1992,
18th of December 1992,
6th of June 1994,
19th of April 1998,
18th of October 2000,
8th of June 2001,
7th of September 2001,
20th of February 2003,
20th of June 2005,
28th of April 2007,
16th of May 2008,
14th of July 2008.
Posted by: Seina

Re: Streamflow Observations - 21/10/2010 21:37

It is possible there is a direct relationship between the mean monthly maximum temperature and the total monthly evaporation which is dependent on the latent heat of vaporisation. In other words if you know the mean monthly maximum temperature, in degrees Celsius, you can calculate the total monthly evaporation, in millimetres. Also of interest is what seems to be, on a monthly timescale, the relationship between evaporation and relative humidity, the square of the latter (mean monthly relative humidity) being dependent on the negative of total evaporation, which is in turn temperature-dependent. In other words, increasing humidity acts to inhibit evaporation (I see this as more of a given). A third potential relationship of interest is that between the square root of total precipitation (in millimetres) and the total monthly dry interval (a count of the length of dry periods, in days, for a given month). You simply total the number of consecutive days without rain on the next rain day, and sum the length of these periods to give the total dry interval. A fourth relationship I find very interest, yet do not completely understand as yet, relates streamflow averaged over a given catchment area (in millimetres per day average depth of water) directly to rainfall for the current and previous months. It also relates an exponential function of the total monthly dry interval (to the power of normalised monthly precipitation) directly to the same streamflow observations (in millimetres per month). This rainfall, dry interval, streamflow relationship is applicable on temporal scales ranging from years (which have higher correlations on average) to days (where high correlations are far more difficult to achieve and justify). In fact, in order to model streamflow (in millimetres per month over a given catchment area) against precipitation on a daily timescale, several timescales of greater than a day are considered, and integrated. The exponential function mentioned earlier is then applied this integral to yield the final streamflow proxies to be regressed against the mathematical transformations of the streamflow observations.

As I am now discovering the dependence of evaporation on relative humidity and temperature, and as, on average, there is far more evaporation than precipitation in Mediterranean climate zones, the next step will be to incorporate evaporation in the streamflow model as a modification of the dry interval function (i.e. replacing the dry interval) to improve the accuracy of this method of streamflow modelling, which, to a limited extent, I have found to be useful throughout the Adelaide Hills, in several cases achieving R Squared values of efficiency of between 0.70 – 0.90.

Climatologically, related to streamflow is the SAM (Southern Annular Mode), which is effectively the end point of the physics described above. The SAM is a function of the zonal pressure anomaly between 40 and 65 degrees south of the equator in the Southern Ocean (although different literature mention different latitudinal ranges, so this may not be a definite reflection of what is meant by the SAM).

Using the psychrometric constant which relates the latent heat of vaporisation to total air pressure, this relationship can be compared to the total monthly evaporation (evaporation is dependent on the latent heat of vaporisation, which in turn is required to calculate the mean maximum air temperature mentioned earlier). By taking the product of the psychrometric ratio (the psychrometric constant without using a parameter for pressure) and total monthly evaporation to the power of a constant and comparing with the original psychrometric constant (pressure-dependent), it seems a high-correlation linear relationship can be established between the two variables (assuming empirical values for evaporation and pressure are used). This relationship can then be roughly plotted on the same line graph to show the significance of the impact of the psychrometric ratio. The end result is a better understanding to role evaporation plays in the determination of how the SAM affects the Adelaide Hills, which it does. Despite the open ocean being a good 200 – 300 kilometres from the Hills, it is still able to have an impact on the region through changes in sea-surface temperatures, which affect evaporation, and total air pressure in turn.

Remembering this is all still theoretical…in conclusion to this rather lengthy critique, sea-surface temperatures in the Southern Ocean, which, above the thermocline, are more affected by incident radiation and wind-driven ocean currents than stratified density differences, respond in a lag, reflected in changes a planetary torque (due to the gravitational pull of the Moon/Sun), of about 2.9 partially-inelastic degrees per tidal cycle (which is somewhat more indirectly related to streamflow) through the motions of the Moon and Sun (affecting tides). The angular momentum of the Earth, which is dependent on latitude, is responsible for generating the fundamental elements of the Coriolis Effect. The Large Rossby Waves in the Southern Ocean, to an extent, reflect the integrated effects of multiple lags (the 2.9-degree elastic torque, which overlaps) over periods spanning weeks to months, which can be clearly and consistently seen when atmospheric and oceanic waves (as a function of the position of the Sun and Moon relative to the Earth) are mapped. The period of these waves, according to the mapping, is about 2.2 waves per month (this does not include effects due to the ionosphere). As these pressure waves approach South Australia, evaporation drops, air temperatures drop, and relative humidity increases. Over the zonal area between 40 and 65 degrees south, sea-surface temperatures respond in a lag to changes in atmospheric pressure due to the differences in density between the ocean and atmosphere (about 1000-fold). As air pressure and evaporation go hand-in-hand (the psychrometric ratio), for the sea-surface temperatures to change appreciably, the rate of evaporation needs to increase appreciably, meaning more sunlight needs to reach the uppermost region of the ocean. Once this starts to happen, the ambient air pressure will increase, and with it the temperature and relative humidity (pressure is temperature- and density-dependent, and relative humidity is temperature-dependent). Once the air is humid enough, advection may occur, where horizontal pressure differences are sufficient to result in a reduction or increase in high-to-low air pressure gradients, wherein partially-inelastic shifts occur to equalise pressure differences. These pressure gradients likely first arose duration the formation of the atmosphere many millions of years ago. While pressure gradients in the atmosphere can change in a matter of hours or days, the motion of near-surface ocean waters (due to atmospheric winds) can take months to years over the same spatial scales. Thus, for example, we cannot expect sea-surface temperatures to respond immediately to changes in air pressure, while the opposite (sea-surface temperatures affecting pressure differences through evaporation and relative humidity) seems far more plausible. So:
  • If incident sunlight increases, sea-surface temperatures increase which increases evaporation.
  • Increasing evaporation increases the air temperature.
  • Increasing evaporation decreases the vapour pressure.
  • Increasing evaporation increases the air pressure and horizontal pressure gradients.
  • If evaporation decreases relative humidity increases.
The mechanism for the passage of a lower-pressure weather system appears to be a change in the pressure gradient. A change in the pressure gradient is brought about by a change in temperature (density changes occur within a small range), and a change in temperature is brought about by a change in the rate of evaporation.

To be continued...
Posted by: Seina

Re: Streamflow Observations - 23/10/2010 21:04

In summary:
  • The maximum and minimum daily air temperature could be used to derive the daily evaporation and relative humidity.
  • The daily vapour pressure could be derived from the estimated relative humidity, maximum and minimum air temperatures.
  • The daily mean sea level pressure could be derived from the maximum and minimum air temperatures, daily evaporation and psychrometric ratio as a function of the latent heat of vaporisation.
  • The daily precipitable water (moisture content of the troposphere in millimetres) could be derived from the daily vapour and mean sea level pressures.
  • The daily dewpoint temperature could be derived from the daily vapour pressure.

An example:

Daily maximum air temperature: 23 C
Daily minimum air temperature: 14 C
Daily Evaporation: 2.9 mm.
Daily average relative humidity: 75%.
Daily average vapour pressure: 16 hPa.
Daily average mean sea level pressure: 1017.4 hPa.
Daily average precipitable water: 24.9 mm.
Daily average dewpoint temperature: 14 C.
Posted by: Seina

Re: Streamflow Observations - 25/10/2010 15:38

There may be some climatological significance in rain falling on or near the 28th of January. I know for a fact that during December (Early? Mid?) the Adelaide Hills receive climatologically significant rains.

Edit:
  • A constant to the power of a function of precipitation is proportional to the dry interval.

The 24.2 mm we have received since the 12th of October have not significantly contributed to streamflow. The local river is now nearing levels seen in early winter.

Most indicators suggest we are tending toward a more humid, sub-tropical climate with higher humidity, less evaporation, more precipitation (under humid conditions), more thundery showers and higher dewpoints. Just recently (checking the humidity) the recorded maximum was 90%.

A contradiction to increasing rainfall may be that higher surface air temperatures (due to humidity – the greenhouse effect) mean the atmosphere can hold more moisture, so it may not be so unexpected to get numerous dry periods.
Posted by: Seina

Re: Streamflow Observations - 25/10/2010 15:47

It might also be worth noting that while evaporation is falling, evapotranspiration appears to be increasing. This suggests longer growing seasons and possibly greater plant nutrient uptake. Evaporation has a potentially signficant impact on streamflow magntiude, evapotranspiration more so.
Posted by: Seina

Re: Streamflow Observations - 02/11/2010 16:38

Posted by: Seina

Re: Streamflow Observations - 02/11/2010 17:37

A couple of photos of flooding from the Southern Highlands, New South Wales, in October:

Flooding in the Southern Highlands 1, NSW

Flooding in the Southern Highlands 2, NSW

And Wangaratta, Victoria:

Flooding Near Wangaratta
Posted by: Seina

Re: Streamflow Observations - 07/11/2010 13:20

Originally Posted By: Unstable
I've got a clear view of the upper part of a shower to my south-east which is going along the range and it's well and truly glaciated smile

Yes, started hailing at about 4:50 this afternoon, for about 10 mins smile. Reasonable size hail, probably 3-5 mm across.

Peak winter-spring flow occurred on the 3rd of September, after approximately 57.8 mm fell in a 24-hour period to the morning of the 4th. This is backed up by a CDAS-NCEP/NCAR Reanalysis which shows the latent heat flux peaking during this time for the year. Also, according to the Reanalysis, the pressure dropped to about 990 hPa mid-morning on the 4th of September, and averaged 997 hPa during the day (in-field measurement: 997). 5 days later on the 9th, the pressure was again around 997 hPa (in-field measurement), which occurred during the onset of isolated severe weather conditions. Statistically, the earlier September rains are the most significant for this year (to date).

Although it is becoming increasingly unlikely that another peak in streamflow will occur in the next 2 months that will exceed that for September, I cannot yet rule out a peak occurring in December, after looking over several streamflow histories for the Adelaide Hills. In more recent days, while flow has not increased significantly (if at all), temperatures and humidity and been more conducive to outbreaks of severe weather conditions. The GFS rainfall forecasting model has been somewhat accurate in the last week – it predicted a moderate rainfall for late October leading into early November, which occurred, follow by intermittent smaller rainfall events in the following days (30th to 7th), which has also happen.

On the 31st, we experienced a moderately intense downpour of hail (10-15 minutes of pea-sized hail), possibly with some sleet (not an exaggeration). The temperature trend that followed this event plummeted to such an extend it felt like winter again (very clear fog on the breath). It was an isolated cold snap, possible very isolated, but very sharp and contrasting in terms of the impact had on the surrounding environment (the temperature dropped to perhaps 7-8 C in the mid afternoon, when you would normally expect it to peak). Considering we were averaging day-time maximums of between 17 and 25 degrees, this was definitely outside that range. The most recent pressure low was 996 hPa on the 29th. It's currently 1004.

It is enough to say recent conditions have been conducive to outbreaks of severe weather events, which is another reason why I’m not ruling out a peak in flow next month.
Posted by: Seina

Re: Streamflow Observations - 07/11/2010 13:32

Although it might give more context, the quote in the above post is a button-click error smile.
Posted by: Seina

Re: Streamflow Observations - 10/11/2010 21:58

There is a significant period from 1987 to 1998 during which no rainfall was recorded for Woodside (23829). I have made attempts to fill the missing data on both 9 am to 9 am periods and 12 am to 12 am periods. Unfortunately no corresponding streamflow records exist against which I could compare any streamflow estimates locally; the nearest catchments covering the time period of interest (1970 to present) are Dawesley to the east and Lenswood to the west.

On another note:

It might be worth getting a copy of the History of Significant Flood Events in South Australia, 1836 – 2005. It includes synoptic charts and analyses.
Posted by: Seina

Re: Streamflow Observations - 11/11/2010 20:51

The air pressure hit a new yearly low (from what I can tell) today: 992 hPa. eek. It has been pretty sultry and threatening to rain since mid-afternoon. Was still 25 degrees at 7 pm.

Despite the dry conditions, the river continues to run rather reasonably for this time of year. It's certainly taking a while to dry out - suggests the latent heat is right up, and with it the wet-bulb temperature.

Also we appear to have experienced greater flows to this point this year than we have in previous 2-3 years. The last time we had signficant winter flows was in 2004 and 2005.
Posted by: Seina

Re: Streamflow Observations - 13/11/2010 21:53

The Barometric Pressure Over the Last 24-Hours (Lower Needle)



Streamflow Today and River Conditions:



5.8 mm, good soaking rain smile.
Posted by: Seina

Re: Streamflow Observations - 13/11/2010 22:19

The difference between the streamflow level in the photo above and that about a fortnight ago is barely noticable.

Also, Compare Peak 2009:



With Peak This Year:



Higher this Year…About August-September
Posted by: Seina

Re: Streamflow Observations - 14/11/2010 12:46

Having looked over photographic evidence, I can pretty much confirmed that flooding of the Onkaparinga River Occurred in September 1991 and August 1992. Less well known is a potential flood event which occurred in Septmber 1986.

The change in the landscape between the early 1990s and now is also dramatic.
Posted by: Seina

Re: Streamflow Observations - 23/11/2010 14:56

Estimates for streamflow modelling of the Onkaparinga River based on data 1/1/1974 to 31/12/2009:

Peak flow 2009: 26th of August.

Estimated flow: 0.0313 Mega Litres. (31.3 cubic metres)
Estimated Evapotranspiration: 2.1 mm.
Estimated rainfall: 12.4 mm on the 26th (42.2 mm on the 25th).
Estimated soil moisture store: 191.2 mm.
Estimated groundwater store: 4.4 mm.

Actual flow at Hahndorf: 1237.19 Mega Litres. (1237190 cubic metres)

Highest recorded flow in that period: 30/9/1996:

0.0722 Mega Litres Woodside (72.2 cubic metres)
10,794.58 Mega Litres, Hahndorf. (10,794,580 cubic metres)
Posted by: Seina

Re: Streamflow Observations - 27/11/2010 19:50

A base flow analysis of Hahndorf observations suggests it is a little more difficult to model the Onkaparinga Catchment upstream than shown above.
Posted by: Seina

Re: Streamflow Observations - 28/11/2010 16:36

I have a sneaking suspicion there's another peak in the flow coming...

5.8 mm to midday.
Posted by: Seina

Re: Streamflow Observations - 29/11/2010 15:20

Special Notes:

Onset of Convective Instability (Late Spring):

T: 30 C, RH: 20%, P: 1006 hPa.

Onset of Cool Easterly Winds after Highly Unstable Electric Atmosphere (Late Spring):

T: 35 C..?
Posted by: Seina

Re: Streamflow Observations - 29/11/2010 15:31

16.8 mm since the 24th.
Posted by: Seina

Re: Streamflow Observations - 29/11/2010 20:43

The current synoptic situation is reminiscent of that for the 6th of February 1925, when significant flooding occurred in Adelaide.
Posted by: teckert

Re: Streamflow Observations - 29/11/2010 21:06

You have a map for that date Carl?
Posted by: Seina

Re: Streamflow Observations - 29/11/2010 21:09

Originally Posted By: teckert
You have a map for that date Carl?
Yep, and a descrption smile!
Posted by: Max Record

Re: Streamflow Observations - 29/11/2010 23:36

100mm+ for a locale in Adelaide? Got any crazy dares I can do if that comes off? wink

Places in the Mid North copped that, too:

5 2 1925 Hallett (Ulooloo Railway Siding) 127.0
6 2 1925 Snowtown (Condowie) 108.0
6 2 1925 Terowie (Parnaroo Sect 50) 102.9
7 2 1925 North Adelaide 163.6
7 2 1925 Adelaide (West Terrace) 141.5
Posted by: teckert

Re: Streamflow Observations - 29/11/2010 23:49

lol.... can you share it with us Carl?
Posted by: Seina

Re: Streamflow Observations - 30/11/2010 15:41

Originally Posted By: Max Record
100mm+ for a locale in Adelaide? Got any crazy dares I can do if that comes off? wink

Places in the Mid North copped that, too:

5 2 1925 Hallett (Ulooloo Railway Siding) 127.0
6 2 1925 Snowtown (Condowie) 108.0
6 2 1925 Terowie (Parnaroo Sect 50) 102.9
7 2 1925 North Adelaide 163.6
7 2 1925 Adelaide (West Terrace) 141.5

Those figures are accurate smile...I will have to upload the maps (more than one), so hang on a bit.

GFS Forecast, along with other obs, have held firm for the last few days.
Posted by: Seina

Re: Streamflow Observations - 30/11/2010 15:52



Posted by: Seina

Re: Streamflow Observations - 30/11/2010 15:58

You will notice there's a scribble on the top map near the high centre bottom, I think that's meant to be a front/low.
Posted by: teckert

Re: Streamflow Observations - 30/11/2010 15:59

OMG.... thanks Carl... How/where did you get them?
Posted by: Seina

Re: Streamflow Observations - 30/11/2010 16:02

Honours Research a few years back...flood history 1836-2005 smile.
Posted by: Seina

Re: Streamflow Observations - 30/11/2010 16:05

eek @ the forecast!
Posted by: Seina

Re: Streamflow Observations - 30/11/2010 17:00

Originally Posted By: -Cosmic-
I have a sneaking suspicion there's another peak in the flow coming...

5.8 mm to midday.

Special Notes: 4:28 pm CDT

Subtle Change in Low Flow at a two specific locations:

3 days of observations:

28: Higher.
29: Higher Again.
30: Lower than 29th.

Possible groundwater/spring influences.

First rain drops.
Posted by: Seina

Re: Streamflow Observations - 02/12/2010 17:25

We have another peak for the year grin! River has risen dramatically since 3:30 pm.
Posted by: Seina

Re: Streamflow Observations - 02/12/2010 21:39

I have more than 10 photos to load, will that work?

...Covering Prediction to Observation smile!
Posted by: Seina

Re: Streamflow Observations - 02/12/2010 21:53

Ok, try again...

These are only Photos, a Snapshot, but they may give some perspective smile

Streamflow Observations, 28th November 2010



Streamflow Observations, 29th November 2010



Approaching Thunderstorm and Rainbow, 30th November 2010



Approaching Thunderstorm, 1st December 2010



Streamflow Observations, 1st December 2010



Streamflow Observations, Afternoon, 1st December 2010



Rapid Thunderstorm Development, 2nd December 2010, 3 pm



Underneath the thunderstorm, 2nd December 2010



30 minute downpour, 2nd December 2010: 28.3 mm



Runoff from thunderstorm, 2nd December 2010



To be continued...
Posted by: Seina

Re: Streamflow Observations - 02/12/2010 21:54

The Flash Flooding Bit:

Streamflow Increasing, 2nd December 2010



Streamflow Increasing Even More, 2nd December 2010



An example of flash flooding of the Onkaparinga River:



That was something grin!
Posted by: Seina

Re: Streamflow Observations - 04/12/2010 17:55

Pressure is 989 hPa @ 5:25 pm.
Posted by: Max Record

Re: Streamflow Observations - 04/12/2010 22:42

Wow! Love those maps! And good timeline you've got there. smile Would love for that to happen here.
Posted by: Seina

Re: Streamflow Observations - 07/12/2010 09:35

Pressure and rainfall since 1st Dec:

999 28.3 T/S
998 0
996 0
992 3.1 T/S (989 @ 5:25 pm)
989 12.4 T/S*2 (12.1 T/S*2)
990 2.9 (current)

T/S: Thunderstorm.
Posted by: Seina

Re: Streamflow Observations - 07/12/2010 22:29

Pressure 987 (10 pm), was 986 (5:20 pm), 16.3 mm early afternoon from T/S.

29.5/18.5, high humidity.

Flooding in North Adelaide (covering half 2-lane highway, foot deep). Lights on amber at at least one major intersection.

Now: (8:30 to 10 pm+) very frequent close lightning, light rain.
Posted by: Seina

Re: Streamflow Observations - 08/12/2010 13:51

I guess you could say that when a sneaking suspicion like this actually eventuates, all you can really say is stuff happens smile.

Will have to reorganise some photos again...(re above errors)!
Posted by: Seina

Re: Streamflow Observations - 08/12/2010 14:12

Originally Posted By: -Cosmic-
I have a sneaking suspicion there's another peak in the flow coming...

1st-8th (?)...
Posted by: Seina

Re: Streamflow Observations - 08/12/2010 17:10

Originally Posted By: -Cosmic-
Originally Posted By: -Cosmic-
I have a sneaking suspicion there's another peak in the flow coming...

1st-8th (?)...

At this point...I think not.
Posted by: Seina

Re: Streamflow Observations - 09/12/2010 11:07

Posted by: Seina

Re: Streamflow Observations - 12/12/2010 14:14

First Major Downpour, Afternoon 2nd Dec 2010
Streamflow just after thunderstorm
Streamflow an hour later (short video)

First thunderstorm to dump 44 mm over 24-hour period over Oakbank, Afternoon, 2nd Dec 2010
Posted by: Seina

Re: Streamflow Observations - 12/12/2010 14:34

Streamflow, Early Morning, 8th Dec 2010, Peak Flow
Posted by: Seina

Re: Streamflow Observations - 12/12/2010 14:48

And lastly, for this event…

Temperature, Pressure and Rainfall 1st-8th Dec 2010

22 11 1000 3
25 13 999 28.3
32 10 998 0
35 21 996 0
27 19 992 3.1
29 14 989 12.4
30 19 986 21.4
23 15 993 18

Currently: …3.3 mm in the last 3 days.
Posted by: Seina

Re: Streamflow Observations - 17/12/2010 21:08

Streamflow-based Prediction, 17th Dec 2010, 5:30 pm ACDT:

21 mm 19th-20th Dec 2010.
Posted by: Seina

Re: Streamflow Observations - 20/12/2010 15:56

Originally Posted By: -Cosmic- (naz)
Streamflow-based Prediction, 17th Dec 2010, 5:30 pm ACDT:

21 mm 19th-20th Dec 2010.

14.9 mm 12 am 19th to 9 am 20th Dec 2010.

Small change in flow level 19th-20th.

MTD: 109.7. Avg: 32.2.
Posted by: Seina

Re: Streamflow Observations - 21/12/2010 18:27

With the exception of some smallish sharp peaks in flow in 2000, 2001 and 2004 and 2010,it seems the current drought conditions for the hills (streamflow-wise) started in 1997.

2010 is the wettest year (streamflow-wise) since 1996.

This year's peak seems to be more than double the magnitude of that of 2004. 1996 is several times the magnitude.
Posted by: Seina

Re: Streamflow Observations - 22/12/2010 16:24

Now this is beginning to push it:

December MTD (2010): 112, Avg: 32.2 mm.
Posted by: Seina

Re: Streamflow Observations - 23/12/2010 14:58

Comparison of Long-term Monthly Rainfall Totals, 2004, 2005 and 2010 (22nd), and Pressure, RH 2010
Posted by: Seina

Re: Streamflow Observations - 24/12/2010 14:22

There is going to be a spike in rainfall soon. I'd rather not say how much.
Posted by: Seina

Re: Streamflow Observations - 24/12/2010 22:17

Surface Pressure peaked yesterday at 1012 hPa, after being 1006 hPa the previous day. It's currently 1000 hPa and falling. Temperature peaked at 31. Humidity has increased sharply - you can smell it.
Posted by: Seina

Re: Streamflow Observations - 25/12/2010 22:40

I believe I now have a sense of the atmospheric conditions conducive and required for humid summer rainfall. 10 pm Pressure: 996 hPa, Rain: 0.1 mm (during the morning) + trace around midday.
Posted by: Seina

Re: Streamflow Observations - 25/12/2010 23:18

In due coarse I may have up an explanation of the streamflow-rainfall connection smile where pressure, temperature and RH are involved.
Posted by: Seina

Re: Streamflow Observations - 26/12/2010 12:57

Temperature reached 34 degrees yesterday (25th) - this was expected. It is likely temperature will reach 37 degrees for NYE smile.

On my prediction, it has not actually come to fruiton yet...

It looks like our max was 19 today, currently falling.
Posted by: Seina

Re: Streamflow Observations - 27/12/2010 11:58

Originally Posted By: -Cosmic- (naz)
On my prediction, it has not actually come to fruiton yet...

Because it's meant to take 5-6 days, give or take (from the 24th). Will see smile .
Posted by: Seina

Re: Streamflow Observations - 31/12/2010 20:53

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
On my prediction, it has not actually come to fruiton yet...

Because it's meant to take 5-6 days, give or take (from the 24th). Will see smile .

In the last few days the pressure has plummeted from around 1012 hPa to 988 hPa this evening (that's a 24 hPa difference), a top of 37 C, now about 28 C. The pressure is in the "rain" area and approaching "much rain."
Posted by: Seina

Re: Streamflow Observations - 01/01/2011 12:35

Pressure back up to around 1000, RH spiked last night, temp currently 27...

Happy New Year to All smile!

And may the streams flow well where needed for 2011!
Posted by: Seina

Re: Streamflow Observations - 01/01/2011 12:41

Originally Posted By: -Cosmic- (naz)
The pressure is in the "rain" area and approaching "much rain."

Just to clarify, this happens before signficant rain.
Posted by: Seina

Re: Streamflow Observations - 01/01/2011 23:38

In case anyone is wondering why I might be being so definite about my predictions/observations, rather and using probability and being less certain it is because I'd rather be either very accurate or very inaccurate rather than beating around the bush.

So far, based on observations, the predictions I've been making about conditions conducive to rainfall rather than actual rainfall (hence not predicting amounts), the pressures humidities and temperatures have been in sync and occurred on 2nd Dec 2010, 7th-8th Dec 2010, 25th Dec 2010, 26th Dec 2010 and today. All days recorded at least a trace of rain, which is encouraging.

The rain on the 19th-20th Dec was more certain.

Today we experienced a downpour lasting all of 30 seconds around 1.30 pm.
Posted by: Seina

Re: Streamflow Observations - 02/01/2011 12:28

The relationship between rainfall and streamflow is non-linear on the daily timescale, and depends on the “memory” of the system months in advance of the day on which streamflow is recorded. Capturing the magnitude of streamflow accurately is difficult due to numerous factors including:
  • Changes in osmosis (where vegetation takes moisture from the soil);
  • Evaporation (directly from streams, from the soil and pools of water including dams and ponds);
  • Transpiration from plants (dependent on vegetation cover and vegetation type);
  • Soil structure (which way and how water flows in the soil);
  • Porosity (the volume of pore spaces with air or water);
  • How much water soaks directly into the soil, and how much reaches how deep before residing in underground aquifers;
  • How much direct run-off soaks into the soil after travelling a given distance over land;
  • How much direct run-off is lost through evaporation;
  • How much direct run-off is lost through osmosis after rain.
Fundamentally streamflow is dependent on rainfall and evapotranspiration on multiple timescales. How much evapotranspiration there is significantly affects the memory of a stream system. There is always some evaporation even if there is no measureable rainfall. Potential evapotranspiration calculated using the Penman-Monteith Formulation typically becomes less during winter months and increases into and during summer. This is primarily due to changes in cloud cover, humidity and vegetation soil-moisture uptake. Pressure is also typically consistently higher during winter and sporadically higher during summer, meaning differences in pressure on a daily basis are greater leading into and during summer and comparatively smaller during winter.

Sub-Note:

It is understood that what happens in the Southern Ocean many, many months ago affects the climate dynamics locally (particularly rainfall) in South Australia through changes in the SST and pressure, and potentially to a reduced extent areas of the Northern Territory, Central and Western WA, parts of Queensland and South-western Victoria. This is quite apart from the ENSO phenomenon which is based in the Pacific, although the two may overlap/interact to some extent.

Of significance to this ENSO-Southern Ocean relation is likely the Northwest Cloud band, extending from the North-western-most corner of South Australia to Southern Victoria. This feature has become more prominent in recent years, bringing with it much moisture from the tropics and sub-tropics. During summer, this moisture is known to contribute to flooding and flash-flooding in numerous South Australian Regions. The Northwest Cloud band is also associated with the passage of various frontal systems across Southern Australia, and is also noticeable in their absence when high-pressure cells are present in the Bight.

The Southern Ocean SST-pressure phenomena can be associated the rainfall in this region through the development of North-westerly winds and large changes in regional pressure. However, unlike atmospheric events which can take days to develop, oceanic phenomena may take several years, which potentially gives a huge lead-time to forecasting rainfall in South Australia and various other regions.

I would urge more research be conducted into these aspects of climate and their impacts on microclimatic conditions, as there are potentially significant implications for water management and natural disaster mitigation both within a beyond South Australia.

Continuing:

The mean pressure for 2010, reduced to mean sea level standard, accounting for vapour pressure, was about 1007 hPa. The low was 982 and the high, 1026. The highest maximum temperature was 37 degrees Celsius on the last day of the year, the lowest 10; the corresponding high and low minimums were 22 (Dec 31st) and 0. The average estimated relative humidity was about 73%. The humidity reached 100% on 209 days total. On 351 days, the pressure was greater than 1000 hPa, and from around the 2nd of December, there is quite a remarkable drop in the pressure; on 16 occasions the pressure was below 1000 hPa. Total rainfall for 2010 was 825.3 mm, about average. The highest-recorded daily total was 55.1 mm recorded on the 3rd of September.

Streamflow in 2010 was about average, possibly a little higher than 2009, and most definitely the highest since 1998.

Observations for likely rainfall events:
  • Pressure starts increasing (long-term 3-5 days out); streamflow increases slightly;
  • Humidity remains stagnant; does not change much and is relatively low;
  • Pressure starts falling (2-3 days out); increasing sporadic wind gusts; streamflow is falling;
  • Humidity increases sharply within 24 hours of rain falling, increasing solar heating (during the day);
  • Temperature starts dropping and must drop for there to be rainfall;
  • Temperature drops locally and sporadically in vicinity of turbulent/unstable atmospheric conditions;
  • Mammatus, virga, altocumulus, visible turbulence hours to minutes before rain;
  • Pressure falls at a slower rate than temperature (hPa vs. deg C); this must be noticeable – pressure must lead temperature change. As a rule half the pressure change constitutes how much temperature may change. This is inevitably accompanied by a wind change;
  • As the temperature falls it is accompanied by a spike in humidity in vicinity of turbulent/unstable atmospheric conditions, because cooler air can not hold as much moisture;
  • Surface heating can be interrupted by cloud cover;
  • If heating (evapo-transpiration) accompanies spike in humidity with the pressure and temperature changes, conditions are more conducive to sporadic rainfall/downpour. Less means more rain rather than intermittent showers.
  • An increase in local humidity implies lower to middle-level troughs (I counted 7 local troughs to the 25th).
  • More evapo-transpiration means more moisture in the air, which means either the temperature is inhibited from falling faster than pressure (less rain, higher pressure) or more unstable atmospheric conditions with higher temperature (summer rain – convection).
  • Stagnant heat/no wind induces active heat/wind if pressure is falling.
  • Rain falls dependent on the difference in drop of pressure vs. drop of temperature.
  • Humidity must be at threshold (yet to be determined, though I suspect 80% locally).
  • Humid conditions must be noticeable, either by smell or less transpiration/more perspiration, etc.
The important thing about making short-term rainfall forecasts using streamflow observations (in this situation) is that any changes in flow behaviour must be noticeable over a period of 2-3 days.

In the case of the most recent downpour, flows in parts of the river first started to increase towards NYE (over a 2-3 day period from 27th-29th, then started dropping 30th-31st). The most noticeable changes were for the prediction of rain on the 2nd of December.
Posted by: Seina

Re: Streamflow Observations - 07/01/2011 14:12

A more organised update:

Thunderstorm Develops, 6th December 2010, 3.22 pm and 3.37 pm, Looking North




Height of December 2010 Flash Flood, 7th and 26th, Looking Downstream, Contrasts




Height of December 2010 Flash Flood, 7th and 17th, Looking Upstream, Contrasts 2




Pressure, 31st December 2010, 7.30 pm



Special Note:

Pressure Stats:

28th Nov: 1012, Temp: 22/13
2nd Dec: 999. Rain (3-4 days from 28th), Temp: 25/13
5th Dec: 992. Rain (2-3 days from 2nd), Temp: 27/19
10th Dec: 1005. Rain (3 days from last rise), Temp: 19/10
11th Dec: 997. Rain (1 day from 10th), Temp: 17/11
13th Dec: 1002. (2 days from 11th), Temp: 27/12
14th Dec: 990. (15th, rises slightly, Rain). (1 day from 13th), Temp: 27/9
17th Dec: 994. Rain (3 days from 14th), Temp: 20/12
23rd Dec: 1012. (4 days from last fall), Temp: 27/10
25th Dec: 997. Rain (28th, drops slightly, No Rain). (2 days from 23rd) 25th Temp: 34/11, 28th: 29/6
30th Dec: 1012. (5 days from 25th), Temp: 36/18
31st Dec: 988. (1st Jan, rises slightly, Rain), Temp: 37/22
3rd Jan: 1005. (4 days from 31st), Temp: 23/10
5th Jan: 997 (2 days from 3rd), Temp: 23/13
6th Jan: No Rain and still dropping, Temp: 34/9
7th Jan: 992 (2 days after 5th), Temp: /16…
Posted by: Seina

Re: Streamflow Observations - 10/01/2011 12:22

Looks like there might be some serious rain on the way this Thursday (between 110-120 mm) eek ... runoff also looks to be substantial - about 1.3 mm spread over the catchment area (of several km).

The pressure is probably going to plummet again quite sharply. When I say plummet, the pressure starts falling typically towards the 13th, then on the 13th it nose-drives, and recovers to start rising again.

Pressure here as been hovering around 996-1000 hPa for the last 3 days. Recorded 0.7 mm on Sunday (the 8th). Pressure dropped to 988 just the day before.

And a very interesting phenomenon on the 8th, low-level gusty stratus-type clouds moving swiftly northwest while higher cirrocumulus cloud moving in the opposite direction. The wind direction was again easterly yesterday.
Posted by: Seina

Re: Streamflow Observations - 10/01/2011 12:45

I'm a bit suspicious about the current weather patterns, they suggest:

=> Dominant inland trough of some kind moderating max/min temperatures.
=> Influences from the sub-tropical and tropical infeeds.
=> 13th - Low forms between approximately Ceduna and Cape du couedic and penerates inland to the mid north causing an abrupt shift in temperatures and a sharp temperature gradient orientated north-south.
=> That little stationary puff of cloud on the satellite images in the middle of the Bight.
Posted by: Seina

Re: Streamflow Observations - 10/01/2011 21:16

Bloody hell...only 3 days out and the forecast rain for the 13th has tripled eek eek !

Forecast now has two peaks for streamflow - 10 mm over catchment area on 13th and 3.5 mm nearing the 14th. Pressure here is crawling towards 990.

I am expecting a pressure of around 977 on the 13th at this stage. Temperature probably won't change much, but humidity will. And I'm not ruling out the possibility of it arriving sooner.
Posted by: Seina

Re: Streamflow Observations - 10/01/2011 21:52

I'm staying with 12th-14th for now smile .
Posted by: Seina

Re: Streamflow Observations - 10/01/2011 22:13

Just had a look at the MSLP prediction for the Australian Region. If I'm not mistaken that's part of a monsoon trough making it's way south across the continent to be situated where the high is atm (13th-15th). The main routes south are through Perth and Adelaide areas. I've never seen that happen before. Can anyone offer an explanation??? And then there's the East Coast Floods!??

I'm looking at this:

display plot gfs_master_00z.ctl, PRMSLmsl 1000, 03Z10jan2011 to 12Z17jan2011

http://nomad3.ncep.noaa.gov/cgi-bin/pdisp_gfs0.5.sh?dir=%2Fgfs20110110
Posted by: Seina

Re: Streamflow Observations - 10/01/2011 22:26

Check out the line of activity from the Pacific into the SE QLD/NE NSW region, ok...

Where's a frickin weather folklore book when you need one!

On a more serious note, this is sus!
Posted by: Seina

Re: Streamflow Observations - 11/01/2011 12:55

The forecast seems a little more realistic and less sus today, around the 18-mm mark. Been drizzling here this morning, but probably not enough to really affect flows.

77% Humidity, 19 C, and barely a trace of rain, even though the pressure has risen by 4.

To be honest, I still think we could looking at a dumping, up to 50 mm.
Posted by: Seina

Re: Streamflow Observations - 11/01/2011 15:00

If anyone has any idea why the monsoon trough is predicted to head south, I'm all ears smile . From what I can tell, the trigger looks to be a passing frontal system from the west.

It is very interesting though with the rain over in Queensland, that it has not stopped yet and that there is so much of it. I suspect it is going to continue for some time yet (perhaps not such a good thing). And probably not just due to ENSO influences; the monsoon trough to the north and northeast probably needs to start moving, which is what the MSLP prediction still says it will do.
Posted by: Seina

Re: Streamflow Observations - 11/01/2011 16:45

Unless things start changing signficantly, my thinking is we could start to consider battening down the hatches (Adelaide Hills).

Latest Obs: Rh: 77%, Max/Min 19/18, P: 996.
Posted by: Seina

Re: Streamflow Observations - 12/01/2011 12:45

Ok, it's gone up again...forecast 70 mm tomorrow.

Edit: Really beginning to think some serious rain is not out of the question. Forecast map has some rather large and interesting totals for the South East 06Z 13th Jan 2011.
Posted by: Seina

Re: Streamflow Observations - 12/01/2011 12:59

Edit time ran out...

The trough to the north is starting to move, and the system to the west is on its way.
Posted by: Seina

Re: Streamflow Observations - 12/01/2011 13:22

Read and heed: SA Flood Watch!
Posted by: Seina

Re: Streamflow Observations - 14/01/2011 15:19

Rainfall for yesterday was 14.7 mm.
Posted by: Seina

Re: Streamflow Observations - 14/01/2011 15:40

Modelling of streamflow on a scale of less than 0.1 mm runoff per square metre catchment area in these sorts of drying conditions does not seems appreciable atm. Most of it has been lost to the soil or evaporation long before it reached the river. The increased runoff is there, it's just not substantial.
Posted by: Seina

Re: Streamflow Observations - 14/01/2011 15:49

The local pond is also completely empty. I don't think it has a clay layer beneath it so it's probably permeable to the soil below.

For those interested, they may be the possibility of thundery showers this afternoon.
Posted by: Seina

Re: Streamflow Observations - 15/01/2011 19:46

0.2 mm to 9 am today, 9 am RH: 68%.

Temp: 36/9...
Posted by: Seina

Re: Streamflow Observations - 16/01/2011 18:42

Pressure is a bit all over the place atm, 1000 9 am yesterday, 992 7 pm, 998 12 pm today, and 994 at 6. Get the feeling it’s slowly rising and might start falling more after the 18th. Will probably know in a few days time.

Normally in more summer months, the pressure is lower on average and more variable, and during winter, higher and less variable (if I've got that right) -- more affected by air density/humidity possibly. So if the pressure is going up, we can expect more rain in summer (if the temperature is going down), and vice versa in winter...or something like that lol.

I’m kinda thinking it’s going to rain on the 18th (Tuesday), which is about 2 days away.

Humidity seems to be going up and down like a yo-yo.

Temp was 32 today.

Interesting, forecast seems to have lower temp for today, under 30 (26 ish)...and then til the 20th.
Posted by: teckert

Re: Streamflow Observations - 16/01/2011 20:15

Hey Carl.

Sorry to interrupt your monologue here but wanted to ask a couple of things.
What is pointing you to rain on Tuesday? I cant see any sign of precipitation coming apart from a weak trough on Thursday.
Secondly, where are you getting your observations from? Barometer and temp? It only got to 27C today in the city, probably slightly cooler in the hills.... not a chance it got as hot as 32C up there....
Posted by: Seina

Re: Streamflow Observations - 16/01/2011 21:32

Originally Posted By: teckert
Hey Carl.
Sorry to interrupt your monologue here but wanted to ask a couple of things.
What is pointing you to rain on Tuesday? I cant see any sign of precipitation coming apart from a weak trough on Thursday.

I use a combination of in-field streamflow observations at several points along the Onkaparinga, GFS (AVN) model outputs on a 3-hourly timescale (shows perhaps 1 mm on the 18th at this stage, but admit I have to be careful there), and a streamflow model I developed during and after my honours research, which uses rainfall to estimate flows and groundwater recharge/discharge.

Originally Posted By: teckert
Secondly, where are you getting your observations from? Barometer and temp? It only got to 27C today in the city, probably slightly cooler in the hills.... not a chance it got as hot as 32C up there....

I have a calibrated aneroid barometer to the nearest hPa estimated based on surrounding BoM sites (Mt. Crawford, Adelaide, etc.), a max/min temperature thermometer which I have been taking consistent daily readings from and which I note whenever there are surrounding environmental changes, and another relative humidity-max/min temperature sensor/gauge to compare against the first temperature readings as a reference point.

Our temperature observations are often reflected in those from Mt Barker, and probably even more so out towards Murray Bridge. It is not uncommon for it to be hotter here than it is in town on some days. We also don’t get as much of the sea breeze from the west and humidity can be higher due to orographic uplift and vegetation cover (along with the odd morning fog).

Hope that helps smile .
Posted by: Seina

Re: Streamflow Observations - 16/01/2011 21:41

Atm, given what's been happening in other states recently, I figured it might be worth keeping an eye on these things for a while...however I can't garauntee this thread continuing indefinitely without some kind of feedback/questions, etc smile .
Posted by: Seina

Re: Streamflow Observations - 16/01/2011 21:52

To be honest I don't really need to be doing this because the vast majority of the research, etc. I do is not on here.
Posted by: teckert

Re: Streamflow Observations - 16/01/2011 22:43

no worries...
Yer I'm surprised you dont get more people commenting.... I occasionally have a read.... moreso when I know there has been significant falls in the hills.
Posted by: Seina

Re: Streamflow Observations - 22/01/2011 21:17

I'll probably only be doing major weather event from now on, if any...

Of recently there's been little if any sign of rain, simply moderate temperatures.

The only thing that has piqued my curiosity was the synoptic chart from the BoM, which seems to be similar to an event in mid-summer 2006-2007. Something might happen from it, maybe not.

To be quite frank, when you consider all the question we ask about how come we're not getting our weather/climate forecasts right, or how little we understand this or that, you would have thought people would put more resources into that stuff.

Perhaps people are not so serious when they ask the questions...it would be interesting to find out.
Posted by: Seina

Re: Streamflow Observations - 25/01/2011 17:22

Originally Posted By: -Cosmic- (naz)
Of recently there's been little if any sign of rain, simply moderate temperatures.

The only thing that has piqued my curiosity was the synoptic chart from the BoM, which seems to be similar to an event in mid-summer 2006-2007. Something might happen from it, maybe not.

Perhaps it might be worth factoring in smile . Pressure is now 992 - last time it was that low it rained.

There are times when I wonder whether there will be a "snapback" to the conditions of the early-to-mid 1990s or 1970s.

The one thing I can gauge at the moment is that streamflow in the Adelaide Hills may be increasing.
Posted by: Seina

Re: Streamflow Observations - 31/01/2011 12:09

I'm going to mention this anyway, just in case...

About a month ago there were signs the temperature could potentially plummet to trend below 25 C this summer. While I'm still fairly uncertain about what's actually going to happen, I would say it's still possible.

Temp and pressure trends seem to have been a bit sus recently...temp 41 yesterday, 37 the day befoe, and hovering between 28-31 4 days straight prior to that. In other words it jumped 6 degrees outright in one day.

Pressure dropped consistently from 1012 to 1004 and 1010 to 998 2 days (28th and 29th). Was sitting on 994 yesterday and now still about the same.

Long-term outlook is difficult, but I would guess temperature plummeting after the 3rd-5th of Feb and significant rain event.
Posted by: Seina

Re: Streamflow Observations - 31/01/2011 12:23

The reason yesterday's max seems so significant and slightly ?? is because nothing in the last 395 days gets close to it.
Posted by: Seina

Re: Streamflow Observations - 31/01/2011 13:41

Special Note 31-1-11:

=>Serious amounts of energy in the atmosphere, and being released by it. ???

Global warming, no...potentially something else...
Posted by: Seina

Re: Streamflow Observations - 31/01/2011 15:33

Originally Posted By: -Cosmic- (naz)
Special Note 31-1-11:

=>Serious amounts of energy in the atmosphere, and being released by it. ???

Global warming, no...potentially something else...

Another 40-degree day (3 pm).

Just as a note of benefit, if I understand this correctly, specific humidity trends inversely with surface pressure.

Current Pressure: 990, RH: <20%. [Think I might get some photographic evidence of pressure.]
Posted by: Seina

Re: Streamflow Observations - 01/02/2011 09:31

Originally Posted By: -Cosmic- (naz)
Another 40-degree day (3 pm).

Correction: 41 C. Pressure 986 @ 8:30 pm.

GFS is forecasting are major rain event 7th-8th.
Posted by: Seina

Re: Streamflow Observations - 01/02/2011 18:29

Re: Last Special Note (31-1-11)

There's forecast (BoM, ACCESS) a frontal system passing in the Southern Ocean, heading north. It looks like this will interact with remnant moisture from the passing Severe TC Yasi to form new lows between SA and VIC, and a potentially a series of lows across the top end associated with the Monsoon Trough. The result is potentially heavy, consistent rainfall for a period of perhaps a day or two on the leading edge of the front/NW cloudband interaction (40-50 mm).

Temperature will be affected significantly for this period (25 C or lower), the pressure will rise in the wake of the passing frontal system, and expect the (specific) humidity to plummet sometime around the 7th-8th, followed by a sharp increase towards the 9th.

Rainfall is likely to be heaviest round 7th-8th, at a guess.

I believe there could also possibly be another cyclone forming in the wake of Yasi...however again this is too early to tell.
Posted by: Seina

Re: Streamflow Observations - 01/02/2011 18:42

Forgot to add, to clarify, specific humidity is likely to reach a low at the same time pressure peaks, before or during rainfall.
Posted by: Seina

Re: Streamflow Observations - 01/02/2011 22:58

Originally Posted By: -Cosmic- (naz)
I believe there could also possibly be another cyclone forming in the wake of Yasi...however again this is too early to tell.

GFS (MRF) Forecast mrf20110201.ctl
PRMSL 1000
00Z01feb2011 to 12Z16feb2011, Animation

http://nomad3.ncep.noaa.gov/cgi-bin/pdisp_mrf_dir.sh?dir=%2Fmrf20110201

PRMSL 00Z12FEB2011


...to restate the special note 31-1-11, "potentially something else..."
Posted by: Seina

Re: Streamflow Observations - 02/02/2011 16:52

Originally Posted By: -Cosmic- (naz)
Long-term outlook is difficult, but I would guess temperature plummeting after the 3rd-5th of Feb and significant rain event.

What I didn't mention is rain was forecast for the 3rd-5th...as well, only the 7th-9th seemed more signficant at the time.

Pressure: 990, RH: 27%, Temp: 34.

Edit: This (major rain) might be happening earlier than expected.
Posted by: H'Bay Qld

Re: Streamflow Observations - 02/02/2011 16:53

Didn't Hayden Walker predict another cyclone around that time?
Posted by: Seina

Re: Streamflow Observations - 02/02/2011 16:58

Originally Posted By: H'Bay Qld
Didn't Hayden Walker predict another cyclone around that time?

Not familiar with that...but it sounds plausible smile...patterns appear to be shifting.

One thing seems clear though, in part, what was going to happen in a weeks time is happening now.
Posted by: Seina

Re: Streamflow Observations - 03/02/2011 15:40

Trace of rain since 11:55 last night...probably more to come - pressure back up to ~1000 hPa.
Posted by: Seina

Re: Streamflow Observations - 03/02/2011 16:03

There is some very interesting rain development going on in SA...potentially associated with (Severe ?) TC Yasi.

Edit: At this time I don't think it's appropriate to say what I thought was going to happen (now) in QLD, but it's impact on our weather is important (for us).
Posted by: Seina

Re: Streamflow Observations - 03/02/2011 16:15

SA Flood Watch
Posted by: Seina

Re: Streamflow Observations - 04/02/2011 13:41

11:20 am: P: 994, T: 30 (Low: 20), RH ~50%. Sultry
1:10 pm: P: 991, T: 32, RH, ~45%.
Posted by: Seina

Re: Streamflow Observations - 05/02/2011 15:26

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Long-term outlook is difficult, but I would guess temperature plummeting after the 3rd-5th of Feb and significant rain event.

What I didn't mention is rain was forecast for the 3rd-5th...as well, only the 7th-9th seemed more signficant at the time.

Pressure: 990, RH: 27%, Temp: 34.

Edit: This (major rain) might be happening earlier than expected.

Right time…wrong place (or least, right area re: SA Flood Watch and Victoria).
Posted by: Seina

Re: Streamflow Observations - 06/02/2011 13:23

1:10 pm CDT pressure should have been 992, not 991.
Pressure @ 12:50 pm CDT (today), 1018 hPa eek...?
Posted by: Seina

Re: Streamflow Observations - 09/02/2011 12:34

Provided the pressure continues on its present trend (down from 1018 hPa), the rain event 9th-11th Feb or thereabouts seems more likely to closer we get to those dates (up to 20 mm) (GFS). The pressure is currently slightly lower than MSLP (1012 hPa).

However that doesn't detract from the fact the river level has been deteriorating since about the 19th of the 12th last year (lost a good half a metre to a metre in places).
Posted by: Seina

Re: Streamflow Observations - 10/02/2011 14:33

The temperature is too high (29) the RH too low (~30%), and pressure continues to fall (~999)...and the river has lost another quarter to half a metre...winds are picking up,...and my initial thinking is rain/showers, with a dump not out of the question!
Posted by: Seina

Re: Streamflow Observations - 11/02/2011 12:10

Originally Posted By: -Cosmic- (naz)
The temperature is too high (29) the RH too low (~30%), and pressure continues to fall (~999)...and the river has lost another quarter to half a metre...winds are picking up,...and my initial thinking is rain/showers, with a dump not out of the question!

Pressure has risen, 998 from 994, RH: ~90%, temp ~20. 1 mm in the 8 hours to 10:20 am (light showers), 7 mm to 11:30 am (thunderstorm and downpour 3 mm in 20 mins).

Impact on streamflow is minimal (river ponds are too disconnected). If anything the size of puddles has increased.
Posted by: Seina

Re: Streamflow Observations - 13/02/2011 16:03

Another .5 mm brings it to 8.5 mils total.

Not expecting another rain event of this kind (or a significant rain event) for another 3-4 days.
Posted by: Seina

Re: Streamflow Observations - 13/02/2011 16:18

Barometer is smack bang on MSLP (fixed needle) (~1013): 3:40 pm.

Keeping an eye on LWT (Long-wave Trough).
Posted by: Seina

Re: Streamflow Observations - 14/02/2011 12:09

Supplementary Note:

All these anomalies that seem to be occurring in the observations are threatening to culminate in something…

[I'm talking within a year].

P: still 1013 hPa.
Posted by: Seina

Re: Streamflow Observations - 16/02/2011 11:30

GFS is predicting what looks like a signficant streamflow event for the 18th Feb, flow is expected to be 0.5 mm per square metre in the region (2 days out).
Posted by: Seina

Re: Streamflow Observations - 16/02/2011 22:41

GFS forecast has not changed much in 1 1/2 days (now less than 2 days out), in fact the predicted rainfall looks to have increased by another 5-15 mm. Runoff is looking rather significant - approaching 0.7 mm per unit catchment area.

This is beginning to look like a major event!

3-4 days (4 days) to yesterday's thunderstorm (no significiant streamflow runoff), and now 2-3 days till a major rainfall event...very interesting!

This does not look to be a major convective event, it appears to be more a rainband event, hence my keeping an eye on the LWT!
Posted by: Seina

Re: Streamflow Observations - 17/02/2011 13:34

SA Flood Watch has been issued by Bureau...GFS forecast is still not budging...runoff now has (what I consider to be) three major peaks (two over 0.3 mm/area)...0-10 cm soil moisture fraction predicted to jump from 0.16 to 0.3...
Posted by: Seina

Re: Streamflow Observations - 18/02/2011 16:29

Been raining here since roughly 7 am...exceeded 25 mm sometime around 12 noon...

SEVERE WEATHER WARNING for FLASH FLOODING
Posted by: Seina

Re: Streamflow Observations - 18/02/2011 18:03

The river is flowing, pools are linked...exceeded 40 (mm) about 30 mins ago. Moderate almost heavy rain!
Posted by: Seina

Re: Streamflow Observations - 18/02/2011 20:21

54.3 mm 7 am to 7:50 pm.
Posted by: Seina

Re: Streamflow Observations - 19/02/2011 18:00

Written 13th of February ([] added):

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
The temperature is too high (29) the RH too low (~30%), and pressure continues to fall (~999)...and the river has lost another quarter to half a metre...winds are picking up,...and my initial thinking is rain/showers, with a dump not out of the question!

Pressure has risen, 998 from 994, RH: ~90%, temp ~20. 1 mm in the 8 hours to 10:20 am (light showers), 7 mm to 11:30 am (thunderstorm and downpour 3 mm in 20 mins).

Another .5 mm brings the total to 8.5.

[Note 1: Friday 11th February, P: 998 hPa, Tmax/min: 21/18 C].

On another note, the PWATclm variable (atmospheric column precipitable water) on the GFS forecast is on a bit of a rollercoaster ride over the next week or so...in a day’s time [14th] it is forecast to rise from the current ~12.5-13 kg/m^2 to 36 by Tuesday [15th] night. It then falls again to around 18 and a bit kg/m^2 by Thursday night [17th], followed by a rise to a lesser peak of maybe 33-34 kg/m^2, which is a long way out [19th]. Might be a bit wet, will see smile .

Today:

[Note 2: 15th February rainfall: 8.4 mm. P: 998 hPa. Tmax/min: 31/11 C].
[Note 3: 18th February P: 998 hPa. Tmax/min: 19/16 C].

Rainfall total (18th: 57.4 mm) which eclipses last year's (2010's) 55.1 on the 3rd of September. Rainfall was over two times monthly average (~27 mm), in one day.

Onkaparinga Flow, 10/2/2011, 1.55 pm



Onkaparinga Flow, 18/2/2011, 2.30 pm (Downstream)



Onkaparinga Flow, 18/2/2011, 5.28 pm (Downstream)



Onkaparinga Flow and Rain: 18/2/2011, 5.28 pm (Upstream)



Onkaparinga Flow and Rain: 18/2/2011, 6.43 pm (Downstream)

Posted by: Seina

Re: Streamflow Observations - 20/02/2011 19:47

Cannot see anything substantial streamflow-wise (or indicating significant flows) for at least a week...
Posted by: Seina

Re: Streamflow Observations - 20/02/2011 20:12

One thing I have discovered in some paddock areas 50-100 m from the river edge is that at 20-50 cm depth there is a layer of sand in the soil which appears to contain no moisture (only pore spaces - air) - it's that dry. There appears to be a water-logged clay layer situated above the layer of sand (0-20 cm), which contains rather a lot of nutrient material and moisture. Deeper layers are much more difficult to figure out.

To some extent this (0-50 cms) might explain why runoff has been more substantial this summer (so far), and why the soil is more water-logged - the top 0-20 cm may be acting as a semi-permeable layer slowing the infiltration of moisture to lower layers, and for some reason the 20-50 cm sand layer doesn't factor in (in that area); possibly because the moisture either evaporates or takes a rather long time to sink into the soil en route to the river.

Judging from the rain rate on Friday, the threshold infiltration rate was exceeded (or the soil was very water-logged already), otherwise the river wouldn't have risen the approx. half to one metre it did - that is, 0.5-1 m by 5-10 wide.

The level of moisture in the soil is at about the level of the riverbed in the deepest sections, which is also intermingled with bedrock, suggesting a dynamic soil profile, not a simple one.

It is still very green for this time of year, very...judging from GFS forecasts, stream obs and in-field measurements I'd say there's a lot more moisture to come in the months ahead smile .

1.4 mm today from a passing front.
Posted by: Seina

Re: Streamflow Observations - 23/02/2011 16:24

Noticed an ant nest with raised edges today built in a place you wouldn't normally think (on bricks).
Posted by: Seina

Re: Streamflow Observations - 25/02/2011 13:22

Two points worth considering:

14-02-2011 12:09 PM
(A):
Originally Posted By: -Cosmic- (naz)
Supplementary Note:

All these anomalies that seem to be occurring in the observations are threatening to culminate in something…

[I'm talking within a year].

P: still 1013 hPa.

The rain on the 18th could have been just that and

20-02-2011 07:47 PM
(B):
Originally Posted By: -Cosmic- (naz)
Cannot see anything substantial streamflow-wise (or indicating significant flows) for at least a week...

I think we’re talking about a bit more than just a week…
Posted by: Seina

Re: Streamflow Observations - 04/03/2011 13:58

Originally Posted By: -Cosmic- (naz)

20-02-2011 07:47 PM
(B):
Originally Posted By: -Cosmic- (naz)
Cannot see anything substantial streamflow-wise (or indicating significant flows) for at least a week...

I think we’re talking about a bit more than just a week…

I had "months" in mind at the time...but I'm not particularly sure yet...

...atmospheric conditions like those today suggest it might be more than a month or two.

Edit:

To be honest, I wouldn’t be surprised if it didn’t started raining again (substantially) until April.
Posted by: Seina

Re: Streamflow Observations - 06/03/2011 15:07

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Cannot see anything substantial streamflow-wise (or indicating significant flows) for at least a week...

To be honest, I wouldn’t be surprised if it didn’t started raining again (substantially) until April.

Bold Added.
Still not convinced (about 7th-8th)!
Posted by: Seina

Re: Streamflow Observations - 07/03/2011 11:45

On second thoughts...(!?) (looking at obs).
Posted by: Seina

Re: Streamflow Observations - 07/03/2011 12:35

Originally Posted By: -Cosmic- (naz)
On second thoughts...(!?) (looking at obs).

I was looking outside and seeing convection starting...still not much...

Seriously, I'm really quite hesitant about anything significant coming from the system streamflow-wise, I think it will be more hit-and-miss...

This may come down right to the last hour, but I have my doubts!

The forecast runoff according to GFS continues to fall, and so does the forecast rain (now about 25 mm from an initial 70)!

For now I stand by a non-significant event!
Posted by: Seina

Re: Streamflow Observations - 07/03/2011 18:18

The pressure is plummeting - now 993. Temp: 28, RH: 36%.
Posted by: Seina

Re: Streamflow Observations - 08/03/2011 17:17

River flow is becoming significant...and will continue to do so until these rain periods abait.

For people downstream of Woodside, I would say it is a good idea to keep clear of the river edge...there is a lot of water making it's way downstream. This is simply a common sense suggestion on my part.
Posted by: Seina

Re: Streamflow Observations - 08/03/2011 22:46

I wasn’t going to post this, but I will now smile :

18th Feb: 57.4 mm (24 hours). System total 59.8 mm.
18 days later: 57.9 mm (19.5 hours) (system-to-date 59.4 mm) (and starting again right now, 9:40 pm).

Written 7/3/2011

I have been a bit opposed to the idea there might be a bit of rain on the way for this month (while we need rain, perhaps another major system like this within less than a month is a bit much),

So hesitantly…despite this:

Written 2/3/2011
From Page 17:

Originally Posted By: -Cosmic- (naz)
Re: Last Special Note (31-1-11)

There's forecast (BoM, ACCESS) a frontal system passing in the Southern Ocean, heading north. It looks like this will interact with remnant moisture from the passing Severe TC Yasi to form new lows between SA and VIC, and a potentially a series of lows across the top end associated with the Monsoon Trough. The result is potentially heavy, consistent rainfall for a period of perhaps a day or two on the leading edge of the front/NW cloudband interaction (40-50 mm).

Temperature will be affected significantly for this period (25 C or lower), the pressure will rise in the wake of the passing frontal system, and expect the (specific) humidity to plummet sometime around the 7th-8th, followed by a sharp increase towards the 9th.

Rainfall is likely to be heaviest round 7th-8th, at a guess.

Notably the specific humidity is now forecast to do the opposite (fall towards tomorrow, the 9th).

The first day of autumn has passed, and it was cool (17).

We have what looks like another spike in the PWATclm variable predicted (GFS) for 7th-8th…

…going from 10 kg/m2 to 28.

[Update 6/2/2011: 10 k/gm2 to 50 kg/m2 by the 8th].

1000-500 mb Thickness gradually rising to about 5760 m (indicating the temperature is expected to rise today and tomorrow).

[Update 6/2/2011: slightly less: 5750 m].

Temp low 30s.

[Update 6/2/2011: Maybe 30].

Specific humidity up to ~0.0095 kg/kg (atm it’s less than 0.0085).

[Update 6/2/2011: ~0.006 to 0.0145].

Long-term spectral model (MRF) has PWATclm peaking at almost 40 on the 13th and 15th (in between is a sharp fall).

Long-term, the mean sea-level pressure is erratic – falling gradually from 1018 to 1008 by the 13th, jumping to 1013 the next day, back to 1003 the next, and about 1020 the next (???).

Total atmospheric column cloud cover jump from about 30 to 90-95% three times in 6 days (9th to 16th) – suggests frontal activity to me.

The precipitation rate for each front is 2, 4 and about 13 mm respectively…

I can’t recall seeing the mean sea-level pressure jump from 1003 to 1020 like that.

[For anyone not sure, PWATclm means an “X”-mm depth of water on the ground if you condense all the water in the atmosphere above you. So 10 kg/m2 = 10 mm, etc.]

Written 4 or 5/3/2011:

GFS apparently has 70 mm predicted starting 7th into 8th. Streamflow is meant to be peaking four times, twice above 0.55 kg/m2 (half a millimetre in depth over the catchment).

[Update 6/2/2011: one major 0.3 kg/m2 peak].

The most significant indicator for streamflow is the 0-10 cm volumetric soil moisture fraction, forecast to rise from roughly 0.09 to about 0.3 in about a day.

[Update 6/3/2011: 0.1 to 0.28, so a bit less].

I’m not holding my breath or getting carried away on this…but:

The forecast change in the 0-10 cm volumetric soil moisture fraction is greater than both that for December and the last major rainfall event!

Now: 7/3/2011

I’m still not budging much on this coming rain…don’t think we’ll get 70 mm. Maybe 5-10, even though it’s only 0.5-1 days out.

Current temperature 29 and pressure 1008.
Posted by: Seina

Re: Streamflow Observations - 09/03/2011 13:06

Video of moderate flow along the Onkaparinga, yesterday

61.4 mm system total, to-date.
Posted by: Seina

Re: Streamflow Observations - 09/03/2011 13:51

Posted by: Seina

Re: Streamflow Observations - 14/03/2011 15:08

What are the ants waiting for? They've built their (large) nests (10th), dragonfly numbers are up (12th), streamflow increased noticeably on the 12th and is now down (14th). Pressure is a solid 1010 hPa, temp 27, RH 38%, precip yesterday 0.2 mm...

Interesting!
Posted by: Seina

Re: Streamflow Observations - 15/03/2011 17:02

Not sure what's going on with the weather/rain in the next two weeks, but I think wild-life and local river might have something frickin' huge in mind. I don't know what it is, the (river) conditions and weather are defying the models, and something is missing from the equation. Streamflow has already increased without rainfall some 3 days ago, the large (ant) tests are still around. Go figure!? confused.

One point of interest: the river level has barely changed since the 10th.
Posted by: Seina

Re: Streamflow Observations - 18/03/2011 12:48

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)

20-02-2011 07:47 PM
(B):
Originally Posted By: -Cosmic- (naz)
Cannot see anything substantial streamflow-wise (or indicating significant flows) for at least a week...

I think we’re talking about a bit more than just a week…

I had "months" in mind at the time...but I'm not particularly sure yet...

...atmospheric conditions like those today suggest it might be more than a month or two.

Edit:

To be honest, I wouldn’t be surprised if it didn’t started raining again (substantially) until April.

Nup, I'm going to stand by my original thoughts...until demonstrated otherwise (for March).
Posted by: Seina

Re: Streamflow Observations - 19/03/2011 14:33

As demonstrated by observations, the forecast (morning) total atmospheric column cloud-cover of 0% for today is accurate...
Posted by: Seina

Re: Streamflow Observations - 20/03/2011 10:31

GFS has upgraded both rainfall and streamflow for today by 15 mm and 0.2 kg/m2 respectively...rrr eek .
Posted by: Seina

Re: Streamflow Observations - 20/03/2011 12:50

P: 998. Rh: 77%, T: 19 C.

GFS Frcst: Sfc. P: 992. Rh: 94-95%, T: 18-19.
Posted by: Seina

Re: Streamflow Observations - 21/03/2011 12:06

12.5 mm of steady rain, no significant runoff!

There is a thick morning fog which has not lifted yet. Light drizzle.
Posted by: Seina

Re: Streamflow Observations - 28/03/2011 22:02

After 46.7 mm, 20th-26th, observations confirm streamflow estimates - no signficant change in runoff!

I might be sticking to in-field obs more in the future.
Posted by: Seina

Re: Streamflow Observations - 31/03/2011 10:47

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Cannot see anything substantial streamflow-wise (or indicating significant flows) for at least a week...

I think we’re talking about a bit more than just a week…

Preliminary: Give it 24 hours.
Posted by: Seina

Re: Streamflow Observations - 31/03/2011 11:18

The pressure is 1021…! If that’s not saying something I don’t know what is!
Posted by: merrilllynch

Re: Streamflow Observations - 31/03/2011 11:46

Cool, I enjoyed reading and learn some new things here....Goodluck....
Posted by: Seina

Re: Streamflow Observations - 06/04/2011 21:06

On the 1st of April, conditions were conducive to rainfall with a trace recorded. The date of the 1st of April for the next significant flow event was not set in stone because during the last major rains, 46.7 mm completely or almost completely infiltrated into the soil (over 7 days), and had little or no affect on streamflow. The rain rate was insufficient for runoff because it did not exceed the infiltration threshold. This is despite some 61.5 mm falling over a 4-day period from the 7th to the 10th of March, most of which fell on the 8th with a much greater precipitation rate.

When “months” was implied for the period to the next likely significant streamflow that is what I meant…not just one. It’s now been 28 days since the last event.

On another note, apparently the equation I have been using for estimating streamflow cannot be reversed analytically to estimate rainfall. The integral of the equation is a complex system of the logarithmic function and the incomplete gamma function over the range (0, -x).

The analytical form of the equation which gives the streamflow estimates is an exponential integral function. There is analytical derivative for this function, but it is extremely complex.

[...One last note, a regression analysis of NOAA data over a greater than 50-year period potentially indicates rainfall correlated highly enough with functions of evaporation, surface vapour pressure and latent heat flux that concurrent estimates of monthly rainfall can be made.]
Posted by: Seina

Re: Streamflow Observations - 13/04/2011 15:35

A discernible, post-rainfall increase in streamflow has been observed at several locations along the Onkaparinga today smile.

This increase in streamflow appears to be unrelated to the recent rainfall event ending yesterday for which we received 11.5 mm over 5 days.
Posted by: Seina

Re: Streamflow Observations - 13/04/2011 21:57

1008 hPa, 77% Humidity, 12 C.

Has started raining...
Posted by: Seina

Re: Streamflow Observations - 17/04/2011 12:13

Originally Posted By: -Cosmic- (naz)
1008 hPa, 77% Humidity, 12 C.

Has started raining...

1.9 mm total over 2 days...negiligible change in flow; remains steady.

The Global Spectral Model Run (MRF) from NOAA shows a possibly major rainfall event towards the end of the month (forecast 00Z15apr2011 to 12Z30apr2011 PRATE 1000 and PRMSL 1000). This may or may not have been an anomlay (the next run does not appear to indicate the same rainfall totals, ~40-50 mm).

A moderate flow is expected from this rain at this stage (~1.6 units). September 3rd 2010 flow was over 20 units. The pressure (MRF MSLP) is expected to drop markedly to 1006 from around 1021.

Flow has not been significant or even moderate since about 0.47 units was estimated on the 23rd of March this year.
Posted by: kimballthurlow

Re: Streamflow Observations - 17/04/2011 16:00

Hi Cosmic-naz,
I understand the BOM responsibility (and your recent posts seem to amplify that) for forecasting and warnings on an Australia-wide and regional basis. Have we become a sufficiently large and sophisticated community where a specialist division of the BOM could be set up to research, understand and monitor the more local ramifications of intense rainfall and other weather events of significance in real-time? I am particularly interested in the usefulness or otherwise of the typical engineering calculation for volume/speed determined from intensity. For example, you talk about dry under-soil contributing to a different rate of run-off. It appears to me that such studies need to occur on a national basis with professional integrity and government support. regards, Kimball
Posted by: Seina

Re: Streamflow Observations - 17/04/2011 21:55

Originally Posted By: kimballthurlow
Hi Cosmic-naz,
I understand the BOM responsibility (and your recent posts seem to amplify that) for forecasting and warnings on an Australia-wide and regional basis. Have we become a sufficiently large and sophisticated community where a specialist division of the BOM could be set up to research, understand and monitor the more local ramifications of intense rainfall and other weather events of significance in real-time? I am particularly interested in the usefulness or otherwise of the typical engineering calculation for volume/speed determined from intensity. For example, you talk about dry under-soil contributing to a different rate of run-off. It appears to me that such studies need to occur on a national basis with professional integrity and government support. regards, Kimball

Firstly, thanks for the your interest smile .

This is a bit of a long-winded explanation…so bare with me smile

I believe we have the resources to begin the process of forming such divisions associated with specialist monitoring, however the science (and in the case of the basis of this thread, streamflow monitoring) is still very much, regionally, in its infancy. There has been a particular major focus recently on understanding the basis of primary contributors to Adelaide Hills catchments (e.g. groundwater in the Willunga Basin south of Adelaide), and more broadly other larger catchments such as those of the Murray-Darling. There are many variables involved in an accurate understanding of groundwater-surface-water related system, suffice to say that there is now the National Centre for Groundwater Research and Training (NCGRT) established at Flinders University.

While groundwater is very important in contributing to the likelihood of significant surface-water events, and likely conditions conducive to major rainfall events, I acknowledge the issue to more how funding is spent and prioritised. Much of it, I believe, goes to water resource management, wherein modelling is conducted based on in-field observations, or quality-controlled datasets. The issue then becomes one of environmental change…which, to say the least, can be profound, both agriculturally and horticultural (I have noticed changes in rainfall even locally within the Central Adelaide Hills region with increasing population and vineyards becoming established).

Since vegetation have been planted along many catchments in the Hills, runoff has become more manageable…however it is and was the initial clearance of vegetation and reduction in available native habitat – environmental change during and after settlement – which may have likely caused major degradation; this is well documented:

“Assessing the impacts of dryland salinity on South Australia’s water resources”
CSIRO Land and Water, Technical Report, 9/00, Jolly et al. 2000.

Having done some research on Catchments in the Hills…I believe that on occasion environmental changes may not be sufficiently account for, with the likely causes of these being unknown.

My main concerning is consistency, even if what is being monitored is not accurately calibrated, consistent records (using the same process) can be kept at a bare minimum. It makes it far more manageable and straight forward to correct if this done. However, there are some environmental changes which are the focus of our research, so to say regional (or national) change is an “issue” is quite a relative notion.

Hope that goes some way towards shedding light on these things for you smile .
Posted by: kimballthurlow

Re: Streamflow Observations - 18/04/2011 06:24

HI Cosmic-naz,

Thanks for that insight.

I have a particular interest in that sort of thing, as it relates to torrents despatched recently in SE Qld., with subsequent loss of life.

Anyway, there is a Commission of Enquiry here in Queensland, no doubt there will be some professional assessment of what can be done in the future with regard to understanding rainfall input and subsequent stream flows. A useful warning system may result.

regards
Kimball
Posted by: Seina

Re: Streamflow Observations - 21/04/2011 12:09

Originally Posted By: -Cosmic- (naz)
The Global Spectral Model Run (MRF) from NOAA shows a possibly major rainfall event towards the end of the month (forecast 00Z15apr2011 to 12Z30apr2011 PRATE 1000 and PRMSL 1000). This may or may not have been an anomlay (the next run does not appear to indicate the same rainfall totals, ~40-50 mm).

A moderate flow is expected from this rain at this stage (~1.6 units). September 3rd 2010 flow was over 20 units. The pressure (MRF MSLP) is expected to drop markedly to 1006 from around 1021.

It seems there may be an increasing likelihood of significant rainfall on or around the 29th of April…
Posted by: Seina

Re: Streamflow Observations - 21/04/2011 12:25

It's not 12 pm CST (Central Standard Time) yet...but I am suspicious there is a risk of thundery showers/rain this afternoon.

...particularly for the Lower Southeast.
Posted by: Seina

Re: Streamflow Observations - 24/04/2011 14:23

22/04/2011:

2.4 mm overnight. Currently 21 C (12:10 pm) with a light SSWerly. Mediocre Cumulus about. Pressure: 1011 hPa.

23/04/2011:

The peak in rainfall (MRF) circa beginning of next month is still there. Pressure: 1018 hPa (7 pm).

24/04/2011:

The peak in rainfall is now visible in the 7-day run (GFS)…in fact two peaks around the 29th. The first peak reaches almost 6 mm, the second about 9 mm. The peaks are the only ones visible on the graph. The pressure is expected to take a nose dive around the 28th, dropping about 5 hPa…the streamflow (runoff) increases by about 6-fold (to a moderate flow)…soil moisture (top layer) jumps abruptly, by about 4% (if I’ve interpreted that accurately).

Most impressively of all the precipitable water (PWAT) climbs gradually (from today) to almost 28 kg/m2, before dropping sharply on the 29th to reach 12 kg/m2 by the 30th.

All the above (notes 23rd-24th) seems to be pointing towards severe weather in a short space of time (maybe a day or two).
Posted by: Seina

Re: Streamflow Observations - 24/04/2011 14:29

Can anyone correct me on this, was I seeing things:

The temperature was only 16 C yesterday (1 C overnight to today)...I thought I saw sleet falling yesterday (very overcast, still)!
Posted by: Seina

Re: Streamflow Observations - 27/04/2011 13:20

Indications are that there is significant weather on the way, starting the 29th.
Posted by: Seina

Re: Streamflow Observations - 27/04/2011 18:40

Rainfall: expecting several peaks including (one or more) 15-20 mm.

Temperature: average (2-metre) below 20 C starting 30th, below 16-18 C thereafter.

0-10 cm soil moisture: jump from 0.11 to 0.18, maintained (i.e. not temporary).

Precipitable water: likely to be around 14 kg/m2 tomorrow, then jumps to 28 kg/m2 by 30th, maintained until the 2nd.

Streamflow (runoff): a moderate peak is expected on or around the 30th of April.

Today’s max temp: 29!
Yesterday max temp: 28!

Forecast temp 4th May: around 16!

Pressure: change is not as noticeable…gradually fall then gradual rise, partially consistent with a system from the west, more so a system from the west combined with a pre-frontal trough and Northwest Cloud band formation.

I suspect there may be an upper-level trough involved as I’m talking (above) about surface or near-surface pressure, not the upper levels.

One last thing to note: on the GFS ACCESSG + 144 HRS Mon 2nd May 2011, the 5400 Thickness Line is clearly over Adelaide.
Posted by: Max Record

Re: Streamflow Observations - 27/04/2011 19:42

Good call on your post from the 21st! smile Not that we don't exactly know how much there will be from then on; it is at least precipitation. And also, don't think you arouse much interest in this thread - I regularly read this. I just don't respond because I don't want to sound dumb. blush wink
Posted by: Seina

Re: Streamflow Observations - 27/04/2011 20:42

Originally Posted By: Max Record
It is at least precipitation.

Yes...looking forward to it smile !

Originally Posted By: Max Record
And also, don't think you arouse much interest in this thread - I regularly read this. I just don't respond because I don't want to sound dumb. blush wink

I'm ok with not much interest to an extent...I simply provide information and some possibilities (or probabilities) based on that information.

Also, I have a thing that if no one looks into this stuff, how are we going to have a better understanding of what goes on in the future.

If you weren’t there to plot it out, how can you claim to know what went on…it also helps to have a computer model or two nearby wink smile .

Lastly, there is no such thing as a dumb question, only the one that everyone wants to ask but no one will lol smile .
Posted by: Seina

Re: Streamflow Observations - 30/04/2011 15:31

There is a trough situated overhead, extending all the back to northwest WA, and down past TAS. All that is (seems) needed is an increase in the dewpoint and for a “kink” to develop in the trough (to the north), and tomorrow’s forecast of 10-20 mm is looking increasing likely.

You almost have to look all the way back to the Western Indonesian Archipelago to see what’s going on.
Posted by: Seina

Re: Streamflow Observations - 02/05/2011 14:39

The GFS (AVN) was accurate to within less than a millimetre (6.5 mm to 6.7 mm actual), to within the last 3 hours of the forecast for yesterday.

No significant/moderate runoff.
Posted by: Seina

Re: Streamflow Observations - 04/05/2011 20:20

Streamflow has been increasing gradually, audibly over the last 3 days...this is very unlikely to be a consequence of 9.9 mm falling over a period 29/4/11 to 2/5/11...it's more likely a consequence of sub-surface (groundwater) flow, the pressure having increased from 1009 hPa on the 2/5/11 to 1018 hPa today.
Posted by: Seina

Re: Streamflow Observations - 05/05/2011 10:08

Originally Posted By: -Cosmic- (naz)
Streamflow has been increasing gradually, audibly over the last 3 days...this is very unlikely to be a consequence of 9.9 mm falling over a period 29/4/11 to 2/5/11...it's more likely a consequence of sub-surface (groundwater) flow, the pressure having increased from 1009 hPa on the 2/5/11 to 1018 hPa today.

Now higher than 1020...

Also:

http://www.epa.sa.gov.au/xstd_files/Water/Brochure/fact1.pdf
http://www.epa.sa.gov.au/xstd_files/Water/Report/mtlofty.pdf
Posted by: Seina

Re: Streamflow Observations - 06/05/2011 12:32

Unfortunately this is a little in retrospect, so it isn't really a prediction:

What looks like a cut-off low that has formed in the Bight off a frontal system...these can be the types lows that generate much of the "breaking winter rains" across Southern Australia, and in particular the Southeast.
Posted by: Seina

Re: Streamflow Observations - 06/05/2011 12:49

It might be worth watching this low for a while (with the activity off the NW coast of WA) to see what happens smile .
Posted by: Seina

Re: Streamflow Observations - 07/05/2011 12:30

There seem to be warning signs from this system...for tomorrow.
Posted by: S .O.

Re: Streamflow Observations - 07/05/2011 21:29

Yeah , Today In Vicco , it just looked Ominous . Alot cooler than SA too . Note Hobarts max Tomorrow , and probably even cooler Wed/Thurs .

As of yet the Action off NW hasn't really fed in ? Maybe we'll be in for a Surprise ....
Posted by: Seina

Re: Streamflow Observations - 07/05/2011 22:35

To clarify:
Originally Posted By: -Cosmic- (naz)
There seem to be warning signs [of rainfall] from this system...for tomorrow.

We've had rain, fall...today smile!

...just haven't checked yet.
Posted by: Seina

Re: Streamflow Observations - 07/05/2011 22:45

Originally Posted By: Southern Oracle
Maybe we'll be in for a Surprise ....

That would be nice.
Posted by: Seina

Re: Streamflow Observations - 08/05/2011 19:19

Originally Posted By: -Cosmic- (naz)
To clarify:
Originally Posted By: -Cosmic- (naz)
There seem to be warning signs [of rainfall] from this system...for tomorrow.

We've had rain, fall...today smile!

...just haven't checked yet.

0.1 mm yesterday, 0.3 mm today..so far smile!
Posted by: S .O.

Re: Streamflow Observations - 08/05/2011 21:29

Yes , unfortunately from what I'm seeing of it , only east of a line from Warnambool (VIC) to Parkes (NSW) , will see any interaction of Southern Cold air with Moisture interactions .
Posted by: Seina

Re: Streamflow Observations - 08/05/2011 22:20

Originally Posted By: Southern Oracle
Yes , unfortunately from what I'm seeing of it , only east of a line from Warnambool (VIC) to Parkes (NSW) , will see any interaction of Southern Cold air with Moisture interactions .

Agreed, this isn't the system I thought it was (35-40 mm).

Edit:

It doesn't help explain the middle-level displays of altocumulus (very apparent) spanning the northwest quadrant about midday on the 6th and earlier in the, day directly overhead.
Posted by: S .O.

Re: Streamflow Observations - 08/05/2011 23:02

I would have thought it hinted at being the system to actually draw up this Very Cold Air, that's ( uniquely ) slid into a S/N trajectory as I Type , over Vic . As for you getting Rain ( Real Falls ) , that will come Midweek . Very hard to predict when , but the complexity of the Fronts ' ( yes Plural ) and the ability for a Cut off Low to spin up in Bass straight . It's matter of Only a few hundred KM's that will see it Seed either West of Tassie , on the Border of SO/ Bass or east actually on the Tasman/Bass Junction .

Obviously if we see it start to favour the west side , then the Adelaide Hills and as far Nth as Arkaroola are a good chance of decent falls (10+mm's).One model I've seen supports this .
As i mentioned the timing is almost Impossible , but the West/East aspect will be reasonably easier with a watch of whether the Trough in
QLD/N-NSW spins up and hogs alot of the High level Moisture or it takes awhile to organise and we see it drift a little further sth and enabling a further South Tasman Interaction when further fronts arrive as the week progresses .
A retrograde/ sw movement will help , one to monitor .
And if it nears atleast Sth of Ulladulla and closer to Eden we may see the interaction bridge From one side of Bass Straight to the other . Hence a much further west precipitous area .
Posted by: Seina

Re: Streamflow Observations - 09/05/2011 13:03

Judging by the GFS 18Z08may2011 to 06Z16may2011 run, streamflow is predicted to increase 7-8 fold by the 11th...with maybe 30 mm on that day. Looks like it'll be pretty cold. Was 13 C late this morning if that wasn't cold enough...with another trickle (0.3 mm).
Posted by: Seina

Re: Streamflow Observations - 09/05/2011 23:16

0 Degrees Celsius @ 10:40 pm CST.
Posted by: S .O.

Re: Streamflow Observations - 10/05/2011 00:29

Out of interest , when was the last time you got snow in mid/late Autumn in the Flinders ranges / Adelaide Hills / Fleurieu . ?
Posted by: Seina

Re: Streamflow Observations - 10/05/2011 17:40

Originally Posted By: Southern Oracle
Out of interest , when was the last time you got snow in mid/late Autumn in the Flinders ranges / Adelaide Hills / Fleurieu . ?

You're talking 1999-2000. In 1996 there was definitely snow.

To be honest minuses are not that uncommon up here...last night's low was the 8th at or below 2 C since Saturday the 23rd, last month. Today top was 20 C.

Edit:

The day I witness another flood like that of 1995 and 1996,...that will be interest given how much the landscape has changed since then!
Posted by: Seina

Re: Streamflow Observations - 10/05/2011 17:51

Most of the photographs/videos presented here don't give a full appreciation of the scale of the floods of the mid-to-late 1990s.
Posted by: Seina

Re: Streamflow Observations - 10/05/2011 18:29

Light-to-moderate rain here smile. Drizzle-to-light since about 5 (this arvo).
Posted by: S .O.

Re: Streamflow Observations - 10/05/2011 18:37

Photo's videos above ????

And current Temps with precip ?
Posted by: Seina

Re: Streamflow Observations - 10/05/2011 22:24

Originally Posted By: -Cosmic- (naz)
Most of the photographs/videos presented here [in this thread] don't give a full appreciation of the scale of the floods of the mid-to-late 1990s.


Originally Posted By: Southern Oracle
And current Temps with precip?

20 C/0 C (today) , 2.1 mm (today), 88% humidity (6:30 pm).
70% humidity (~7:30 pm), 82% (now). 9 C (now).
Posted by: Seina

Re: Streamflow Observations - 11/05/2011 11:07

If we're after significant runoff...I don't think intermittent mostly light showers are going to be sufficient.

I still have that "it'll be months before we see signficant runoff again" ringing in my ears. That was back in March.
Posted by: Seina

Re: Streamflow Observations - 12/05/2011 13:14

Longer-term we're actually exceeding our 1990-2005 annual average total (to date) by about 70 mm, March this year being an excessively wet month.
Posted by: Seina

Re: Streamflow Observations - 13/05/2011 13:51

I can use rainfall variables and proxies to model monthly streamflow (mm/day) relatively well (concurrently), and daily flows to a lesser extent...

I am also aware of lags between rainfall in the region and climate phenomena, however the correlations for the lags are currently not significant enough to generate longer-term forecasts.

More research to be done smile .
Posted by: Seina

Re: Streamflow Observations - 15/05/2011 14:33

The prssure increased 9 hPa from Friday to yesterday, streamflow noticeably increased last night at about 6pm, the pressure up to ~1028 (another 6 hPa higher), and is still hovering around 1027 hPa. I think this is quite high for the area.

Just looking at the satellite map animation (BoM), I might be inclined to think the next few months (Winter) is going to particularly wet, with a major rain event later on this month (~20th-22nd)...will see smile .
Posted by: Seina

Re: Streamflow Observations - 19/05/2011 13:08

Originally Posted By: -Cosmic- (naz)
Just looking at the satellite map animation (BoM), I might be inclined to think the next few months (Winter) is going to particularly wet, with a major rain event later on this month (~20th-22nd)...will see smile .

I think major is quite an adequate description at this point.
Posted by: Max Record

Re: Streamflow Observations - 19/05/2011 17:12

Probably 50mm for you, but just 20mm for me being a plains dweller. wink
Posted by: Seina

Re: Streamflow Observations - 19/05/2011 21:05

Originally Posted By: Max Record
Probably 50mm for you, but just 20mm for me being a plains dweller. wink

I was actually thinking more than that...but it could still be a red herring if the in-field obs are slightly off. The rainfall peak is definitely there in any case smile .

I'm seriously expecting the pressure to plummet come Saturday Night-Sunday Morning.

23 degrees after and overnight low of 6 today.
-2 being the lowest to date, with a frost.
Posted by: Seina

Re: Streamflow Observations - 19/05/2011 21:17

We might get a very sharp and abrupt change in streamflow.
Posted by: Max Record

Re: Streamflow Observations - 19/05/2011 21:25

Although I'm not extremely well versed in the weather dynamics, the isobars certainly indicate a wild Sunday, wind wise! Bit of swell to be had on the coasts, I'd imagine.
Posted by: Seina

Re: Streamflow Observations - 20/05/2011 12:04

The pressure is beginning to fall a bit now...down to ~1017.

I think it might be fairly windy on Sunday, yes.

Very interesting, could also be stormy if the forecast holds.
Posted by: Seina

Re: Streamflow Observations - 21/05/2011 10:45

Two words: wet and cold! It might actually be three if you put very in front of wet.
Posted by: Seina

Re: Streamflow Observations - 21/05/2011 21:47

It (GFS) is a model which is a representation of what is likely to happen in reality...but it's still interesting that it's upgraded the overnight total to 10-20 mm, with an very interesting peak of 60-70 mm the follow day.

I guess understandably the runoff has also upgraded to one might sharp peak over that period.
Posted by: Seina

Re: Streamflow Observations - 21/05/2011 21:59

Originally Posted By: -Cosmic- (naz)
The pressure is beginning to fall a bit now...down to ~1017.

Now 1004.
Posted by: Seina

Re: Streamflow Observations - 22/05/2011 13:16

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
The pressure is beginning to fall a bit now...down to ~1017.

Now 1004.

Now 996. Wet and Windy.
Posted by: Seina

Re: Streamflow Observations - 22/05/2011 16:31

20 mm in 16 hours to 4 pm...and getting heavier!
Posted by: Seina

Re: Streamflow Observations - 22/05/2011 16:50

Rain rate as at 4:15 pm: 12 mm/hr.
Posted by: Seina

Re: Streamflow Observations - 23/05/2011 21:47

Barometric Pressure ~11.20 am, 15/5/2011



Barometric Pressure ~4.15 pm, 22/5/2011



Rainfall and Surface Pressure, 1/1/2011 to 6 pm 23/5/2011.



Rainfall and Estimated Streamflow (Index), 1/1/2011to 6 pm 23/5/2011.



35.6 mm, 12 pm 21st to 6 pm today. Slight change in streamflow (0.25 – 0.5 metres):

http://www.bom.gov.au/fwo/IDS60247/IDS60247.523714.plt.shtml
Posted by: Seina

Re: Streamflow Observations - 27/05/2011 12:41

51.9 mm 21st-26th May...rain has not been heavy enough for a significant change in runoff.

Drizzle on and off today.

Edit:

There is the possibility streamflow increased when observations were not being taken, on the morning of the 24th.
Posted by: Max Record

Re: Streamflow Observations - 28/05/2011 00:15

Originally Posted By: Max Record
Probably 50mm for you, but just 20mm for me being a plains dweller. wink


51.9mm for you and 29.2mm for me. smile
Posted by: Seina

Re: Streamflow Observations - 30/05/2011 15:55

The pressure is continuing to climb gradually, now past 1020…

This is a follow-on from a recent comment in the “Developing and Understanding of the Earth Climate System” thread. In that comment I said something to the effect that the climate in South Australian Mediterranean Regions in changing to become more humid sub-tropical. I still believe it is. This belief is not just based on my understanding (to date) of how climate works, but also on simply observing environmental changes. If I was to pin-point the year when I first started to notice these changes, I would say 2004, for a myriad of reasons. The consequences for streamflow as a result of these changes are, I believe, quite significant.

While a cause for many of the changes cannot be pin-pointed, it is abundantly clear these cannot be solely attributed to the IOD or ENSO phenomena…by that I mean the SAM also warrants a mention.

I draw your attention to this (which was not just a blind suggestion):

This is an existential sub-note.

Re: Streamflow Observations [Re: -Cosmic- (naz)] #919790 - 02-01-2011 12:28 PM

Quote:
Sub-Note:

It is understood that what happens in the Southern Ocean many, many months ago affects the climate dynamics locally (particularly rainfall) in South Australia through changes in the SST and pressure, and potentially to a reduced extent areas of the Northern Territory, Central and Western WA, parts of Queensland and South-western Victoria. This is quite apart from the ENSO phenomenon which is based in the Pacific, although the two may overlap/interact to some extent.

Of significance to this ENSO-Southern Ocean relation is likely the Northwest Cloud band, extending from the North-western-most corner of South Australia to Southern Victoria. This feature has become more prominent in recent years, bringing with it much moisture from the tropics and sub-tropics. During summer, this moisture is known to contribute to flooding and flash-flooding in numerous South Australian Regions. The Northwest Cloud band is also associated with the passage of various frontal systems across Southern Australia, and is also noticeable in their absence when high-pressure cells are present in the Bight.

The Southern Ocean SST-pressure phenomena can be associated the rainfall in this region through the development of North-westerly winds and large changes in regional pressure. However, unlike atmospheric events which can take days to develop, oceanic phenomena may take several years, which potentially gives a huge lead-time to forecasting rainfall in South Australia and various other regions.

I would urge more research be conducted into these aspects of climate and their impacts on microclimatic conditions, as there are potentially significant implications for water management and natural disaster mitigation both within and beyond South Australia.
Posted by: Seina

Re: Streamflow Observations - 31/05/2011 19:20

Another frost with 0 degrees last night...quite still, pressure 1020 @ ~6:50 pm. Streamflow is fairly audible at this time.
Posted by: Seina

Re: Streamflow Observations - 03/06/2011 12:20

The way the temperature and pressure have been behaving recently suggests there is severe weather on the way. Currently 18 degrees.
Posted by: Seina

Re: Streamflow Observations - 10/06/2011 10:06

By around the 14th the 1000-500 Thickness could start rising substantially.
Posted by: Seina

Re: Streamflow Observations - 10/06/2011 10:35

Time Lapse, 8th June 2011…A cold winter’s day (afternoon)
Posted by: Seina

Re: Streamflow Observations - 13/06/2011 20:56

Originally Posted By: -Cosmic- (naz)
The way the temperature and pressure have been behaving recently suggests there is severe weather on the way. Currently 18 degrees.

Highest maximum temperature in the last week: 18 degrees.

I can only really agree with our local forecast atm!

...well, mostly.
Posted by: Seina

Re: Streamflow Observations - 13/06/2011 21:35

Originally Posted By: -Cosmic- (naz)
Originally Posted By: Southern Oracle
Out of interest , when was the last time you got snow in mid/late Autumn in the Flinders ranges / Adelaide Hills / Fleurieu . ?

You're talking 1999-2000. In 1996 there was definitely snow.

To be honest minuses are not that uncommon up here...last night's low was the 8th at or below 2 C since Saturday the 23rd, last month. Today top was 20 C.

Edit:

The day I witness another flood like that of 1995 and 1996,...that will be interest given how much the landscape has changed since then!

Any more thoughts on that?
Posted by: Seina

Re: Streamflow Observations - 16/06/2011 21:12

Pressure has dropped 16-18 hPa in 3 days.
Posted by: Seina

Re: Streamflow Observations - 17/06/2011 13:19

With each passing day the probability of a significant rainfall-streamflow event over the period 20th-21st increases smile .

Let's not forget the possibility of snow/hail that comes with it grin .
Posted by: Markus

Re: Streamflow Observations - 17/06/2011 13:52

defiently looking great for rainfall! lets hope it pans out...oh and pushes more north to give us all some descent rain grin
Posted by: Seina

Re: Streamflow Observations - 17/06/2011 22:26

Originally Posted By: -Cosmic- (naz)
With each passing day the probability of a significant rainfall-streamflow event over the period 20th-21st increases smile .

Let's not forget the possibility of snow/hail that comes with it grin .

Gee, if the forecast holds...this might not just be significant.

Originally Posted By: -Cosmic- (naz)
By around the 14th the 1000-500 Thickness could start rising substantially.

Slightly...followed by a plung on the 20th, or thereabouts.
Posted by: Seina

Re: Streamflow Observations - 17/06/2011 22:43

And before I forget, streamflow was observed to increase today without substantial falls.
Posted by: Seina

Re: Streamflow Observations - 19/06/2011 13:14

Looking good smile (for significant).
Posted by: Seina

Re: Streamflow Observations - 20/06/2011 09:31

...forecast rainfall has increased substantially...hmmm.
Posted by: Seina

Re: Streamflow Observations - 20/06/2011 15:42

Just for interests sake, the change in flow from now till the peak is slightly more 250 times. In other words >250 x current flow = peak flow.

I leave that open to interpretation.
Posted by: Seina

Re: Streamflow Observations - 25/06/2011 16:06

Peak flow, (6.52 am, 21st).



Streamflow Before (20th, 11.45 am):



Streamflow After (22nd, 1.40 pm):



Ants have been building their nests.

1.35 pm, 17th:



Same nest, 2.35 pm, 23rd.

Posted by: Seina

Re: Streamflow Observations - 26/06/2011 21:24

Ok, I'm not sure whether the models are going to pick up on this, but I'm going to make comment on it anyway smile .

The 1000-500 mb Thickness is predicted to take a dive towards tomorrow morning. The specific humidity is diving around the same time, but much sharper, seemingly briefly.

The effects on the ground might notice able as a change in atmospheric stability...and humidity in general.
Posted by: ROM

Re: Streamflow Observations - 26/06/2011 22:14

The ECMWF maps have a good looking slow moving rainband [ 6 hr precip ] coming into Adelaide at about 4am Saturday 2nd july and clearing through by evening.
They're not forecasting a big dump at this stage though.

Interesting ant mound pic Cosmic.
I always took time to sit down and watch ants go about their fascinating business.
Those ant nests look like one of our mostly night working species. Don't know for sure of course from here.
If they are you rarely see them during the day and the colony is usually found in a cluster of quite widely spaced holes over perhaps 10 or 20 metres across the colony with possibly only a half dozen holes / mounds and couple of dozen large ants in each hole.
That species are a bit hard to get enthusiastic about rain but when they decide that there is going to be some copious quantities of rain they really settle down and throw up some large very steep sided mounds that can get 5 or 6 inches high around the holes.
That's rare but when they do get the boat out!

Each ant species has a different type of deposit, shape of mound and surprisingly, different soil shadings as each species apparently goes to different depths and therefore different soil profiles with their nests.
I've counted the nests of eight different species from ones you could barely see to big guys you wouldn't want to tangle with in just one square metre out side of our farm house gate. And everybody just got on and minded her own business with no visible conflict anywhere.
Posted by: Seina

Re: Streamflow Observations - 27/06/2011 22:08

Originally Posted By: ROM
The ECMWF maps have a good looking slow moving rainband [ 6 hr precip ] coming into Adelaide at about 4am Saturday 2nd july and clearing through by evening. They're not forecasting a big dump at this stage though.

We’ll see what happens over the next few days…interesting stuff on the ants smile .
Posted by: Seina

Re: Streamflow Observations - 28/06/2011 20:39

Streamflow increased audibly on the 26th, at around 9:30 pm.

Today's stats:

Max/Min 18/0, RH (Max/Min) 90/26, Pressure @ ~6.55 am: 1028 hPa.
Posted by: Seina

Re: Streamflow Observations - 30/06/2011 14:58

The recent pictures I posted (20th-21st event) are probably not showing anymore because I added another picture to the list, and perhaps the way it works it doesn't like that very much.

Tuesday Temp: 18/0
Wednesday Temp: 18/-2 (with a frost)
....

Moisture in the top metre of the soil is forecast to increase (18Z 29 jun 2011 to 06Z 07 jul 2011) come the 2nd (July).

Specifically, dates where conditions were/are conducive to rainfall:

20th-21st, 27th, 30th, 2nd-3rd July, 5th-6th July...at the moment.

Specifically, dates where rain has/is in likely to fall:
20th-21st, 30th, 2nd-3rd.
Posted by: Seina

Re: Streamflow Observations - 01/07/2011 12:48

I think there is going to be a significant change in runoff, at this stage smile , over the next 3 days.
Posted by: Seina

Re: Streamflow Observations - 01/07/2011 22:21

The GFS forecast maintained a large rainfall total for the 2nd-3rd period for several runs at anywhere from 35-40 mm up to 90-95 mm.
Posted by: Seina

Re: Streamflow Observations - 03/07/2011 15:33

Originally Posted By: -Cosmic- (naz)
I think there is going to be a significant change in runoff, at this stage smile , over the next 3 days.

I almost feel like issuing a severe weather warning myself, but won't.

There has been a significant change in runoff (streamflow), but there has been no where near enough rainfall to cause this; time of observations: 2.45 pm CST 3rd July 2011.
Posted by: Seina

Re: Streamflow Observations - 03/07/2011 22:05

In the end, the GFS forecast seems to have been relatively ok for yesterday; 15-20 mm.
Posted by: Seina

Re: Streamflow Observations - 06/07/2011 11:34

June 2011 Rainfall: 69.1 mm (Avg ~120).
YTD: 419.3 mm (9.15 am today).

Moderate to Major rainfall totals:

20th June, 26.5 mm.
21st June, 12.9 mm.
4th July: 21.9 mm.

Forecast vs. Obs

Conducive to rainfall:

All dates had conditions conducive to rainfall.

11th-12th May, Actual: 11 mm.
17th May, Actual: 0.1 mm.
22nd-24th May, Actual: 46.9 mm.
20th-21st June, Actual: 39.4 mm (gale force winds).
26th June: Audible change in streamflow: 9.35 pm.
27th June, Actual: Trace.
30th June, Actual: 0.3 mm.

1st July: Audible change in streamflow (unlikely due to rainfall): 5.10 pm.
1st July (unstable atmosphere), Actual: Started 7 pm: 0.7 mm.

2nd July (unstable atmosphere), Actual: 13.8 mm.

3rd July: Audible and visual change in streamflow (possibly due to rainfall): 2.45 pm.
3rd July, Actual: 3.9 mm.

4th July (unstable atmosphere), Actual: 21.9 mm (hail, thunder, gale force winds).
4th July: Audible and visual change in streamflow (more likely due to rainfall).

5th July (unstable atmosphere), Actual: 10.5 mm.

6th July: Audible and visual change in streamflow (reduced runoff, catchment still gaining soil moisture as it soaks in (9 am)).
6th July, Actual: 2.1 mm (9.15 am).

July Rainfall (9.15 am today): 52.9 (Avg ~100).
Posted by: Seina

Re: Streamflow Observations - 06/07/2011 20:59

Major change in runoff happening here. See the BoM website:

http://www.bom.gov.au/fwo/IDS60247/IDS60247.523714.plt.shtml
Posted by: Seina

Re: Streamflow Observations - 07/07/2011 12:59

It took about 3 mm for the change in runoff to start heading north in a hurry. Water was inches deep in some places (paddocks). Runoff prior to 5 pm (yesterday) was about 0.86 units...it's was 1.1 units @ 8 pm. On the 4th, it was 0.47 units.

Raining quite heavily here atm (12:20 pm).

Comparison 6th-7th July 2011 (3 Months)

Comparison 6th-7th July 2011 (Beginning of year)

Comparison 6th-7th July 2011 (Beginning of 2010)
Posted by: Seina

Re: Streamflow Observations - 07/07/2011 13:04

I don't have any reasonable photos of the river flow from 8 pm, but it's enough to say there river flow rate could have risen about half a metre in 3 hours.
Posted by: Seina

Re: Streamflow Observations - 15/07/2011 15:25

Just yesterday I had thought "what if"...I was thinking about snow this year...I looked at the pressure, 1027 hPa, hmm, sort of high, put not really that high, I think confused .

17th is looking interesting, a little blip on the map says the thickness and rainfall smile .
Posted by: Seina

Re: Streamflow Observations - 15/07/2011 15:50

Then again, it depends how much the pressure falls and how long it takes.
Posted by: Seina

Re: Streamflow Observations - 17/07/2011 13:59

My g'd @ the pressure vertical velocity...I think, negative for an entire run eek !

See the glossary smile .
Posted by: Seina

Re: Streamflow Observations - 18/07/2011 10:23

Originally Posted By: -Cosmic- (naz)
17th is looking interesting, a little blip on the map says the thickness and rainfall smile .

Little blip it was... 6.6 mm in 24 hours.
Posted by: Seina

Re: Streamflow Observations - 18/07/2011 10:35

That should be 5.6 to 4.30 pm.
Posted by: Seina

Re: Streamflow Observations - 20/07/2011 10:56

Could we be talking the 3rd of August for a major rainfall event?

And more importantly, could the pattern be shifting?
Posted by: Seina

Re: Streamflow Observations - 21/07/2011 14:12

The 1000-500 mb Thickness looks like it might be rising for a while...temperature increasing.
Posted by: Seina

Re: Streamflow Observations - 21/07/2011 14:23

Sub-Note:

Repeatedly relatively low overnight minimum may indicate "winter" is approaching. Hence a rise in the overnight lows may indicate and increase in conditions conducive the rainfall.
Posted by: Seina

Re: Streamflow Observations - 23/07/2011 12:47

Originally Posted By: -Cosmic- (naz)
Sub-Note:

Repeatedly relatively low overnight minimum may indicate "winter" is approaching. Hence a rise in the overnight lows may indicate and increase in conditions conducive the rainfall.

What I didn't mention was there is likely an "increase in conditions conducive to rainfall"...in this situation, as soon as the overnight low starts to rise.

That being today/last night.

[21st: Possible audible change in flow (~ 7 pm).]
Posted by: Seina

Re: Streamflow Observations - 25/07/2011 09:58

Streamflow started increasing this morning, both audibly and visually. 5.1 mm to 8.45 am.
Posted by: Seina

Re: Streamflow Observations - 26/07/2011 09:42

I just hope this early August possible major rainfall event is not an exaggeration...not just for the sake of streamflow.
Posted by: Seina

Re: Streamflow Observations - 26/07/2011 09:48

Originally Posted By: -Cosmic- (naz)
Streamflow started increasing this morning, both audibly and visually. 5.1 mm to 8.45 am.

I'm not sure whether this is due to rainfall...or something else.
Posted by: Seina

Re: Streamflow Observations - 30/07/2011 10:44

7.3 mm in convective activity overnight...very close to what the models (GFS) projected. Similar to the 6.6 projected last time.

Negligible change in streamflow...for now.
Posted by: Seina

Re: Streamflow Observations - 31/07/2011 14:41

Yesterday's top was 23 C, technically in the middle of winter. Currently around 20 C...
Posted by: Seina

Re: Streamflow Observations - 01/08/2011 10:20

Streamflow, in terms of orders of magnitude, just went into quite a significant decline overnight, dropping what seems quite significantly since about 6.30 pm last night. Pressure has also dropped...now around 1008-1009.

It is noteworthy, however, that the flow level rose before the decline.
Posted by: Seina

Re: Streamflow Observations - 08/08/2011 16:26

Written Saturday, 6th August 2011, Updated 8th:

We’ve had 5 consecutive days in a row of 21-24 C (the latter three being 24) … technically in mid-to-late winter.

Thursday’s maximum was 11, with an overnight low of 9 C.

Yesterday morning [Friday] it was 7, with 89% humidity @ 9.10 am.

Overall the maximum temperature dropped about 13 C in 24 hours from the 3rd to the 4th, although that may have been less than 24-hours judging by when the rain first hit (5.40 pm, Wednesday).

The minimum Relative Humidity on those days at or above 21-24 C averaged around 20-21%…Thursday it didn’t get below 80%, and yesterday [Friday] night’s overnight high seems to have been even higher (> 85%).

We’ve had 7 sub-zero frosts in all, 17/5, 1/6, 14/6, 29/6, 16/7, 21/7 and 22/7.

Over the course of the 22/7 to the 23/7, the temperature changed from 20/-6 to 17/6, a 12-degree turn around in the minimum. The following 4 days we received a total of 5.6 mm.

Apart from the 27th (with an overnight low of zero), minimums have been averaging greater than 6 C, and the averaged maximum has been around 19 (that is 19/6). The previous period (1/7 to 22/7), the average was 14/4…which means both have risen circa 22-23/7.

System total to 10.30 am (today) was 29.4 mm over 4 days.

[Update: 34 to 10 am, 8/8/11, 6 days]

Streamflow started increasing around midday Thursday (according to BoM)…reflected in ground obs here, and continued to increase overnight yesterday.

Forecast had in excess of 70 mm over a 24-hour period on the 00Z04aug2011 to 12Z11aug2011 run…not sure about that – it didn’t really happen, but streamflow did change very noticeably.

Water was easily an inch deep on places in paddocks around 2 pm Thursday.

Latest MRF forecast [Friday] had [the maximum] temperature plummeting to remain below 18 C for much of August…as this weather continues, it could become increasingly likely.

Very interesting set of events over the last week or so…could have been reminiscent of a late start to winter rather than rain late in winter, especially with an overnight low of -6 (a record by the looks) coming only days out from this event (3rd-present).

Streamflow is no where near the highest levels recorded last year. Yet at the same time it has only taken a few millimetres for the river to respond (3-4 mm on Friday morning), which implies the catchment is near enough to saturation that it’s not going to take much in coming weeks if there is a major (+50-mm) event. It is (seems) rather remarkable that despite the general lack of solid (+20-mm) rainfall events over the last month or so, the catchment is still very near the runoff threshold. It seems to further imply it’s not really as dry as thought…even though evaporation can be significant at times.

The question, where is all this water coming from? Or how is it being retained so efficiently, if it is? Perhaps the rate of loss of groundwater to down-slope sources is not as pronounced? It seems a very complex system.

Back at the start of this thread, I mentioned river levels had been the lowest on record for 25-30 years last March 2010…so how have we come full circle to find the threshold for streamflow is not that far away?

It’s a real contrast to have streamflow increase substantially in magnitude within hours of rain falling while in March/April 2010 the same rainfall would have just sunk straight in.

In any case, unless winter is late this year, it’s going to take a hell of a downpour or moderate to heavy rain over 2-3 days to reach last year’s peak streamflow levels. The difference between the peak for this yesterday and that last year is in the order of 2-3 metres…not even reaching levels of the 7th of last month.

One thing seems to be abundantly clear from the GFS outlook…the pattern has changed somewhat (I’d like to think a little more than somewhat, but again we’ll see smile ). Probably won’t be seeing +20 degrees again for a while. I guess that might mean rainfall becomes more substantial.

[Update: Latest MRF forecast shows temperature continuing to remain below 20 degrees, for at least a week]

7th August 2011, Looking North
Posted by: Seina

Re: Streamflow Observations - 15/08/2011 20:26

There is what appears to be a distinct inter-seasonal trend in the pressure going on...over years, which may go some way towards explaining why 2006 was a drought year (when the winter rains did not properly eventuate) and why a similar trend is unfolding this year...

This is directly related to runoff through how much rainfall is sufficient in a given year to "break" the trend.

It seems to be related to high-pressure systems. The next few weeks, or even days, could tell us whether this year's trend is likely to continue in the way it is, or whether streamflow will become much more substantial heading into spring.
Posted by: Seina

Re: Streamflow Observations - 17/08/2011 09:51

As of 20 past 9 this morning, the local river level is about 0.5 metres from the top of the bank in places. Another 20-40 mm within 12-24 hours would likely see surrounding paddocks start to flood.
Posted by: Seina

Re: Streamflow Observations - 17/08/2011 12:33

3.44 pm, 13/8/11:



3.45 pm, 13/8/11:



4.18 pm, 14/8/11:



17/8/11, 7.07 am:



17/8/11, 7.10 am





Posted by: Seina

Re: Streamflow Observations - 17/08/2011 17:45

I am becoming suspicious we're due for a cold spell, this year.

I'm a bit uncertain about the details, but the record low of -6 C earlier on this winter is a hint, along with the frosts prior to it.
Posted by: Seina

Re: Streamflow Observations - 17/08/2011 17:57

Edit:

The frosts wiped out species of grass that couldn't deal with the sub-zeroes.

Yesterday the atmosphere became conducive to the conditions for a cold spell I'm talking about. Almost sleet-like rain in a brief sharp downpour lasting a few seconds.
Posted by: Markus

Re: Streamflow Observations - 18/08/2011 21:36

interesting that it wiped out some grass, places round here diped to -7/-8 and the grass seems to have delt very well really.
As for that cold spell last night when the cold pool really came through we had 4.5 degrees and rain, never been that cold before with rain here that i can remember. Wind chill made it feel below 0 never been so cold before. Altitude was 500 m for the record
Posted by: Seina

Re: Streamflow Observations - 22/08/2011 10:48

Interesting observations on grasses dealing with sub-zeroes well smile . Perhaps it is a more localised phenomenon.

Whether we have cool, dry spring, a cold, wet one or a warm wet one (in terms of runoff) will likely depend significantly on whether we get heat troughs or pressure troughs leading into the next season.

The temperatures (maximum and minimum) are starting to rise, the pressure has been following suit…but can only do so for so long.

Edit: Strictly speaking, this year's streamflow has been either about average or below…I tend to think below.
Posted by: Seina

Re: Streamflow Observations - 25/08/2011 11:01

#945820 - 31-01-2011 01:41 PM

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Special Note 31-1-11:

=>Serious amounts of energy in the atmosphere, and being released by it. ???

Global warming, no...potentially something else...

Another 40-degree day (3 pm).

Just as a note of benefit, if I understand this correctly, specific humidity trends inversely with surface pressure.

Current Pressure: 990, RH: <20%. [Think I might get some photographic evidence of pressure.]


#960508 - 14-02-2011 12:09 PM

Originally Posted By: -Cosmic- (naz)
Supplementary Note:

All these anomalies that seem to be occurring in the observations are threatening to culminate in something…

[I'm talking within a year].

P: still 1013 hPa.

I have maintained we're could be due for a cold spell this year...and still think it's a possibility, to put it lightly.

2 out of the last 3 days have been near-frosts. (Min: 1 deg C).
Posted by: Seina

Re: Streamflow Observations - 25/08/2011 11:12

44.7 mm over the period 15th to 19th, major change in streamflow on the 17th.
Posted by: Seina

Re: Streamflow Observations - 30/08/2011 22:26

There was major flooding in September 1991, August 1992, December 1992, and possibly in September 1986.

We may yet see this kind of runoff in the next decade…it all depends on what weather and climate patterns prevail…

It’s interesting to note the SAM (Southern Annular Mode) is slightly increasing in the last decade or so.

It is possible a fraction of local climate and weather variability can be accounted in this phenomenon.
Posted by: Seina

Re: Streamflow Observations - 31/08/2011 11:13

According to the latest Bureau observations, streamflow has levelled out to be slightly higher than that during the period 15/7 to 31/7, implying the catchment is closer to saturation and retaining more soil moisture than during that period.
Posted by: Seina

Re: Streamflow Observations - 01/09/2011 13:50

Last year’s streamflow [magnitude] shows this year’s [winter] as a small “blip” on the graph in comparison…in the week ending 14th-21st/7.

Rainfall and Estimated Streamflow, 1/1/2010 to 22/08/2011

…note however, the peak [flow] in 2010 occurred in September.
Posted by: Seina

Re: Streamflow Observations - 01/09/2011 22:18

I'd say we're just about due for another major rainfall event within a week or two.
Posted by: Seina

Re: Streamflow Observations - 04/09/2011 11:33

Originally Posted By: -Cosmic- (naz)
I'd say we're just about due for another major rainfall event within a week or two.

Judging by the latest GFS forecast (18Z 03 sep 2011 to 06Z 11 sep 2011) I think that might be a bit of an understatement...will see smile .
Posted by: Seina

Re: Streamflow Observations - 04/09/2011 16:39

Just for interest’s sake, some streamflow estimates I carried out indicate the last major change in runoff occurred on the 3rd of August 2004. This was the Rainfall during that week:

Thursday 29 1.2
Friday 30 0
Saturday 31 1
Sunday 1 9
Monday 2 33.5
Tuesday 3 52.6
Wednesday 4 28.9
Thursday 5 0.8

Notably, for this period, the minimum temperature remained steady over the 4 consecutive days starting the 2nd, at 5 degrees.

The interesting thing about the streamflow estimate is that had the above rainfall not fallen at all in the time and magnitude it did…a trend of consecutive low-flow years may have continued. In other words, it was likely a rather large streamflow peak that may have dwarfed those of years prior and up to most recently (2010).
Posted by: Seina

Re: Streamflow Observations - 10/09/2011 14:17

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
I'd say we're just about due for another major rainfall event within a week or two.

Judging by the latest GFS forecast (18Z 03 sep 2011 to 06Z 11 sep 2011) I think that might be a bit of an understatement...will see smile .

Days which may have higher probabilities for significant rainfall include the 15th and 19th.
Posted by: Seina

Re: Streamflow Observations - 10/09/2011 22:12

The said rain events – GFS forecast 18Z 03 sep 2011 to 06Z 11 sep 2011 – eventuated, however it has not been enough…in magnitude…to significantly change streamflow. I was suspicious the forecast for 60-80 mm in a short period of time would be down graded…what happened was it appeared to get down graded and then spread over several days. Rainfall to 7 pm tonight is 11.5 mm…since the 3rd, most of that falling in the last couple of days.

This has been a rather cold spell in comparison to a week ago when temperatures were in the mid-to-low 20s. Since Monday (5th), they have been below 20 degrees, and since the 6th, very much below (lowest maximum being 12 degrees). The overnight lows have also risen slightly – for 5 consecutive days (to today) the minimums have not fallen below 3 degrees. This might change in the foreseeable future, but for now conditions are conducive to sporadic stream showers, sometimes heavy (like the last one around 7.20 pm).

These conditions are not yet conducive to particularly large and prolonged showers/rain…but the dates mentioned in my last post might suggest that if current conditions continue for some time, it may become increasingly likely.
Posted by: Seina

Re: Streamflow Observations - 20/09/2011 21:23

Slight increase in streamflow following a rather intense but short-lived system over the period 19th-20th.

As of the 19th, a forecast for widespread rain across much of Southeastern Australia was evident on the long-term forecast with signficant atmospheric moisture content, stretching from approximately Hawker in SA's Mid North to Gippsland in the far east. The rain covered the period approximately 27th September to 1st October.
Posted by: Markus

Re: Streamflow Observations - 20/09/2011 22:02

Interesting, they were hinting at rain during that period on the news, lets hope it eventuates
Posted by: Seina

Re: Streamflow Observations - 23/09/2011 14:56

A lot has happened in the last couple of years (streamflow-wise) which has led me to question what might be going on below the surface (underground), and what might be about to happen in 6-12 months.
Posted by: Seina

Re: Streamflow Observations - 25/09/2011 12:06

Originally Posted By: Markus
Interesting, they were hinting at rain during that period on the news, lets hope it eventuates

Yes, very interesting.
Posted by: Seina

Re: Streamflow Observations - 25/09/2011 14:48

Originally Posted By: -Cosmic- (naz)
5 consecutive days

...

the minimums have not fallen below 3 degrees.

Make that 19, ending last night.

Streamflow has fallen away considerably. Pressure is currently around 1019 hPa.
Posted by: Seina

Re: Streamflow Observations - 27/09/2011 17:06

Originally Posted By: -Cosmic- (naz)
Pressure is currently around 1019 hPa.

Currently 996 hPa.
Posted by: Seina

Re: Streamflow Observations - 27/09/2011 22:05

At this stage, the latest GFS run (06Z 27 sep 2011 to 18Z 04 oct 2011), has almost 20 mm forecast for tomorrow morning and into the afternoon, and about 40-45 mm forecast for a period late Thursday into Friday. Another 10-15 mm is forecast Friday into Saturday. The wettest period looks like late Thursday to early Saturday morning. The change in runoff for the period Thursday night into Friday is (in magnitude) considerable and abrupt (about 8 times current runoff levels). There is a smaller peak a day or two after, but much lesser (maybe 2 twice as much).

The signs are beginning to look more encouraging for a major runoff event later on this week, once the initial falls start soaking into the soil.
Posted by: Seina

Re: Streamflow Observations - 29/09/2011 23:47

There may some potential for flooding in the region mentioned in post #1013495 - 20-09-2011 09:23 PM in the coming week or two.

37.3 mm to 11 pm today, starting yesterday.
Posted by: teckert

Re: Streamflow Observations - 29/09/2011 23:51

I reckon you are looking at about 30-40mm in the next 24 hours Carl...
Some models suggest similar mid next week, but I'd be more going with GFS at this stage and maybe 10mm during wednesday.
Posted by: Seina

Re: Streamflow Observations - 30/09/2011 00:01

Pretty relentless stuff. Has anyone got a reasonable ETA on this next bit? I might need it.
Posted by: Seina

Re: Streamflow Observations - 30/09/2011 00:16

Originally Posted By: -Cosmic- (naz)
Pretty relentless stuff. Has anyone got a reasonable ETA on this next bit? I might need it.

Got it smile .
Posted by: Seina

Re: Streamflow Observations - 30/09/2011 10:22

Originally Posted By: -Cosmic- (naz)
There may some potential for flooding in the region mentioned in post #1013495 - 20-09-2011 09:23 PM in the coming week or two.

37.3 mm to 11 pm today, starting yesterday.

Going by GFS, it might cover our area as well.

2 inches and counting. Streamflow starting to respond more.
Posted by: Seina

Re: Streamflow Observations - 30/09/2011 13:15

Streamflow along the Onkaparinga is beginning to respond more rapidly.
Posted by: Seina

Re: Streamflow Observations - 30/09/2011 20:30

I would say we need another 10-15 mm in maybe an hour or two or 20 mm or so in 24 hours to start to see the puddles in the paddocks connect with the river flow.

Whether that actually happens in another question.

Real gumboot weather.
Posted by: Seina

Re: Streamflow Observations - 02/10/2011 21:07

A bit over 2.4 inches (60 mm) to yesterday. Moderate change in flow (few metres in height terms to the river bank). 10-15 mm didn't eventuate, possibly unrealistic in the end.

Soil moisture is up and paddocks have become very green in last day or two. Overnight temperatures are plummeting again, pressure rising (~ 1015 hPa). Likely more rain to come mid-to-late this week.
Posted by: Seina

Re: Streamflow Observations - 04/10/2011 20:50

More than the fact of soil moisture increasing being interesting, is the temperature trend in the latest GFS run (00Z 04 oct 2011 to 12Z 11 oct 2011). The trend appears to be linear. But that's not the most interesting thing about it. It's the fact that the forecast trend is down that's most interesting, at the moment.
Posted by: Seina

Re: Streamflow Observations - 05/10/2011 15:14

If anyone has any records of minimum temperature or humidity/vapour pressure they'd like to share, I'd interested to know the linear trends in each, starting 1/1/2011 to 9/4/2011, and 10/4/2011 to now smile . I'm getting two distinct trends in each for each period.
Posted by: Seina

Re: Streamflow Observations - 07/10/2011 22:42

Written two days ago (5/10/11), modified today:

Ok, a bit closer (short-notice) this time…but still there:

The GFS (06Z 06 oct 2011 to 18Z 13 oct 2011) run shows 70-80 mm Saturday Night-Sunday Morning to perhaps midday. The run (00Z 07 oct 2011 to 12Z 14 oct 2011) had perhaps 30-35 mm.

Change in runoff (only 2-3 days out) is significant (about 4 orders of magnitude at the moment – 5/10/11).

Update 7/10/11: 10 times current flow levels, so a little less.

A sharp, abrupt change in soil moisture…almost 10% by catchment area (5/10/11).

Update 7/10/11: again, a little less.

Forecast had increasing rain since about the 3rd of October…it might still maintain until tomorrow (Saturday), but I’m a little sceptical at the moment (7/10/11).

One to keep an eye on smile .
Posted by: Seina

Re: Streamflow Observations - 12/10/2011 17:22



Streamflow 11th May 2010:







Streamflow 4th September 2010:



Streamflow 17th August 2011:

Posted by: Seina

Re: Streamflow Observations - 14/10/2011 09:38

Ok, let's try this again:

Special Note, Today's Forecast: "Possible Thunderstorm."

=> Observing radar/satellite...

Thunder heard...heavy rain!
Posted by: Seina

Re: Streamflow Observations - 17/10/2011 11:03

4.5 mm from the last event (14th)...not much of a change.

On another note, I don't think I've seen the pressure this high (today) for quite some time (~1029), after being only 1008 a couple of days ago. Last night's overnight low of zero (with a frost) was also contrasting in the sense that the last time it was around that mark was the 3rd...the average min since the 3rd being about 8 degrees.
Posted by: Seina

Re: Streamflow Observations - 17/10/2011 13:11

Another reason recent soil moisture estimates indicate the sub-surface is quite damp is because a local pond still contains maybe 0.5-1 metre of water. Although it is bit early to tell, this slightly suggests the level at which the moisture in the soil is at the moment, if underground pressure due to mass was removed, would be quite high. This means if we drilled a hole down to the level of moisture in the soil (saturation), the water could rise up the column a long way. Whether it would become artesian (overflowing) is another question.

It's mid October, December is a while away. Depending on the above, and pressure changes (dropping pressure heading into summer), we could hypothesise there is a slight suggestion of high humidity, and atmospheric moisture, at the moment!
Posted by: Seina

Re: Streamflow Observations - 21/10/2011 21:42

Small ants building some nests along the upper river bank for some reason. Not just a few ants though, hundreds of them confused . Humidity is continuing to increase on a daily basis.

The ants building nests along the river bank could be another aberration…or they know something we don’t.

Revision:

Edit: S’’t @ the forecast peak for the 25th eek – 00Z 21 oct 2011 to 12Z 28 oct 2011 run! Only 3-4 days out! 130 mils! I guess that's what you call rain in plain speak.
Posted by: Seina

Re: Streamflow Observations - 23/10/2011 11:12

Interesting...rain forecast for tomorrow.
Posted by: Seina

Re: Streamflow Observations - 23/10/2011 12:52

Some I would like to make a proper note of:

At a glance, the pressure could have dropped on the 17th, heading into late spring-early summer. As it stands, it appears to have been the highest-recorded pressure since late-August last year (2010). In other words, it looks like it was higher than the winter max. If anything this possibly represents a departure from what might have been expected to occur (the pressure continuing to fall, steadily, as it had been doing since the 23rd of August, this year). This little 1029 hPa on the 17th is a little out of sequence unless one assumes that (a) the pressure is going to remain relatively high for perhaps a few weeks to a month, or (b) the trend of the pattern of the last two years will not continue as envisaged into summer – that is a seasonal variation are per usual (summer, autumn, winter, spring).

But then again there was also another blip in the time series, circa 7th-12th March 2010, when the pressure decided to buck the prevailing trend and first head south (1002), then north (1029, again). This one (17th) is a little more dramatic, but the “principal” of bucking to trend is similar. Assuming the current trend continues and the 1029 is statistical aberration (not sure about that), we’ll be at summer-type pressure by December (per usual). Assuming the 1029 is not a statistical aberration (quite possibly), we could be looking at a relatively mild-to-cool period of perhaps 2-3 months (that is moderated, sultry conditions) (nearing the end of January).

Update:

The pressure is now around 1005. The maximum pressure last summer was about 1018, so well below the summer maximum. However, this is not the middle of summer, even if winter has officially passed. Another interesting observation – yesterday’s max: 30 degrees with sultry conditions…that is, warm and extremely (I would go so far as to say possibly unusually) humid. The surface-heating was immense, even though other factors such as convection were somewhat less.

This is the middle of spring, and apart from a few blips here and there, one does not necessarily expect to see blips of this kind (pressure, humidity) on a regular basis.

The ants (same species) are continuing to build their nests (they have increased in size) in different places…some hundreds of metres apart.
Posted by: Seina

Re: Streamflow Observations - 07/11/2011 13:49

Ants will do what ants do (find food and build nests) smile .

...some forecasts are suggestiing rather heavy falls in Central SA over the next 24 hours, and more so the next 48 hours.
Posted by: Seina

Re: Streamflow Observations - 11/11/2011 11:32

Originally Posted By: -Cosmic- (naz)
Ants will do what ants do (find food and build nests) smile .

...some forecasts are suggestiing rather heavy falls in Central SA over the next 24 hours, and more so the next 48 hours.

Make that 72 hours in the Mallee...severe storm(s) went through causing considerable damage nearer the border, made the news last night (ABC).
Posted by: Seina

Re: Streamflow Observations - 14/11/2011 10:48

Streamflow has remained about stagnant for the past few weeks, barely changing at all (neither significantly rising nor falling). The humidity has also been reasonably high with some atmospheric instability. There was an electrically-active thunderstorm yesterday which dumped half a mm in the area in about 5 mins late morning, but it was enough to affect runoff noticeably. Conditions have been conducive to rainfall on and off, with some thundery showers during the afternoon on the day of the wild weather in the mallee, but still any rainfall to date (this month) has been mediocre. The upper soil is still quite wet and dark in texture (I suspect clay-loam), the lower layers a little drier and lighter in colour (sandy).

I’m not sure that this summer is going to be particularly dry and hot, as while temperatures have been quite mild (hovering around 30 degrees of late), the fact the river level has not changed much and the high humidity with those temperatures (as well as the instability) seems to mean there’s still a lot of antecedent moisture remaining in the catchment – antecedent meaning from previous rainfall events. This period leading into summer normally starts to get a little wetter. Although that is not a guarantee of a wet start to summer, it happens often enough on an annual basis to have some confidence in it.

The green growth in the area is also prolific – grass has/is been cut and paddocks readied for summer. It’s a little reminiscent of this time last year.
Posted by: Seina

Re: Streamflow Observations - 19/11/2011 10:00

Ok, the barometric pressure has risen about 10 hPa overnight (from 992 to 1002 - it had been well above 1000 hPa for some time before dropping), so there is now an increased chance of thundery activity or rain. Temperature is currently 16 degrees, with 82% RH and light drizzle.
Posted by: Seina

Re: Streamflow Observations - 21/11/2011 17:55

Make that a flat 16 degrees all day Saturday until around dusk, with light to fine drizzle/rain (trace recorded). Vegetation growth is still strong.

Could have put a date on that rainfall probability, but given many projections are indicating many different things, I figured give it a week from the time of the post...at least then it will include the expected coming period of mild-to-cool conditions (3-4 days).
Posted by: Seina

Re: Streamflow Observations - 22/11/2011 18:59

Re: GFS 00Z 25th of November 2011.

Sub-Note:

Is reminiscent of (if there is anyone who can recall) of the morning of the 8th of December 2004.

http://nomad3.ncep.noaa.gov/ncep_data/index.html (under forecasts)

GFS High Resolution (0.5 degree, 1 week): plot.

21st of November 2011, gfs_master_18z.ctl, Map

PWATclm, 00Z 25th of November 2011, Aust

Plot (opens a separate window)
Posted by: Seina

Re: Streamflow Observations - 23/11/2011 15:52

Mid-to-late Spring, 2011:

Taken 17th of October (~ 9 am), relatively high pressure.



Taken 17th October (~ 3 pm), looking north-northwest on the eastern side of the Onkaparinga River.



Taken 21st of October (~2.50 pm), looking upstream…strong vegetation growing in riverbed.



Taken 21st of October (~2.50 pm), looking downstream.



Taken 21st of October (~3 pm), looking southwest. Some long grass in surrounding paddocks. Dense vegetation growth near river.



Taken 28th of October (~ midday), looking northwest. Turbulent skies, something might be developing.



Taken 28th of October (~ midday), looking northwest. Turbulent skies getting closer.



Taken 28th of October (~ midday), looking southwest. Looks like it’s sliding southwest.



Taken 5th of November, looking upstream…even stronger vegetation growing in riverbed.



Taken 5th of November (mid afternoon), looking southwest…virga.



To be continued...
Posted by: Seina

Re: Streamflow Observations - 24/11/2011 12:28

Looks like it's going to cool down a bit over the next few days (below ~20 C). Pressure is currently 1020. Precipitable water could well peak in that time smile .
Posted by: Seina

Re: Streamflow Observations - 24/11/2011 12:57

Originally Posted By: -Cosmic- (naz)
Precipitable water could well peak in that time smile .

If anyone gets a chance, see if the precipitable water from 00Z 18th of November 2011 to more recent runs for time: 00Z 25th of November (map of Australia) can be compared in the link provided above. It looks pretty solid from here.
Posted by: Seina

Re: Streamflow Observations - 26/11/2011 14:52

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Precipitable water could well peak in that time smile .

If anyone gets a chance, see if the precipitable water from 00Z 18th of November 2011 to more recent runs for time: 00Z 25th of November (map of Australia) can be compared in the link provided above. It looks pretty solid from here.

The heaviest rain (so far – this system appears to be petering out circa 1:30 pm) was either early in the morning yesterday when the humidity peaked, or this morning at around 11:50 am, when we recorded 1 mm in 5 mins. Pressure is still relatively low (1006, 12:30 pm)…

Depending on the conditions, a moderate-to-significant rise in the atmospheric pressure following a fall to reasonably low pressure (say between 1000 and 990) would constitute a change in regional patterns (that is this area of the Adelaide Hills, where rainfall within say 1 km has a very sharp variation – just yesterday around 1.5 mm fell in a short period just 2 km east (BoM), we barely got 0.3 mm). A change in pattern usually means either the onset of heat-wave conditions, or rain. In this case it was rain. It didn’t stop raining yesterday…apart from a brief spell around midday. The humidity picked up, temperatures between say 15 and 25 degrees, maybe a little lower yesterday (18)…currently 20 degrees, mildly humid (65%), 2 pm.

All up, 15.1 mm to 1 pm today.

Rain can also occur directly in a pressure drop, particularly the more dramatic ones (to less than say 985), or with a trough present and much near-surface heating, however those changes are more associated with the passage of fronts and the development of the north-west cloud band.

Near-surface heating is particularly important when the humidity is lower (say below 70-80%) as it provides the local latent heat flux necessarily to kick off sporadic showers (1 mm in 5 mins).

In terms of the effects on runoff, there was enough rain yesterday that puddles did begin forming, but while vegetation growth is retaining some moisture, the soil is becoming more and more visibility parched – whether this is due to drier conditions or more solar heating and sultry conditions I would say is open the question. The river is certainly higher than I would have thought for this time of year, still flowing. The humidity is definitely palpable.

In terms of streamflow we’re talking weeks to months for things to eventuate – that’s about the span of the antecedent conditions for soil moisture from each rainfall event (that is, assuming it doesn’t evaporation too much or the humidity fall to 10-20%).

Immediate, significant changes in streamflow will only happen if these antecedent conditions have been significant enough for long enough, or if there is a significant thunderstorm dropping say 20-30 mm in an hour or so.

Three keys variables to keep an eye on every now and then could be precipitable water, latent heat flux and 1000-500 mb thickness.

The first gives the potential moisture for rain, the second relates to evaporation and convective activity and the third is more associated with fronts and cut-off lows.

In this region it is possible the actual evaporation could be estimated from the local maximum and minimum temperatures, the precipitable water, from that pressure and the atmospheric pressure…the thickness relating the scale height of the atmosphere through the pressure and temperature. The regional wind direction (observations, not measured) also has an impact on the chance of rain, and in which season.

Assuming all else remains the same (fixed), especially the pressure (Force per square metre of area) as the temperature falls, the density (kilograms per cubic metre) increases (due to humidity, I think I’ve got that right?), and the precipitable water then increases and the air can retain less moisture. This forces the humidity up further. The trigger for this fall in the temperature is a drop in the latent heat flux (less evaporation), increased cloud cover, and greater water vapour concentration. The trigger for all of these appears to be more moisture…which is what we seem to be getting more of atm.
Posted by: Seina

Re: Streamflow Observations - 02/12/2011 21:58

There has been a rather dramatic turn around in the pressure over a period of 24-48 hours – 29th of November to 1st December. After remaining at 988 hPa from a few hours, in the following 24 to 48-hours period it rose to be in excess of 1020 hPa.

It’s currently sitting on 1013 hPa (~ 8 pm).

Continuing…

Taken 9th of November (~ midday), convection to the north-northwest.



Taken 9th of November (~ midday), same convection, shifted east.



A photo I took on Friday the 11th of November 2011 looking north-west towards Lobethal has led me to wonder about the medium-term prospects of significant falls. The photo shows what appears to be high altocumulus clouds, a very fine, extensive deck with the checker pattern.



A chance to see what the soil was like underground…12th of November (~ midday).



Streamflow…21st of November (~ 7.30 pm)



Sunset, 21st of November…



Rough Sunset Panorama, November 2011
Posted by: Seina

Re: Streamflow Observations - 05/12/2011 19:46

The next week or so looks interesting in terms of the quantities of moisture forecast to be present in the atmosphere…and runoff.

Temperature doesn’t seem to be increasing much (to maybe 30-35)…followed by a decline.

Humid, sultry…maybe wet.
Posted by: Seina

Re: Streamflow Observations - 13/12/2011 17:19

Written 9th December 2011:

Originally Posted By: -Cosmic- (naz)
The next week or so looks interesting in terms of the quantities of moisture forecast to be present in the atmosphere…and runoff.

Temperature doesn’t seem to be increasing much (to maybe 30-35)…followed by a decline.

Humid, sultry…maybe wet.

No significant visual or audible change in flow. Temperatures more-or-less up to 35 degrees by Thursday. Mostly below 20 degrees leading into Friday, and Saturday.

One thing I will note about the pressure though:

I don’t know whether it is thought pressure changes occur consistently at the same rate or not…but from what I’ve witnessed, it certainly doesn’t seems to be the case.

The pressure can change quite considerably and abruptly, within a very short period of time (minutes), or it can take several hours to days to change. It is that dynamic. For the period in question (9th-11th) the [surface] pressure has remained relatively steady at around 995 hPa. The pressure is probably going to start rising sooner rather than later (within a day or two, maybe even hours given this phenomenon).

Update (11th): Pressure now rising gradually.

[A yet-to-be validated low-resolution experimental rainfall model (specific to this region) I’d been looking into didn’t show much rain for this period (9th-11th)…when I checked on the 5th. 5 days later (10th) there is a slightly higher peak around the 18th-19th, maybe 20-30 mm, which I honestly didn’t believe to start with. The actual amount (for that peak) varied from about 200 mm down to about 5 mm, and shifted form the 25th to the above dates. It indicates the pressure initially starting to drop by about the 15th, and then rising with 2-3 days before a major rainfall peak around the dates shown. For now the pressure is slightly rising].

Update (13th): Latest short-term forecast (00Z13DEC2011 to 12Z20DEC2011) for this area has about 235 mm for the Saturday afternoon, with a major change in runoff (up to ~ 3.5 kg/m2). Pressure (mean sea-level) is expected to fall quite a lot (down to perhaps 1000 hPa (surface perhaps 980-990)). Precipitable water is forecast 35-40 kg/m2.

As always, time will tell with these things. Yesterday (12th) we had a brief period of intense drizzle where the temperature dropped from 17 to 15 degrees from about 6:25 pm onwards. While there was no runoff, it seems to be an indication that there is or has been a lot of moisture in the atmosphere.
Posted by: Seina

Re: Streamflow Observations - 15/12/2011 10:46

Looks like moisture could well be penetrating down into the lower layers of the soil...not sure, but perhaps 50-60 mm. Precipitable water is beginning to become significant - 40-45 kg/m2, mean sea-level pressure barely dropping below 1000 hPa.
Posted by: Seina

Re: Streamflow Observations - 15/12/2011 23:15

One thing about models: don’t expect a trend to follow from one year/month/week/day to the next in a linear fashion…the system behaves non-linearly.
Posted by: Seina

Re: Streamflow Observations - 16/12/2011 11:48

Forecast appears to be steady, expect much rain smile ! Looks like the soil might be a benefactor this time...
Posted by: Seina

Re: Streamflow Observations - 16/12/2011 15:18

Originally Posted By: -Cosmic- (naz)
Forecast appears to be steady, expect much rain smile ! Looks like the soil might be a benefactor this time...

Some may notice in the above I did not indicate how much I thought was going to fall. Conditions first need to become conducive to rain, and then rain must actually fall at or above a certain rate for a given period of time.
Posted by: Seina

Re: Streamflow Observations - 17/12/2011 09:43

Sticking with my original thoughts (#1043773 and #1044246).
Posted by: Seina

Re: Streamflow Observations - 19/12/2011 15:32

If anyone is interested:

Streamflow, 21st November 2011:



Streamflow, 18th December 2011:



A lot of debris around the place today (small fallen branches).

34.1 mm system total.
Posted by: Seina

Re: Streamflow Observations - 11/01/2012 20:32

Updated 11th of January 2012:

Note of benefit: Estimates are theoretical with a large margin for error, not actual. Rain rate footage for the event on the 7th of January can be found here:



Written 4th of January 2012:

An analysis of the last two years of daily rainfall observations – 1st of January 2010 to 31st of December 2011 – indicates a difference in the number of days on which 5 mm or more was recorded. Commencing approximately the 12th of May 2010, and 2011, ending the 31st of December respectively, 40 days recorded greater than or equal to 5 mm, whilst for 2011, 26 recorded at or above 5 mm. In contrast, estimates of soil moisture may indicate greater moisture content overall (on average) for 2011, than for 2010 (138 and 123 mm respectively). The peak in soil moisture estimates which occurred during the peak in winter rainfall (and runoff) during 2010 indicates the potential of up to 200 mm present. In 2011, a similar peak did not occur, however estimated moisture levels appear to have maintained (relatively constantly) at between 100 and 150 mm, although mostly closer to 150 mm. In the latter part of 2011, soil moisture estimates began to fall towards 100 mm (from about the 30th of September onwards). The trend of near-constant soil moisture estimates may have, in part, been due to the significant rainfall events of February and March 2011; on Friday the 18th of February, 57.4 mm was recorded, on Tuesday the 8th of March, 58.4 mm. These events alone contributed significantly to soil moisture estimates, if not runoff directly. Direct runoff for 2011 was significantly down on 2010. Long-term stream flow estimates appear to indicate peak winter flow in 2010 may have been up to 3.5 to 4 times the magnitude of flow in 2011. Rainfall observations and trends are also supported by variations in an experimental maximum and minimum temperature dependent latent heat index, which, while highly complex, for the most part seems to reasonably represent probable falls for this area for the given 2-year period.

Update 9th of January 2012:

The local river is slowly but surely drying out. A rain event on the 7th was only slightly enough to contribute to direct runoff, most soaking into the soil in the short period of time it did occur. Heavier falls appear to have been recorded to the south and west. The river water level has receded half to one metre since the last significant rainfall event (>20 mm). The last significant rain event of greater than 20 mm occurred on the 17th of December 2011.
Posted by: Seina

Re: Streamflow Observations - 22/01/2012 12:41

Note 22nd January 2012:

Surface pressure (1006 hPa, 12 noon) is sufficiently high enough, humidity sufficiently low enough (~20%) and temperature rising enough (currently approaching 34 degrees) for conditions to become conducive to significant moisture advection and convective activity. Currently very light winds.
Posted by: Seina

Re: Streamflow Observations - 26/01/2012 19:10

Originally Posted By: -Cosmic- (naz)
Note 22nd January 2012:

Surface pressure (1006 hPa, 12 noon) is sufficiently high enough, humidity sufficiently low enough (~20%) and temperature rising enough (currently approaching 34 degrees) for conditions to become conducive to significant moisture advection and convective activity. Currently very light winds.

Period end: 25th January after humidity increased. Trace recorded on the 23rd.

Latent heat estimates indicate moderate-to-substantial rainfall for the period starting tomorrow ending approximately 30th-31st (first noted 21st). Precipitable water for the period appears to be increasing substantially, particularly on the 28th and 29th. The temperature appears to increase slightly before falling somewhat by the end of the month.
Posted by: Seina

Re: Streamflow Observations - 02/02/2012 21:53

Originally Posted By: -Cosmic- (naz)
Latent heat estimates indicate moderate-to-substantial rainfall for the period starting tomorrow ending approximately 30th-31st (first noted 21st). Precipitable water for the period appears to be increasing substantially, particularly on the 28th and 29th. The temperature appears to increase slightly before falling somewhat by the end of the month.

There were moderate-to-significant falls in the Greater Adelaide Area over the period 28th-31st, and since the 29th when stream flow was thought likely to peak (for the period)…but not in the Woodside area specifically. In fact no rainfall (other than a trace) was recorded locally until the 30th. That is 1 mm fell 30th to 31st.

A precipitable water estimate from an earlier calculation (28th) showed quite a significant difference when compared to GFS, by more than 10 mm (GFS being higher). It could have meant little, being a relatively simply calculation based on vapour pressure and barometric pressure, but then it could have been something.

The temperature dropped to remain in the mid-to-low 20s with west-to-south-westerly winds and a cool change after about the 30th-31st. There was a period prior to the 30th characterised by sporadic thunderstorm activity late in the afternoon into the early evening which tended to fall abruptly (in a deluge) within a period of 30 minutes or less. Conditions were moderately conducive to a thunderstorm event/period, but I believed anything conducive to a significant impact on stream flow was highly unlikely (we’re talking many inches over a longer period of a couple of days). So while there was a chance of an impact to stream levels, this became more remote with each passing day from about the 28th.

I was also somewhat reluctant to revise the above quote to peak on the 30th-31st (defined by the cool change) because the drop in surface pressure to 984 hPa prior to the cool change (correct reading, which is approximately 998 adjusted to mean sea-level) was not synonymous with the sporadic nature of the thunderstorm activity (which appears to have been very localised, as opposed to widespread).

I feel there is now an increased chance March-April 2010 river conditions being reached or exceeded (i.e. severely low flow levels). While there is every possibility this synoptic pattern could be broken within weeks or months, with each passing day without rain, the probability of a robust change in the patterns falls, not linearly, but more non-linearly, as a power function of how long the period is between substantial rain events capable of noticeably changing flow levels.
Posted by: Seina

Re: Streamflow Observations - 06/02/2012 14:37

Experts suggest link between coal mining and fragile lakes

Quote:
It is possible that we can interconnect aquifers that are not currently connected.
Posted by: Seina

Re: Streamflow Observations - 17/02/2012 13:21

Originally Posted By: -Cosmic- (naz)
I feel there is now an increased chance March-April 2010 river conditions being reached or exceeded (i.e. severely low flow levels). While there is every possibility this synoptic pattern could be broken within weeks or months, with each passing day without rain, the probability of a robust change in the patterns falls, not linearly, but more non-linearly, as a power function of how long the period is between substantial rain events capable of noticeably changing flow levels.

[Increasing chance] Continues to climb…

[NB: Based on recent analyses, this trend in reducing stream flow levels is dynamic, meaning it could change.]
Posted by: Seina

Re: Streamflow Observations - 29/02/2012 11:22

This system has been looking interesting (28th-29th) for some time. Initial forecasts appeared to indicate larger totals on the 25th-27th, however the atmospheric conditions were not particularly conducive to breaking the increasing chance of severely low flow levels. There appear to be some fine streams of rain through the Mount Lofty Ranges area in general at the moment, but time will tell whether this rain goes beyond mostly soil moisture.

At the current rain rate of about 2 mm/hr, it will likely take perhaps 5-6 days [possibly less, given this is a dynamic system] for rainfall to have a noticeable affect on run off. Some puddles and beginning to form, but I think 3-4 mm/hr or more might be more sufficient (over 2-3 days).

Edit (update):

Having said all that, this rain is very consistent. Rain rate now 3.7 mm/hr.
Posted by: Seina

Re: Streamflow Observations - 29/02/2012 17:52

Rain rate is not yet sufficient for significant change in runoff (stream flow).
Posted by: Seina

Re: Streamflow Observations - 04/03/2012 21:09

Now that we're officially in March and Autumn:

Taken 5.15 pm, 26th of February 2012, looking upstream:



Taken 5.20 pm, 26th of February 2012, Dry Landscape:



Taken 5.15 pm, 26th of February 2012, looking downstream:



Taken ~ 5.30 pm, 26th of February 2012, looking downstream:



…has not change much since.
Posted by: Seina

Re: Streamflow Observations - 07/03/2012 13:28

We now have a week or more with little or no probability of rain fall (BoM).
Posted by: DeclanJustin123

Re: Streamflow Observations - 07/03/2012 19:44

Hello! I am new in this forum too!I am a new member in this community. I am happy to be here. Thank you!
Posted by: Seina

Re: Streamflow Observations - 11/03/2012 12:24

System note: ~14th-17th March 2012 on Thursday, 8th March.
Posted by: Seina

Re: Streamflow Observations - 13/03/2012 17:43

Written Friday, March 09, 2012 (I think this is worth a mention), updates where indicated:

I believe, at this stage (9/3/2012), there is the possibility (GFS, maybe ACCESSG) for a significant low pressure system to form over Central South Australia circa 14th-16th March (a cut-off low, surrounded by high pressure to the south, low to the north [tropics]), dragging with it moisture from the Southern Ocean. Soil moisture may be up in the southeast [Australia], much drier in the southwest. Significant (+20 mm) falls may be possible in the Adelaide Hills [update (13/3/2012): latest GFS suggests up to 40-45 mm, 14th-15th]. I suspect there will be a change in the weather pattern in general (temperatures specifically, from low-to-mid 30s to low-to-mid 20s) in addition to a change to runoff and pressure (likely a substantial fall based latest GFS – 9th March [backed up 13/3/2012]). Update (13/3/2012): change in soil moisture 0-10 cm may be as much as 50% of current levels [for example: 50% of 0.2 is 0.1 => 0.2 + 0.1 = 0.3].

The reasons for drawing these conclusions are several-fold:
  • An extended dry period with little discernible change in river flow (most recent rain fall has evaporated or soaked into the soil – 24.7 mm in a 24-hour period, with patchy falls a few days after).
  • Bedrock formations becoming clearly exposed in the riverbed – suggests a higher evaporation rate.
  • Very dusty underfoot; top-soil may have lost some structure due to lack of rainfall/biological activity.
  • Insufficient evidence of continuation of river flow from groundwater sources, first noted on the 4th of February (at least a month ago).
  • Prevailing light/no winds – insufficient moisture advection.
  • Temperature (maxima and minima) remaining relatively steady for several days to weeks (the diurnal difference increasing).
  • A general absence of moisture in the local catchment system (temperature too high or low, humidity too low, pressure average).
  • A relatively moderate pressure for the said dry period – no significant deviation from observed mean conditions (pressure as at 11 am, 12th March 1013 hPa, currently ~1000 hPa, i.e. falling).

I am not going to guarantee that it will rain in the said period, but there appears to be a higher probability of rain falling during that period, at this point (13/3/2012).
Posted by: Seina

Re: Streamflow Observations - 17/03/2012 16:45

Mostly moderate rain ~ 6 pm to 8:40 pm (14th); Pressure down to 990, then up to 993 hPa ~ 8:40 pm; Temperature 17 C. Rainfall: 15.7 mm total.

Still not enough moisture in the catchment to see a noticeable change in surface runoff (apart for more of a green tinge to the paddocks).
Posted by: Seina

Re: Streamflow Observations - 20/03/2012 17:12

Written 18th March 2012:

Multiple events possible: Tuesday evening-night, frontal system; current forecasts temperature 30-31 C early Tuesday afternoon, 17-18 C through to 25th (next Saturday); 15-20 mm (estimate, at the moment). See ACCESS-R, -G, GFS! First front (short-wave) may clip (or jackknife) Fleurieu Peninsula Central Areas. Overnight lows now regularly 4-5 C. 16.6 mm to Friday night. Significant change pressure and specific humidity (18th and update 19th) – with reservations: 20-40 mm (moisture from current Tropical Cyclone Lua (18th)). Second front may be possible in the days after (3-5 mm). May also be a chance of thunderstorms (?) Tuesday night (update 19th).

Higher falls in the southeast: 20-40 mm (mean falls).

Question: is there a pattern shift this week?

[Note: Higher falls on the 14th to west and south-west Fleurieu.]

Yesterday (Monday 19th): Unchanged.
Today (Tuesday 20th): 17-18 C through to this time next week (unchanged). Pressure now ~ 991 (4.40 pm), was 1005, 2.40 pm 19th.

Time will tell smile .
Posted by: Seina

Re: Streamflow Observations - 23/03/2012 13:14

10 mm overnight Tuesday-Wednesday. Higher falls again to west and south-west (~ 15-22 mm, BoM). 2.7 mm from stream (?) showers yesterday overnight to 12 midday today. No significant affect on runoff (yet).
Posted by: Seina

Re: Streamflow Observations - 27/03/2012 19:45

Post: #862764 - 11-05-2010 03:48 PM:

Originally Posted By: -Cosmic- (naz)
Same Place as Peak Flow, Pre-Winter 2010

The distance from where the photos are taken to the river bed is about 5-7 metres vertically.

Pretty much sums up this situation in the riverbed today. Ponds/puddles fast disappearing.
Posted by: Seina

Re: Streamflow Observations - 02/04/2012 09:52

Special Note Written 1st April 2012: Observations

Possible spike in [specific] humidity circa 27th March. Trace on 30th (convective). Pressure may fall in coming days.

Today (2nd) could be interesting. Convective activity already evident.
Posted by: Seina

Re: Streamflow Observations - 02/04/2012 16:29

This is recently, Late March (24th) this year:



This is Early-to-Mid May (11th) 2010:

Posted by: Seina

Re: Streamflow Observations - 09/04/2012 13:44

9th April 2012: Surface-water drying out rapidly. Questioning potential causes. Not obvious confused .
Posted by: Seina

Re: Streamflow Observations - 15/04/2012 20:32

Originally Posted By: -Cosmic- (naz)
9th April 2012: Surface-water drying out rapidly. Questioning potential causes. Not obvious confused .

Highest recorded surface atmospheric pressure in the last week was around 1032 hPa (following a ferocious wind change on the 6th). This pressure was greater than or equal to only two other pressures (2-year period), in October last year, or April 2010. It clearly represents significant departure (change in conditions) from late January to the end of March, during which the pressure did not exceed 1020.

Indications are that it [pressure] may be the highest recorded pressure in the last two years, and is quite possibly contributing to low rainfall/streamflow.

What little rainfall there is, is soaking straight into soil – major sign of deficit in water availability! .

Not expecting any falls to impact on that deficit within at least a week. I have concerns we may be in for a prolonged period of frosts in the coming weeks, but I hope [if so] they are not too severe.

The most likely possibilities at the moment are that:

(a) We’re entering into a prolonged period of weekly frost conditions (~20/0 – 15/0), with intermittent ~25/5-20/5;
(b) Winter is approaching earlier than expected. Whether this means more regular or coherent pressure-troughs (intermittently accompanying high-pressure systems, a sign of significant rain) is open to question.

Streamflow is continuing on downward trend (getting quite dusty)… winds on the 6th were ferocious from the west and southwest. Debris strewn everywhere – massive change in wind speed (bending trees) synonymous with change in pressure and specific humidity (1032 on 11th). Initial wind change clearly visible mid-morning, after which probability of [any] rain fell.

Current conditions for runoff are concerning!
Posted by: Seina

Re: Streamflow Observations - 15/04/2012 20:40

Apologies with any timing of the above post, but I'm staying on topic.
Posted by: Seina

Re: Streamflow Observations - 16/04/2012 14:26

Where would others suggest I put information concerning “impending drought conditions without significant rainfall in the Adelaide Hills, April 2012” (without reference to climate change)…or could I start a new thread?
Posted by: DaveM

Re: Streamflow Observations - 16/04/2012 15:55

If it was intended as SA specific - then maybe the SA forum section. If you're thinking wider than just SA a new topic in General Weather may be the place. smile
Posted by: Surly Bond

Re: Streamflow Observations - 16/04/2012 18:34

Naz, I am mulling over a similar situation at my place. Very low humidity may lead to frosts.
You will have seen my graphs on recent anomalously low values of monthly Relative Humidity.

This month (April) has a low average morning Dew Point of 6.3 to date, and I expect it to average about 5.5 with all data in. That is about 3.5 below normal for this month. In terms of Relative Humidity, that will be about 77% instead of the usual 87%. I had such low RH values last July and in September 2009, but they are very rare. They don't occur in my earlier record except in in the peak of our last drought in October 2002.
In my data, even recent months with high rainfall values have also had low humidity values.
I wonder if this has happened at other stations.

About streamflow...
My local stream, Greenhatch Creek, with a catchment of 70 square kilometres, flows only a few times in a decade. Extreme rainfalls in November and February have left some ponds up to now. There must be flow under the bed.
There is no convenient point to observe surface flow.
Posted by: Seina

Re: Streamflow Observations - 16/04/2012 22:31

Originally Posted By: DaveM
If it was intended as SA specific - then maybe the SA forum section. If you're thinking wider than just SA a new topic in General Weather may be the place. smile

I think, under the assumption of localised conditions, it would have to be SA specific because the assumption of impending conditions is based observations within the Adelaide Hills, even though, as Surly has indicated, it could be more widespread. I don’t think this idea of “impending drought” can be attributed to one or two sole causes, and the hydrometeorology (in this case) is very dynamic, hence my no-climate change reference. Taking all into consideration, I would also like to see what others have to say from other regions/localities, so perhaps General Weather is a better place smile .
Posted by: Seina

Re: Streamflow Observations - 21/04/2012 13:42

Originally Posted By: Surly Bond
About streamflow...
My local stream, Greenhatch Creek, with a catchment of 70 square kilometres, flows only a few times in a decade. Extreme rainfalls in November and February have left some ponds up to now. There must be flow under the bed.
There is no convenient point to observe surface flow.

Sound like it’s ephemeral (flow based on rainfall only). I think our local river is meant to be perennial (flow all year round), but only in recent years (particularly the end of 2010 and now) has moderate-to-significantly low flow become more evident. It’s very dusty underfoot and the river has actually not been flowing (as in visible, non-groundwater surface flow) for weeks to a month or more. There was a period when groundwater “spring” contribution was evident, but it was intermittent at best. All that is left at the moment are some large 0.5-1 metre deep areas, the rest is dry, as in puddles I did not expect to dry up completely (although I can be certain they wouldn’t have) did. The river environment also provides much support and habitat to local fauna and flora, including (at one point earlier this year) small fish, wild ducks (quite common), rodents, ibis and probably some other things that live in the depths. So if one removes water from the equation, one removes a hell of a lot of natural activity.

I thought the puddles that dried up back in May 2010 probably wouldn’t dry up again for some time – the puddle are drying up (if they haven’t already), despite the green tinge in the pastures, a contradiction if one could call it that. Very dry!

Time will tell whether this next “rain event and showers” circa 21st-25th (this month) will come to anything. GFS seems to indicate maybe 10-15 mm over 2-3 days. From my own estimates I have 10-20 mm, which is right on the edge of the possibly significant falls (i.e. 3-4 mm per hour for 5 days), with 25 mm at the upper extremity. I also have to factor in (in my estimate) the humidity which goes up and down with the diurnal cycle like a yo-yo; it basically means every day there is a very remote chance of rain, just that the right conditions (other variables) are highly unlikely to be sufficient most of the time.
Posted by: Surly Bond

Re: Streamflow Observations - 21/04/2012 16:09

Certainly, Greenhatch Creek is "ephemeral", but I don't think that means "flow based on rainfall only".
As I mentioned, water appeared in the channel some time during our deluges of November and February. I had not noticed water for some years, even though there had been rainfall events. I surmise that the water table had been too low recently for even heavy rain to cause surface flow. Even in this ephemeral stream, surface flow requires a saturated catchment.
I notice that you are near a place called "Chain of Ponds". This is a recognized geomorphological term, but Google search is now swamped by commercial entries. You have to add "geomorphology" as a search term to by-pass the spam.
One page that gives the sense and significance of "chain-of-ponds" is here:
http://www.springerlink.com/content/t1730878358772n6/
Stream channels in SE Australia, in certain climate conditions, can lose the ability to form a channel, which is replaced by a chain of separate ponds. This landform was commonly observed by early explorers.
I doubt that research has yet revealed how it happens.
Posted by: Seina

Re: Streamflow Observations - 21/04/2012 18:03

Excuse the mistake I made earlier upon editing, it was 3-4 mm per day for 3-5 days, not 3-4 mm per hour smile .

Originally Posted By: Surly Bond
Certainly, Greenhatch Creek is "ephemeral", but I don't think that means "flow based on rainfall only".

By ephemeral, I meant flows intermittently, which can include artesian flow from groundwater; could have clarified a little better. By rainfall-only I meant that unless there are sources of water upstream, runoff from higher ground, whether above the surface or sub-surface, contributes to streamflow. But I don’t live in your area, and so am thankful to have input from on-the-ground from somewhere else.
Posted by: Seina

Re: Streamflow Observations - 23/04/2012 11:17

Originally Posted By: -Cosmic- (naz)
with 25 mm at the upper extremity.

Is now exceeded, approaching 30, last recording (~8.30 am) 26.3 mm.
Posted by: Seina

Re: Streamflow Observations - 25/04/2012 10:48

32.7 mm to 4.30 pm yesterday (21st-24th)...no significant changes to flow, not that the river is visibly flowing.
Posted by: Seina

Re: Streamflow Observations - 04/05/2012 17:16

The chance of flows being as low as they were in early-to-mid May 2010 (within the next week or two), has probably now diminished. However, 3 to 4 inches (~75 to 100 mm) over a few days to a week might be enough to have proper (mean?) flows again.

On another note, observations of rainfall over the last 2 years (relatively short period of time so far) suggest whether “breaking rains” occur may be affected by the capacity of the surface soil layer to retain moisture, and more importantly the connectivity of soil pores, which is affected by whether there is moisture or not, which can include condensation from frosts and high humidity (or fogs).
Posted by: Seina

Re: Streamflow Observations - 06/05/2012 12:50

At the moment, from my own observations, it seems there might be the possibility of significant rain on or around the 8th and 9th. Things look fairly changeable as well, but will wait and see smile .

As an aside, 10 small (5-10 cm diameter) ant nests (mounds) have been observed in a cluster in an approx. 5-m square area near the river.
Posted by: Seina

Re: Streamflow Observations - 09/05/2012 21:31

Originally Posted By: -Cosmic- (naz)
At the moment, from my own observations, it seems there might be the possibility of significant rain on or around the 8th and 9th. Things look fairly changeable as well, but will wait and see smile .

I guess not.
Posted by: Seina

Re: Streamflow Observations - 12/05/2012 20:06

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
At the moment, from my own observations, it seems there might be the possibility of significant rain on or around the 8th and 9th. Things look fairly changeable as well, but will wait and see smile .

I guess not.

Basically it seems like there might have been some other factor I did not take into account as to why there was little chance of rain during that period – the 8th to 9th. The estimate I made was based only on precipitable water and pressure. Perhaps specific or relative humidity were more significant!?
Posted by: Seina

Re: Streamflow Observations - 17/05/2012 11:11

Second sub-zero frost in as many days – possibility of major onset of rain in week’s time or so...
Posted by: DaveM

Re: Streamflow Observations - 17/05/2012 11:35

Do you think the stream has seeps into it or it relies only on surface drainage?
Posted by: Seina

Re: Streamflow Observations - 17/05/2012 11:40

Originally Posted By: DaveM
Do you think the stream has seeps into it or it relies only on surface drainage?

Not sure because it seems fairly dynamic, probably yes. Spring activity probably more certain (especially upstream).

I think we're on an alluvial plain.
Posted by: Surly Bond

Re: Streamflow Observations - 17/05/2012 18:10

Naz, may I suggest that, without learning a lot more about your landforms, you will be shooting in the dark.
The plain near the stream could be an erosional plain, not formed by a river, or it could be an alluvial plain, in which case it could be a flood-plain or a terrace. Floodplains are actively changed by channeled stream-flow or by over-bank flow in the present climate: terraces are too high to be affected. I am sure there is data on similar streams near you that you could use to assess what kind of a plain it is.
In Australia, floodplains are generally flooded in 2% of the years. In the old world it seems that floodplains are flooded almost once a year.
A technique for describing landforms to help to understand them is here.
http://books.google.com.au/books?printse...epage&q&f=false
Part of the technique is in this book sample, but you have to buy the book to get all of it, and you really have to think it through thoroughly. I recommend the Second edition.
A great tool for the work is a detailed topographical map. You can easily outline the alluvial land because it has exactly the same slope as the bed of the stream, and runs in the same direction. I am sure that maps at 1:25,000 scale exist, and probably maps at 1;10,000 or larger, with a 1 metre contour.
Best of luck.
Posted by: Seina

Re: Streamflow Observations - 19/05/2012 10:16

Originally Posted By: Surly Bond
Naz, may I suggest that, without learning a lot more about your landforms, you will be shooting in the dark.
The plain near the stream could be an erosional plain, not formed by a river, or it could be an alluvial plain, in which case it could be a flood-plain or a terrace. Floodplains are actively changed by channeled stream-flow or by over-bank flow in the present climate: terraces are too high to be affected. I am sure there is data on similar streams near you that you could use to assess what kind of a plain it is.
In Australia, floodplains are generally flooded in 2% of the years. In the old world it seems that floodplains are flooded almost once a year.
A technique for describing landforms to help to understand them is here.
http://books.google.com.au/books?printse...epage&q&f=false
Part of the technique is in this book sample, but you have to buy the book to get all of it, and you really have to think it through thoroughly. I recommend the Second edition.
A great tool for the work is a detailed topographical map. You can easily outline the alluvial land because it has exactly the same slope as the bed of the stream, and runs in the same direction. I am sure that maps at 1:25,000 scale exist, and probably maps at 1;10,000 or larger, with a 1 metre contour.
Best of luck.

Thank you for your insight and information, I will consider the material smile .
Posted by: Seina

Re: Streamflow Observations - 20/05/2012 13:33

Based on photos taken of the river on the 17th, breaking winter rains (or rains of any sort) would need to be substantial (say at least 20-30 mm or more over 2-3 days) to get it flowing properly again. For the water level to reach median conditions again – i.e. at least to the water mark seen on the side of the riverbank in places – would likely require many inches of rain, over an extended period of time. Causes of recent trends in river conditions are unknown (aside from periods of light to moderate intermittent rain or showers), but low-to-very-low minimums may be playing a part – last night 2 degrees. An increase in the minimums brought on by an increase in precipitable water and humidity might also be worth consideration.
Posted by: Seina

Re: Streamflow Observations - 22/05/2012 14:24

See here for latest on rainfall prospects.
Posted by: Seina

Re: Streamflow Observations - 23/05/2012 12:04

For more information on conditions of the last couple of months, see post #1099642 - 15-04-2012 08:32 PM, possibility "a".
Posted by: Seina

Re: Streamflow Observations - 24/05/2012 11:49

Originally Posted By: -Cosmic- (naz)
Based on photos taken of the river on the 17th, breaking winter rains (or rains of any sort) would need to be substantial (say at least 20-30 mm or more over 2-3 days) to get it flowing properly again.

30 mm in the 20 hours 15 mins to 11.15 am this morning. River is flowing upstream. Water level downstream has probably risen 75 cm.
Posted by: Seina

Re: Streamflow Observations - 27/05/2012 17:03

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Based on photos taken of the river on the 17th, breaking winter rains (or rains of any sort) would need to be substantial (say at least 20-30 mm or more over 2-3 days) to get it flowing properly again.

30 mm in the 20 hours 15 mins to 11.15 am this morning. River is flowing upstream. Water level downstream has probably risen 75 cm.

River level is steady at 75 cm to 1 metre rise (and visibly flowing) – 64.6 mm in the 5 days 10 hours to 10 am today.

Note: temperature was 6 degrees at 4 pm on Thursday the 24th. The following overnight low was just 1 degree. The local (sfc.) pressure dropped to 1003 hPa on the 23rd.

This event had been a possibility for at least a week, but not until the last few days before the onset did the confidence appear increase sufficiently. For this reason I was not going to over- or under-dramatise how things would pan out (or how much of an impact rainfall would have on run-off), and decided to wait and see what happened for a change smile .
Posted by: Seina

Re: Streamflow Observations - 30/05/2012 14:58

http://www.bom.gov.au/climate/ahead/rain_ahead.shtml?link=1

Not looking that flash for Central SA for the coming winter…nor Southwest WA frown .
Posted by: Seina

Re: Streamflow Observations - 02/06/2012 13:49

Possibility of significant change in soil moisture, run-off circa 4th June.
Posted by: Seina

Re: Streamflow Observations - 03/06/2012 20:51

Originally Posted By: -Cosmic- (naz)
Possibility of significant change in soil moisture, run-off circa 4th June.

Probability of significant change in soil moisture, run-off.

BoM - 95% chance of 10 to 20 mm tomorrow (I suspect more atm); latest forecast.

8 pm stats: 1014 hPa (sfc.), 2 deg C, 87% RH.
Posted by: Seina

Re: Streamflow Observations - 04/06/2012 23:00

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Possibility of significant change in soil moisture, run-off circa 4th June.

Probability of significant change in soil moisture, run-off.

BoM - 95% chance of 10 to 20 mm tomorrow (I suspect more atm); latest forecast.

8 pm stats: 1014 hPa (sfc.), 2 deg C, 87% RH.

Current rain rate approx. 3.4 per hour. 30.2 mm system to date (3rd into 4th). River up probably another 25 to 50 cm. Higher gaugings to the east and south.
Posted by: Seina

Re: Streamflow Observations - 05/06/2012 19:05

Biggest estimated increase in soil moisture since 24.7 mm on the 29th of February, when it rose from ~0.185 to 0.213 (that is the fraction of soil containing water). Soil moisture (est.) was ~0.202 on the 19th (of May), rose to ~0.229 by the 26th, and is now around 0.226 following 33.9 mm over the last 3 days (most falling overnight on the 3rd-4th and 4th-5th). River obs. indicate streamflow peaked sometime overnight close to midnight (4th-5th). Vegetation and other grasses along the riverbed show clear signs (contours) of water travelling down the river. The water is also quite murky and there is some debris strewn in patches which may indicate just how high it got (perhaps another 10-15 cm).

While this has not been a major change in runoff (e.g. like September 2010), there has been enough rain over a long-enough period of time to replenish surface and sub-surface water significantly.

The average winter maxima and minima June 1st to date are 14.6 degrees and 4.2 degrees respectively, with -1 recorded on the 31st (May).
Posted by: Seina

Re: Streamflow Observations - 08/06/2012 12:29

Note 24-hr falls to 9 am 5th of June 2012
Posted by: Seina

Re: Streamflow Observations - 11/06/2012 11:32

Post: #1099642 – 15-4-2012:

Originally Posted By: -Cosmic- (naz)
(a) We’re entering into a prolonged period of weekly frost conditions (~20/0 – 15/0), with intermittent ~25/5-20/5;

2012: Sub-zero frost or near-frost conditions – Overnight Lows May-June to date.

*Indicates definite frost.

15th-16th-May: -4.*
16th-17th-May: -1.
20th-21st-May: -3.*
31st-May-1st-June: -1.
7th-8th-June: -2.*
9th-10th-June: -2.*
10th-11th-June: -6.*

May be an indicator of lower rainfall.
Posted by: Seina

Re: Streamflow Observations - 11/06/2012 11:53

Originally Posted By: -Cosmic- (naz)
May be an indicator of lower rainfall.

Or alternatively freezing rain.
Posted by: Seina

Re: Streamflow Observations - 13/06/2012 19:16

Possible significant/major rainfall event starting 13th/14th...noted on forecasts 4th.
Posted by: Seina

Re: Streamflow Observations - 15/06/2012 23:29

Originally Posted By: -Cosmic- (naz)
Possible significant/major rainfall event starting 13th/14th...noted on forecasts 4th.

11.1 mm to approx. 6.45 pm yesterday; moderate rainfalls, probably barely significant – enough to contribute to soil moisture a bit.
Posted by: Seina

Re: Streamflow Observations - 19/06/2012 17:35

Written 18th June 2012:

It seems likely there will some rain as of Thursday (update 19th: Wednesday-Thursday) the 21st coming through from a frontal system in the southern ocean. At a guess, I’d say maybe 10-20 mm over a 12-to-24-hour period from Thursday into Friday at the moment; based on that an estimate of soil water content might increase from its current 0.219 to between 0.221 and 0.226 as a fraction of total volume, and streamflow up to 0.0034 (as an index) from the current 0.0013, which is about 2.6 times the magnitude.

2.6 times the magnitude of current flows, given the last substantial rains raised the river level by up to 125-150 cm from relatively low levels prior to the 20th of May, would mean a rise in the order of another 2 to 2.5 metres (which sounds a bit exaggerated, maybe a metre or two, but who knows – we might get more rain). A rise of 2 to 2.5 metres would have the local flood plain close to or actually flooding. This doesn’t take into account a lack of concrete knowledge of underground systems but is basically based on an analysis of rainfall and temperature patterns, which may partially factor in evaporation and transpiration through temperature-dependence.

From the recent forecasts made available by weatherzone (today (18th), 12 noon), 20-40 mm is suggested for parts of north-eastern Victoria, with snow and sub-zero temperature forecast for the mountains to the east from about the 21st onwards for a few days. That may mean the penetration for the frontal system of this coming event will be much further north, or alternatively that it will peak in that region and clip (update 19th: most likely clip) the Adelaide Hills. A lot of rain is also forecast for the south-east as of about Wednesday, with 5-10 and 10-20 mm a common feature from then onwards for several days in Mt. Gambier.
Posted by: Seina

Re: Streamflow Observations - 21/06/2012 12:29

Originally Posted By: -Cosmic- (naz)
At a guess, I’d say maybe 10-20 mm over a 12-to-24-hour period

based on that an estimate of soil water content might increase from its current 0.219 to between 0.221 and 0.226 as a fraction of total volume, and streamflow up to 0.0034 (as an index) from the current 0.0013, which is about 2.6 times the magnitude.

30 mm to 10 am – estimated soil water content now 0.23.
The river another ~25 cm higher; Index ~0.005.

The figures might seem accurate, but the 25 cm rise is not 2.6 times the magnitude of 125-150 cm. It’s between 20 and 17% of the magnitude, which means the relationship may be more logarithmic than linear with the overnight rain rate.

The response of the river system to the breaking rains, and now these, is a little contrasting and perhaps puzzling. Over the period 22nd to 29th (May) we received about 67 mm, yet the index rose from 0.00032 to 0.00214 (0.001 difference), whereas with 30 mm in 17 hours is only 0.0013 to 0.005, or 0.0037 difference. This seems to indicate the river level is steady, in the sense that it’s neither rising nor fall dramatically.

A rough re-calculation based on these obs suggests to get a metre rise from levels a day ago would require at least 155 mm in the same period.

NB: Figures (estimates) to be taken as a rough guide only.

Also: http://www.bom.gov.au/cgi-bin/wrap_fwo.pl?IDS20368.html
Posted by: Seina

Re: Streamflow Observations - 24/06/2012 12:18

Written 4.30 pm, 23rd.

After 61 mm over a period of 71 hours (with a few brief sunny periods after 12.30 pm and more after 3.30 pm, 22nd), the Upper Onkaparinga was beginning to resemble a raging torrent. While the river height had not changed much, its visible breadth had.

River beginning to peak:



(Shorter footage uploaded due to the size of longer video)

The ground was saturated. The rain at times in the 24-hours to 3 pm, 22nd, had been enough that when the sun did poke through the clouds, the surface water (still running off the paddocks from the last intense event) was a vast sight (of adjoining puddles).

The rain-soaked surroundings:





The river peaked moderately sometime between 3.30 and 4.30 pm, Friday.
Posted by: Seina

Re: Streamflow Observations - 30/06/2012 15:14

Almost 140 mm for the month (pending the rest of the day)...the most since August 2010. Soil moisture estimates approaching the 0.25 threshold surpassed in that year (was 0.233 yesterday).
Posted by: Seina

Re: Streamflow Observations - 30/06/2012 17:40

Post #930498 - 16-01-2011 09:41 PM:

Originally Posted By: -Cosmic- (naz)
Atm, given what's been happening in other states recently, I figured it might be worth keeping an eye on these things for a while...however I can't garauntee this thread continuing indefinitely without some kind of feedback/questions, etc smile .

The above still stands…I’m considering only mentioning extremes events/periods, if that, if no one else gives some sort of an indication or interest that they want information continuing in this thread. This thread is not just about my observations, anyone can post theirs in here too.
Posted by: Seina

Re: Streamflow Observations - 08/07/2012 21:01

Statistical note:

Some Frost/med-to-low humidity statistics (high-humidity rain) + corrections:

Post: #1099642 – 15-4-2012:

Originally Posted By: -Cosmic- (naz)
(a) We’re entering into a prolonged period of weekly frost conditions (~20/0 – 15/0), with intermittent ~25/5-20/5;

Revision taking into account recent obs-to-date:
~ (20/-7) to (15/-7) and (perhaps with rain) ~ (20/5) to (10/5)… (Winter)

2012: Sub-zero frost or near-frost conditions – Overnight Lows May-July to-date.

Bold indicates increasing severity of frosts.
*Indicates definite frost.

15th-16th-May: -4/~41%.*
16th-17th-May: -1/~36%.
20th-21st-May: -3/~58%.*
30th-31st-May: -1/~57%.
7th-8th-June: -2/~44%.*
9th-10th-June: -2/~34%.*
10th-11th-June: -6/~46%.*
…Major rainfall period… (20th-30th June)
22nd-23rd-June: -2/~83% (Rain)
26th-27th-June: -2/~45% (Little Rain)
30th-June-1st-July: -2/~67%.
2nd-3rd-July: -3/~51%.
5th-6th-July: -5/~33%.*
6th-7th-July: -5/~36%.*
7th-8th-July: -2/~40%.

I believe this important enough for a preliminary note: -5 degrees overnight (6th-7th) with a substantial frost. No substantial rain since the beginning of the month (river is flowing steadily), and the humidity has been falling in a corresponding fashion, down to 20-40% from around 80-90% between 20th and 30th June.

Note: for a period of 11 days starting 12th June (during the onset rain events) the minimum didn’t drop below zero.
Posted by: Seina

Re: Streamflow Observations - 13/07/2012 17:45

Originally Posted By: -Cosmic- (naz)
Note: for a period of 11 days starting 12th June (during the onset rain events) the minimum didn’t drop below zero.

Possible onset of period No. 2...starting the 9th just gone.

Visible change in flow already evident. Possible major flux in streamflow coming up within the next 7 days.
Posted by: Seina

Re: Streamflow Observations - 19/07/2012 13:41

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Note: for a period of 11 days starting 12th June (during the onset rain events) the minimum didn’t drop below zero.

Possible onset of period No. 2...starting the 9th just gone.

Visible change in flow already evident. Possible major flux in streamflow coming up within the next 7 days.

Bold Added.

Correlation perhaps, but not so much causation.
Posted by: Seina

Re: Streamflow Observations - 22/07/2012 21:56

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Note: for a period of 11 days starting 12th June (during the onset rain events) the minimum didn’t drop below zero.

Possible onset of period No. 2...starting the 9th just gone.

Visible change in flow already evident. Possible major flux in streamflow coming up within the next 7 days.

Bold Added.

Correlation perhaps, but not so much causation.

As a note of benefit (at the moment for rainfall, possibly):
  • Blocking high-pressure system needs to start moving (east) – pressure needs to fall.
  • Overnight lows need to rise more than they have (closer to 8-9 deg C rather than 0-8).
  • Relative humidity (in diurnal pattern) needs to start increasing.
Posted by: Seina

Re: Streamflow Observations - 24/07/2012 20:54

Written earlier today:

About 2 weeks ago a gradual drop in pressure was evident on the shorter-term GFS projections, and to a lesser extent the longer-term. The pressure was forecast to reach a low point sometime between the 25th and 27th of this month (probably closer to the 25th). In the period since the trend appears to have barely shifted, with the magnitude of what is (projected) to come being more the question than the likelihood of (rain/showers) falling sometime in that period.

The streamflow (runoff) forecast has been a bit all over the place in that sense, with the most recent run showing a change (in kilograms per squared metre) of up to maybe 20-30 x the current magnitude (not order of magnitude)… it seems very interesting, despite the idea the forecast could still change with what time is left (to reach the low point) or at the very last moment (hour or two).

I’m going to throw up for interpretation what others might think of the period to about 5th of August. I have noted that several things could happening in that period, a mix of possible conditions (or extremes).

For anyone who is interested in the implications of the could’s for that period, I would welcome your input.

The forecasts source: http://nomad3.ncep.noaa.gov/ncep_data/
Posted by: Seina

Re: Streamflow Observations - 26/07/2012 12:08

19.3 mm overnight with visible and audible change in flow. Possibly more to come this afternoon/evening.
Posted by: Seina

Re: Streamflow Observations - 28/07/2012 17:00

I believe somewhere, sometime ago I may have mentioned 150 mm might be necessary for a significant change (in run-off) over 2-3 days out to maybe a week. I think that could be more accurate than first realised (42.8 mm to midday, system total, moderate change in flow)…and this might be saying something as well.
Posted by: Seina

Re: Streamflow Observations - 09/08/2012 12:37

13.8 mm 9 am yesterday to midday today.

The change in flow of the local river is a bit interesting; is 13.8 mm enough to cause it? It seems there could be some sort of sub-surface or groundwater contribution, maybe upwelling. I don’t know this for sure, but I’m a little curious about the flow rate compared to within the last day. The flow is quite audible, even from 50-100 metres away.
Posted by: Seina

Re: Streamflow Observations - 16/08/2012 11:46

14.7 mm over 3 days, most falling to 9 am this morning.

Possible significant change in runoff pending smile (over next 2-3 days).
Posted by: Seina

Re: Streamflow Observations - 16/08/2012 18:21

S''t, dramatic change in flow eek ! Over 30 mm system total (unchecked, probably higher).
Posted by: Seina

Re: Streamflow Observations - 16/08/2012 20:12

Broken/breaking its banks. Low-lying flooding.
Posted by: teckert

Re: Streamflow Observations - 16/08/2012 20:13

http://www.bom.gov.au/cgi-bin/wrap_fwo.pl?IDS20364.html
flood warning out
Posted by: Seina

Re: Streamflow Observations - 16/08/2012 20:16

Originally Posted By: teckert

Thanks smile ... needed that (flooding issues/concerns).
Posted by: Seina

Re: Streamflow Observations - 18/08/2012 17:38

64.5 mm to 4.15 pm today since the 13th.
Posted by: Seina

Re: Streamflow Observations - 21/08/2012 20:16

Written yesterday:
Vigorous Cold Front/Low Pressure System…No. 1 (16/08/2012)
(Some photos may show poor quality due to time of day/conditions)

Approx. 5:15 pm, early on:







Approx. 6:05 pm, Evening:





Approx. 9:58 pm:



Approx. 12:15 pm, 20th (the aftermath):



In short, after the river water level rose moderately to 5 pm on the 16th, it only (apparently) took another 19 mm over 1.5 hours for the river to break or begin breaking its banks – rising another 2-3 metres. The volume of water seemed to pass a threshold for flow response (meaning the response was very rapid). My thinking is there would have been even more rain further upstream towards Lobethal, which seems possible given the higher totals seen on the Bureau’s website for that period.

This seems to imply there is sufficient moisture in the catchment system to bring the river to flood, and that there are thresholds between critical periods of hours, days, weeks and months of increasing or decreasing soil or sub-surface moisture. How much moisture is in the system at any given time is still likely important, and critical to determining when a threshold is reached, however, of more interest is how this moisture contributes to the flow response.

This may also be evidence of an idea (untested hypothesis) about antecedent soil moisture conditions which can lead to either droughts or flooding rains smile … but for now GFS is indicating the possibility of additional follow-up rains (another significant-to-major event) this week (Wednesday-Thursday), first noted as possible on the 17th.
Posted by: Seina

Re: Streamflow Observations - 22/08/2012 14:39

Sfc. Pressure ~996 hPa @ 2pm.
Posted by: Seina

Re: Streamflow Observations - 23/08/2012 09:42

Originally Posted By: -Cosmic- (naz)
… but for now GFS is indicating the possibility of additional follow-up rains (another significant-to-major event) this week (Wednesday-Thursday), first noted as possible on the 17th.

Rainfall totals are insufficient to act significantly on runoff at the moment. Significant change in stream flow remains possible.
Posted by: Seina

Re: Streamflow Observations - 28/08/2012 21:08

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
… but for now GFS is indicating the possibility of additional follow-up rains (another significant-to-major event) this week (Wednesday-Thursday), first noted as possible on the 17th.

Rainfall totals are insufficient to act significantly on runoff at the moment. Significant change in stream flow remains possible.

Possibility ended 24th August.

-1 degrees C noted 26th-27th.

-------------------------------------------------------------

In my view, analysis of recent synoptic patterns/frontal/low activity suggests a change/shift in the pattern, possibly to wetter conditions.

--------------------------------------------------------------
For information only:

Written 23rd August 2012:
Development of Zonal Pattern, Several Fronts/Lows, Winter-Spring 2012!?

This is my opinion based on recent observations.

Noted: low central pressure in Bight – 964 hPa, 4 am AEST 23rd August 2012 (Bureau’s website).

In the thread “Spring/Summer 2012-13: Predictions, Observations and General Discussion” I mentioned in post #1117896 - 03/08/2012 15:33 that I thought the Southern Ocean weather/climate pattern was beginning to show signs of becoming more zonal (pressure gradient more latitudinal), in particular (not mentioned) across the Indian Ocean and Central Australia. The implication further to this is that it has/is becoming more conducive to frontal/low activity. This may also be supported by the passage of three systems which have crossed the (Southeastern) region since the 3rd, bringing moderate to significant falls (the latter two at least 30 mm in the Adelaide Hills, BoM) – peaking on the 8th, 16th and 23rd respectively.

On the Bureau’s MSLP run – 12 UTC 22nd August 2012:

The evident change from apparently meridional to zonal pattern appears to be consistent with the (long wave) Southern Ocean hemispheric pattern, in which the low pressure belt (south of about 30 degrees, BoM) in the Southern Ocean rotates incrementally (zonal-to-meridional) every so often. Although several lows appear in the Southern Ocean at present, it is clear that in the Pacific high-pressure dominates over low-pressure, or presents more longitudinal gradients, the opposite being the true nearer the Indian Ocean. The significant zonally situated high-pressure system is also evident in the Indian Ocean nearer the equator. In the case of the observed (zonal) change this (rotational period) may be 1-3 months, or a season.

Update 12 UTC 24th August 2012 (see Bureau’s website):

The latitudinal pressure gradient of high-pressure cells has now shifted somewhat from the Indian Ocean to extend into South Australia, and consists of six cells with central pressures (west-to-east) of 1021, 1021, 1024, 1024, 1024 and 1023 hPa respectively. I believe there may be further possibility, given this feature, of more rain in the coming week (or two) which could increase soil moisture (if not streamflow) once again. Further activity may follow (into early spring).

Update 28th – 06 UTC 27th August 2012 Synoptic Map (see Bureau’s website):

On this particular run I have noted a low-pressure system with a central pressure of 930 hPa nearing the south-western coast of South America. While the high-pressure feature extending from the Indian Ocean into Western Australia is less apparent, its effects are noteworthy with both the Southeastern and Western areas receiving up to 50 mm in places in the week ending today, and over 100 mm in the month-to-date (BoM).

While there continues to be the high-pressure feature to the north and east (possibly a blocking high) of the Southern regions I think this [higher probability of consecutive fronts/lows] may continue.

This appears to be a significant contrast to the blocking high-pressure systems of 2006 (from memory) – in 2006 Winter rains did not properly eventuate, in that case situated more centrally rather in the east. The last major flood events occurred in 1996.

The first significant probability of rainfall (in my view) may be sometime between the 29th and 31st of August. The second likelihood (again, in my view) could be sometime between the 3rd and 5th of September, at this stage.

See the Bureau’s latest forecast details for more information.
Posted by: Seina

Re: Streamflow Observations - 09/09/2012 20:29

Written (Wednesday) 5th September 2012:

Originally Posted By: -Cosmic- (naz)
The first significant probability of rainfall (in my view) may be sometime between the 29th and 31st of August. The second likelihood (again, in my view) could be sometime between the 3rd and 5th of September, at this stage.

See the Bureau’s latest forecast details for more information.

The surface pressure dropped from around 1012 hPa on the 3rd to 993 hPa on the 5th (last hour or two from 3.30 pm). Humidity was 23% last night [Tuesday] around 8.45 pm. Winds yesterday [Tuesday] were consistently strong to gale force with very strong gusts, possibly enough to make walking difficult [see Bureau’s observations for Tuesday]. The forecast period start day/time shifted by perhaps 1-2 days forward (from the 3rd), while it could be extended another couple (may be today (5th) till the 7th or 8th sometime). The general forecast though (particularly from the Bureau) appears to be consistent: moderate-to-heavy falls today (Wednesday) into tomorrow (update: now probably Friday as well), 5-15 mm each 24-36 hour period, possibly 20-30 tops with the odd heavy shower/thunderstorm (more tomorrow – Thursday). No major change in flow is expected as yet, but that probably also depends on how the local catchment responds to increasing surface/atmospheric moisture levels. Rainfall has be increasing over the last several hours (Wednesday). Perhaps one thing in favour of more rain is the humidity increasing by about 25% in 6 hours (from the low 60s at approx. 3.30 pm).

Modifications indicated by [].

Written (Thursday) 6th September 2012:

25.9 mm in the 42.5 hours to 6.30 pm this evening – the river is beginning to respond more noticeably (8 to 10 pm). Passing moderate-to-heavy showers at present. Possible thunderstorms/hail noted on Bureau’s 4.10 pm forecast for early tomorrow.

Chance of rain for the rest of the day was said to be 100%.

Hail confirmed 10.30 pm.

Written (Friday) 7th September 2012:

34.3 mm in the 57 hours to 9 am this morning + hail and gale force winds (and debris). *[Moderate change in flow apparent]
[Debris also remains marking the water level from the previous minor flood event.]

* Added (Saturday) 8th September 2012.

Written Today (Sunday) 9th September 2012:

Possibility insect behavioural observations indicative of something coming this Spring. Too early (?) to tell, but noted.

River flow (including further downstream) appears to be healthy.
Posted by: Seina

Re: Streamflow Observations - 22/09/2012 12:16

My views based on observations:

Developing an Understanding of the Earth’s Climate System:

Post #1114324 - 12-07-2012 11:45 AM

Originally Posted By: -Cosmic- (naz)
I have some ideas which overlap with this thread, but aim to be posting them in the thread “Streamflow Observations” in the General Weather Section due to their specific, regional nature (if anyone is interested smile ).

Longer-term observations suggest streamflow is gradually increasing [regionally], and that this increase may be linked to certain atmospheric conditions.

Analyses suggest a direct correlation with physical justification between weather variable(s) and soil moisture estimates...possibly to the extent of statistical significance, meaning some variable(s) could be used to predict or project soil moisture estimates in the near future within this region.

-------------------------------------------------

Streamflow remains healthy and is gradually receding, possibly implying enough moisture is present in the soil and air above (Precipitable Water) to maintain flows above a threshold. Recent estimates seem to indicate soil moisture also remains above the 20% fractional content of soil volume.

It is somewhat interesting that 0 deg C was recorded overnight 10th-11th and 17th-18th, possibly implying humidity low enough for an impending change or changes (in weather conditions) in the near future (days to a week from said dates).
Posted by: Seina

Re: Streamflow Observations - 25/09/2012 18:38

Originally Posted By: -Cosmic- (naz)
It is somewhat interesting that 0 deg C was recorded overnight 10th-11th [No. 1] and 17th-18th [No. 2], possibly implying humidity low enough for an impending change or changes (in weather conditions) in the near future (days to a week from said dates).

[] Added.
No. 3 zero degrees (23rd-24th).
No. 4 minus 2 degrees just gone (24th-25th).
Possibly something in the wind (2-3 days).

“Pressure starts falling (2-3 days out); increasing sporadic wind gusts; streamflow is falling;”
Posted by: Seina

Re: Streamflow Observations - 26/09/2012 18:12

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
It is somewhat interesting that 0 deg C was recorded overnight 10th-11th [No. 1] and 17th-18th [No. 2], possibly implying humidity low enough for an impending change or changes (in weather conditions) in the near future (days to a week from said dates).

[] Added.
No. 3 zero degrees (23rd-24th).
No. 4 minus 2 degrees just gone (24th-25th).
Possibly something in the wind (2-3 days).

“Pressure starts falling (2-3 days out); increasing sporadic wind gusts; streamflow is falling;”

5.30 pm:

Relative humidity now around 25%, [sfc] pressure having dropped from 1009 to 997 hPa in ~24 hours. Windy this morning, quite calm now.


Sitting on/near a trough line by the looks of the latest mean sea level pressure analysis from the BoM.
Posted by: Seina

Re: Streamflow Observations - 27/09/2012 18:55

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
It is somewhat interesting that 0 deg C was recorded overnight 10th-11th [No. 1] and 17th-18th [No. 2], possibly implying humidity low enough for an impending change or changes (in weather conditions) in the near future (days to a week from said dates).

[] Added.
No. 3 zero degrees (23rd-24th).
No. 4 minus 2 degrees just gone (24th-25th).
Possibly something in the wind (2-3 days).

“Pressure starts falling (2-3 days out); increasing sporadic wind gusts; streamflow is falling;”

5.30 pm:

Relative humidity now around 25%, [sfc] pressure having dropped from 1009 to 997 hPa in ~24 hours. Windy this morning, quite calm now.

6 pm:

Relative humidity remained around 30% mid-afternoon and is now roughly another 10% higher (was briefly around 50% this morning, possibly associated with the trough mentioned earlier). Sfc. Pressure down to 991-992 hPa.

Originally Posted By: -Cosmic- (naz)
Written Today (Sunday) 9th September 2012:

Possibility insect behavioural observations indicative of something coming this Spring. Too early (?) to tell, but noted.

Insects as in ants (flying ants) were also visible in at least three locations along the river today. Again, it’s difficult to tell why, but the surface pressure has now dropped significantly from recent values.

Today’s max reached 30 degrees…the way the pressure is going, it might drop below 990.

Will wait and see smile .
Posted by: Seina

Re: Streamflow Observations - 30/09/2012 11:18

21 days since the last moderate rainfall event (6th September)…15.7 mm to around 10 am this morning, system total. Flow response was minimal, but it was interesting to see observations unfold regardless smile .
Posted by: Seina

Re: Streamflow Observations - 30/09/2012 17:03

Originally Posted By: -Cosmic- (naz)
Flow response was minimal, but it was interesting to see observations unfold regardless smile .

Correction: discernible (visual and audible) change in flow apparent early afternoon, reasons unknown. Pressure has risen from 995 to 1022 in 2 days.
Posted by: Seina

Re: Streamflow Observations - 01/10/2012 16:39

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Flow response was minimal, but it was interesting to see observations unfold regardless smile .

Correction: discernible (visual and audible) change in flow apparent early afternoon, reasons unknown. Pressure has risen from 995 to 1022 in 2 days.

The surface pressure (today) has peaked 38 hPa above the pressure on the morning of the 28th (~992). It is now around 1026. Streamflow is showing no signs of abating in the last 12-24 hours…in fact, if anything it appears to be increasing. And again, for reasons unknown.
Posted by: Seina

Re: Streamflow Observations - 05/10/2012 14:51

Flow steadied in the last 4 days, a little lower. Temperature rose significantly in the same time, somewhat cooler today. 30, 30 and 29 degrees respectively over the last three days. Humidity plummeted to around 19%, 3.30 pm yesterday, currently back another 30 % higher.

Possible rainfall event(s) (GFS) noted mid-October.
Posted by: Seina

Re: Streamflow Observations - 06/10/2012 12:04

Written late yesterday:

Originally Posted By: -Cosmic- (naz)
Humidity plummeted to around 19%, 3.30 pm yesterday, currently back another 30 % higher.

Just over 60%; pressure adjusted roughly to mean sea-level (PRMSL) now about 1015 hPa @ ~ 5 pm. Temperature 13 degrees C @ ~ 5 pm, conditions become much more conducive to rain; estimated precipitable water increasing towards 20 mm.

Update:
Humidity currently 57% @ 11.30 am, PRMSL still around 1015 hPa. Temperature around 15 degrees. Estimated precipitable now in excess of 20. Conditions becoming very conducive to rainfall; 0.7 mm overnight, with lightning.
Posted by: Seina

Re: Streamflow Observations - 06/10/2012 20:17

Originally Posted By: -Cosmic- (naz)
Written late yesterday:

Originally Posted By: -Cosmic- (naz)
Humidity plummeted to around 19%, 3.30 pm yesterday, currently back another 30 % higher.

Just over 60%; pressure adjusted roughly to mean sea-level (PRMSL) now about 1015 hPa @ ~ 5 pm. Temperature 13 degrees C @ ~ 5 pm, conditions become much more conducive to rain; estimated precipitable water increasing towards 20 mm.

Update:
Humidity currently 57% @ 11.30 am, PRMSL still around 1015 hPa. Temperature around 15 degrees. Estimated precipitable now in excess of 20. Conditions becoming very conducive to rainfall; 0.7 mm overnight, with lightning.

Conditions have been in sufficient for facilitating further development.
Posted by: Seina

Re: Streamflow Observations - 07/10/2012 14:15

To clarify (from memory): BoM forecast 0 to 4 mm for the 6th, 0.9 mm fell.
Posted by: Seina

Re: Streamflow Observations - 12/10/2012 11:22

Recent falls suggest this area of the Onkaparinga Catchment is a good 25-30 mm/day away from a noticeable response to rainfall.
Posted by: Seina

Re: Streamflow Observations - 20/10/2012 13:11

Temperature observations from the BoM found here suggest an overnight low of zero recorded 16th-17th (Oct 2012) was not a faulty reading smile . The correspondingly low humidity of 36% recorded the following day appears to support drawing this conclusion. This may not mean there are significant falls on the way, but it does suggest a change in pattern/humidity is possible. The last falls – which were moderate – fell from the 10th to the 12th; 8 days ago.

Streamflow has been gradually falling since then.
Some stats (graphs):

Rainfall, Streamflow Estimates to the 17th since 1-1-2010.
Estimated Streamflow and Soil Moisture for Comparison (Same Period).
Posted by: Seina

Re: Streamflow Observations - 25/10/2012 14:22

Supplementary Note:

Originally Posted By: -Cosmic- (naz)
Temperature observations from the BoM found here suggest an overnight low of zero recorded 16th-17th (Oct 2012) was not a faulty reading smile . The correspondingly low humidity of 36% recorded the following day appears to support drawing this conclusion. This may not mean there are significant falls on the way, but it does suggest a change in pattern/humidity is possible.

I think the change in humidity just went through in the last 24 hours.
Posted by: Seina

Re: Streamflow Observations - 04/11/2012 14:36

The first significant change in humidity in a while (25th Oct) did not last.

Indications (according to GFS and ACCESS-R) are that precipitable water is going to increase rapidly and substantially in the next 24-48 hours, with possible falls up to ~20-30 mm (BoM) and possibly higher (maybe 45-60 mm GFS).

Will see if we get that much rain, but whether it translates into an order magnitude streamflow response is another matter. If we do get what’s forecast, and the local river does respond in a big way, it may mark the start of a shift in patterns of day-time humidity not seen since about June.
Posted by: Seina

Re: Streamflow Observations - 05/11/2012 22:12

Precipitable water (in mm) has increased sharply in the last 12-24 hours or so (GFS up to something like 35-40 mm, maybe higher).

(Sfc) Pressure has remained sustained @ 992-994 hPa (~1003-1005 hPa MSLP) for several hours to 2-3 pm, with some rather nasty wind gusts. Was 990 hPa (~1002 hPa MSLP) ~ 5 pm, increasing the probability of significant falls (and with it significant change in runoff).

Update Note: Latest GFS forecast has just a little worry about it (for next few hours or so).
Posted by: Seina

Re: Streamflow Observations - 06/11/2012 16:06

Originally Posted By: -Cosmic- (naz)
Update Note: Latest GFS forecast has just a little worry about it (for next few hours or so).

Concerns (based on likelihood of the forecast about those hours mentioned above) were without warrant [and probably unrealistic]. 3.5 mm to 9 am. The dry-spell of days without a significant change in runoff continues...
Posted by: Seina

Re: Streamflow Observations - 22/11/2012 12:32

Potentially something in the air...fair way out, but interesting. See 28-day Weatherzone Forecast.
Posted by: Seina

Re: Streamflow Observations - 22/11/2012 14:41

Originally Posted By: -Cosmic- (naz)
Potentially something in the air...fair way out, but interesting. See 28-day Weatherzone Forecast.

A possible more in-depth explanation:

Statistically, reliable rainfall in the November-to-December period and even into late December is possible smile ; reliable as in not the same pattern all the time, but more often than not.

As present, there have been (not including today) 41 days without a significant (noticeable) change in run-off. Although the surface barometric pressure dropped yesterday to about 998 hPa, the result (0.5 mm with a brief thunderstorm) had little or no noticeable effect on this continuing. Notably the pressure dropped below 1000 hPa (per event) 3 times in the last 41 days – 998 on the 24th of October and down to about 990 on the 5th of this month; the outcomes (with precipitable water values estimated at about 24.3 mm and 27.6 mm respectively) were little more than a trace of rain. Corresponding day-time vapour pressures (per event) were about 44 and 49% relative humidity (as opposed to something like 70-80% at night). Estimated night-time diurnal ranges (for the same period) for humidity seems to suggest a higher probability of night-time rainfall, or from late evening onwards, however this also depends on how much solar heating during the day (leading evaporation and transpiration) facilitates greater moisture content.

Precipitable water (PWAT) (a function of humidity and pressure) tells us about how many millimetres of water would be present on the surface, per square metre, if the entire water-vapour column in the troposphere condensed out. Therefore higher PWAT could imply a higher probability of rainfall if the barometric pressure falls enough (the humidity remaining steady). If the barometric pressure falls and the humidity increases, the density will increase due to the additional water vapour content (ideal gas law P = p*R*T), meaning the temperature will fall being inversely related to the density.

The day-time humidity here has not been increasing, it’s been decreasing.

Going into summer, the barometric pressure is on a steady decline, on the odd occasion declining a little further with rain events, cool changes or troughs. Therefore with the humidity falling, the pressure is down, PWAT down, day-time temperatures up (sensible heat), and the nighttime temperature down (less moisture to retain heat overnight).

The consequence – more often: a greater diurnal variation (temperature), generally low humidity, low-to-moderated barometric pressure, and thus less in the way of runoff. At the moment it seems the event(s) forecast for later this month (near the 29th I think it is) across Southern Australia (and possibly through the centre) may come about due to a change in the PWAT, exceeding perhaps 35 mm. A change (increase) in this variable with humidity decreasing beforehand seems to me to imply a change in the pressure – up – after a change in moisture levels occurs.

The two other possible consequences of the PWAT value increasing followed by a rise in the pressure are the temperature falls, and the 500-1000 mb thickness falls. Thus, after PWATs values of perhaps 35-40 mm, we could see a cold front, or even a cut-off low. A trigger to all this could be the increasing moisture with precipitable water, however as we’re heading into summer, the (surface) pressure falling, we might expect:

“on the odd occasion [the pressure] declining a little further with rain events, cool changes or troughs”.

Food for thought smile .
Posted by: Seina

Re: Streamflow Observations - 29/11/2012 12:24

Just a brief note: surface pressure as been between approx. 996 to 994 hPa since ~26th, meaning relatively speaking we seem to be in appreciable trough-like conditions, with overnight lows 10-15 deg (maxing in the 30-35 deg range). The humidity has not been impacted just yet, but I suspect it might be soon.
Posted by: Seina

Re: Streamflow Observations - 30/11/2012 17:19

Humidity has climbed...very sticky.

Going by recent GFS (AVN) forecast...flooding in the mid-north (SA)!?
Posted by: Seina

Re: Streamflow Observations - 01/12/2012 16:29

Flash flooding reported in BoM Severe Thunderstorm Warning issued 8:33 pm yesterday.
Posted by: Seina

Re: Streamflow Observations - 11/12/2012 18:05

Estimated precipitable water (PWAT) values for the previous event (circa. 29th Nov-1st Dec 2012) reached 25.3 mm specific to this area, not 35-40, let alone 40-45.

Think their yet to come, give it half a week smile .
[Note: Not a forecast see official forecasts].
Posted by: Seina

Re: Streamflow Observations - 13/12/2012 18:43

Written 11th Dec 2012 (updates italicised):
Recent GFS model runs suggest a gaping hole (area of relatively unstable low pressure) may form across the interior of Australia, bringing with it the formation of several consecutive lows forming along the northwestern coast and associated troughs (see Analysis for 06:00 UTC on Thursday 13 December 2012), allowing copious amounts of moisture to reach more southern areas of the continent, within a week.

The potential for this system, for widespread falls significantly more marked that those of the previous system seems (for Central Areas – Adelaide – and probably further to the northwest and southeast) much higher. 20-40 is some areas not out of the questions, much more robust moisture presence, relatively high CAPE sliding across the land-ocean boundary between WA and SA.

I consider it pretty early to be making these kinds of assumptions about this sort of event, and this is just my view (thing could change in the mean time), but this may have been developing from some time. Better to be prepared than not.

Update 13th Dec 2012:
Rough [expected] outcomes don’t seem to have changed.

CAPE remains relatively high, moisture likely to start picking up into night-tomorrow morning. Overnight low was 19, currently 25 after 37 with cloud-cover developing, humidity is rising (current up ~6%/3 hours from 40%).

Possible order magnitude change in flow.

On a side note, will a hypothesis re: relationship between humidity and soil moisture be supported in this case? Or even precipitable water?
Posted by: Seina

Re: Streamflow Observations - 15/12/2012 10:29

Originally Posted By: -Cosmic- (naz)
will a hypothesis re: relationship between humidity and soil moisture be supported in this case? Or even precipitable water?

8.6 mm soil moisture smile .
Posted by: Seina

Re: Streamflow Observations - 19/12/2012 17:02

Originally Posted By: -Cosmic- (naz)
Written 11th Dec 2012 (updates italicised):
Recent GFS model runs suggest a gaping hole (area of relatively unstable low pressure) may form across the interior of Australia, bringing with it the formation of several consecutive lows forming along the northwestern coast and associated troughs (see Analysis for 06:00 UTC on Thursday 13 December 2012), allowing copious amounts of moisture to reach more southern areas of the continent, within a week.

The potential for this system, for widespread falls significantly more marked that those of the previous system seems (for Central Areas – Adelaide – and probably further to the northwest and southeast) much higher. 20-40 is some areas not out of the questions, much more robust moisture presence, relatively high CAPE sliding across the land-ocean boundary between WA and SA.

I consider it pretty early to be making these kinds of assumptions about this sort of event, and this is just my view (thing could change in the mean time), but this may have been developing from some time. Better to be prepared than not.

Update 13th Dec 2012:
Rough [expected] outcomes don’t seem to have changed.

CAPE remains relatively high, moisture likely to start picking up into night-tomorrow morning. Overnight low was 19, currently 25 after 37 with cloud-cover developing, humidity is rising (current up ~6%/3 hours from 40%).

Possible order magnitude change in flow.

I believe a few things might need clarifying regarding the above smile .

Calculating basic precipitable water (PWAT) can be achieved using this link (looking down the list of parameters we find “W”). This indicates (the equation) that if PWAT is to increase while the pressure is falling, the humidity has to rise substantially (perhaps sustained at or above about 78-80% for 2-3 days or more), the temperature falling during or after a pressure trough. So far this has not happened enough to result in direct runoff (the expected part), and it remains to be seen for the remainder of the year (as the pressure continues on its annual falling trend into mid-summer) whether this will actually happen. The 20-40 mm thought to be “not out of the questions” was intended for the “relatively high CAPE sliding across the land-ocean boundary between WA and SA”, where some rain, according to the Bureau's last 1-week mapped rainfall totals to the 18th (yesterday) did fall in that bracket, even thought not really over SA (although it would have been nice smile ).

It is apparent there is an increasing presence of moisture (as well as the soil moisture mentioned in the last post) in the last few days. Streamflow remains steady/stagnant.
Posted by: Seina

Re: Streamflow Observations - 22/12/2012 10:51

Originally Posted By: -Cosmic- (naz)
It is apparent there is an increasing presence of moisture (as well as the soil moisture mentioned in the last post) in the last few days. Streamflow remains steady/stagnant.

Correction: (streamflow) water level more likely falling. The green tinge in the paddocks is fading.
Posted by: Seina

Re: Streamflow Observations - 22/12/2012 11:41

#1106840 - 30-05-2012 02:58 PM:

Originally Posted By: -Cosmic- (naz)
Not looking that flash for Central SA for the coming winter…nor Southwest WA frown .

Update for the Southwest Corner (WA)
Posted by: Seina

Re: Streamflow Observations - 29/12/2012 12:21

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
It is apparent there is an increasing presence of moisture (as well as the soil moisture mentioned in the last post) in the last few days. Streamflow remains steady/stagnant.

Correction: (streamflow) water level more likely falling. The green tinge in the paddocks is fading.

Definitely falling and fading.
Posted by: Seina

Re: Streamflow Observations - 16/01/2013 18:54

For information:
#1151050 - 19-12-2012 05:02 PM:

Originally Posted By: -Cosmic- (naz)
This indicates (the equation) that if PWAT is to increase while the pressure is falling, the humidity has to rise substantially (perhaps sustained at or above about 78-80% for 2-3 days or more), the temperature falling during or after a pressure trough.

Bold Added.

The outdoor hygrometer recorded 78-80% near the peak of onset of 12.5 mm of rain on the 13th (Jan, Sunday), which lasted for a period of 4-5 hours. This was sufficient to make a very slight difference to stream flow water levels, in addition to soil moisture.
Posted by: Seina

Re: Streamflow Observations - 23/01/2013 17:55

The water level is falling at different rates along different parts of the local river. In some areas there is no water left (it's all evaporated, about 0.25 to 0.5 metres of it), while in others it's receeding at perhaps 1-2 inches a day, less with cloud cover or even, recently, steadying with some rain. It seems very dynamic.
Posted by: Seina

Re: Streamflow Observations - 02/02/2013 21:57

Records indicate it may take approximately 10 mm (in one day) – from 2/2/2013 (today) – to increase water levels to those seen on the 4th of February last year, or about 300 to reach those witnessed in early September 2010.
Posted by: Seina

Re: Streamflow Observations - 03/02/2013 11:53

Stream flow water-levels observed on different days in a single location at about the same time in February 2012 and 2013. Might give some idea of what I meant by water levels falling.

1st February 2013:


4th February 2012:
Posted by: Seina

Re: Streamflow Observations - 10/02/2013 10:05

Prelim note: potential for trend-breaker by end of month.
Posted by: Seina

Re: Streamflow Observations - 11/02/2013 14:01

Originally Posted By: -Cosmic- (naz)
Prelim note: potential for trend-breaker by end of month.

Refer to 28-day outlook for "high" probability from this link (19th-20th, note link will update).
Posted by: Seina

Re: Streamflow Observations - 15/02/2013 20:12

Major immediate runoff and torrential rain from thunderstorm(s) (7.45 pm)!

Potential flash flooding risk!??
Posted by: Seina

Re: Streamflow Observations - 15/02/2013 22:29

Originally Posted By: -Cosmic- (naz)
Potential flash flooding risk!??

Subsided.
Posted by: Seina

Re: Streamflow Observations - 16/02/2013 11:44

A few inches increase in stream flow water level overnight laugh . Most has evaporated if not is already doing so.

Not enough time during the event to get any proper footage, but basically:

5 mins: heavy/torrential rain.
10 mins: gutters over flowing.
15 mins: water lapping at 2-3 inches deep in places.
20 mins: see "potential flooding" comment.

Probably the biggest (most prolonged and intense) convective rain event in many years.
Posted by: Seina

Re: Streamflow Observations - 16/02/2013 22:19

Originally Posted By: -Cosmic- (naz)
A few inches increase in stream flow water level overnight laugh . Most has evaporated if not is already doing so.

Hence not trend-breaking in terms of an easing of dry conditions...and the 19th-20th might have a little last-minute uncertainty as well.
Posted by: Seina

Re: Streamflow Observations - 20/02/2013 13:48

Originally Posted By: -Cosmic- (naz)
Prelim note: potential for trend-breaker by end of month.

The potential for a break in dry conditions remains - by the end of the month - but not over the period 19th-20th. While the maximum temperature fell 14 degrees from the 18th to the 19th (the minimum remained roughly the same), and the humidity rose somewhat, conditions were generally windy with only a trace of precipitation...hence a trend was only broken in statistical terms.

Hopefully this is a prelude to something more smile , but I cannot guarantee that, hence potential, not actual.
Posted by: Seina

Re: Streamflow Observations - 24/02/2013 11:11

Stream flow is gradually approaching levels of March 2010, so in many parts the river is now dry (there is no water level so I'm basically talking about isolated/disconnected pools of water). These pools appear to be either fairly deep or have the ability to retain moisture somehow.

The recent trend of falling water levels is very real...and with each passing day/week it seems to get more eye-opening. Any rain that falls needs to fall at such a rate that in gets into the soil first, with minimal runoff, although runoff that doesn’t evaporate within hours of rain falling would also be welcome – for that the evaporation rate also needs to fall (related to solar heating/cloud cover).

Looks like the best chance for a change in the water level (of any appreciable amount) might be tonight, into tomorrow (according to GFS, assuming the forecast doesn't change in the mean time). Will see smile .
Posted by: Seina

Re: Streamflow Observations - 27/02/2013 20:32

7 mm soil moisture to 8 pm today since the 25th.
Posted by: Seina

Re: Streamflow Observations - 07/03/2013 14:07

Potential for intermittent heavy rain over the next 2-3 days (GFS, Weatherzone, BoM).
Posted by: Seina

Re: Streamflow Observations - 07/03/2013 19:51

Originally Posted By: -Cosmic- (naz)
Potential for intermittent heavy rain over the next 2-3 days (GFS, Weatherzone, BoM).

1 mm in about 1/2 an hour; 0.8 in 2-3 mins (so far).
Posted by: Seina

Re: Streamflow Observations - 12/03/2013 22:50

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Potential for intermittent heavy rain over the next 2-3 days (GFS, Weatherzone, BoM).

1 mm in about 1/2 an hour; 0.8 in 2-3 mins (so far).

Potential ceased 9th March...1.8 mm total.
Posted by: Seina

Re: Streamflow Observations - 19/03/2013 23:26

Can just about walk along the middle of the river bed in several sections, including over exposed bedrock. Think that's saying something. Heard it might be the driest March in 19 years (recalled from the News, think it was 7).

As may be commonly enunciated in these circumstances about rain...

"Will believe it when I see it."
Posted by: Seina

Re: Streamflow Observations - 20/03/2013 22:28

Based on Bureau's latest forecast for Mount Barker (21/14, Max/Min Thursday March 21st), expecting a sharp change in specific humidity, precipitable water and the diurnal temperature range in the next 24-48 hours.

Last 4 days temps:

21/9, 23/5, 25/5, 30/5.
Posted by: Seina

Re: Streamflow Observations - 21/03/2013 11:06

13 degrees overnight with ~ 4 mm (soil moisture) from a thunderstorm, possibly more to follow in coming hours/days.
Posted by: Seina

Re: Streamflow Observations - 26/03/2013 18:02

My Views - Written 23rd, Updated Yesterday (25th), with observations for today:

An interpretation of the likely/past weather conditions, 23rd to the 31st of March 2013 (inclusive):

After a prolonged period of dry conditions in which water levels have dropped to such an extent that (in sections of the river) bedrock is not only exposed, it too is dry or drying…

Streamflow, 24th of March 2013 – Looking Downstream:



…a recent change in weather conditions (starting the 20th of March, 8.1 mm over ~ 3 days) seems to suggest a more robust, rain-bearing change is on the way (or more than one gradually in the coming weeks to a month). This can been seen in both in a consistency of forecasts (mentioned below), and observations. While there is again no guarantee this will happen (in the next few days) it is, as reiterated below, promising smile .

On the following days (24th to 30th March 2013) the Bureau indicated (4:15 pm CDT forecast, 23rd March for Adelaide) that the maximum day-time temperature was expected to increase towards 32 deg C by the 26th, before falling back to the mid-to-low 20s by the 28th. The minimum night-time temperature was expected to increase from the 23rd to peak around 23 deg C on the 27th. The diurnal differences (according to the forecast at the time) were 9, 13, 14, 9, 5, 8 and 8 for the 24th to Saturday the 30th respectively. The maximum daily temperature appeared to be increasing towards the 26th-27th at a greater rate than the increase in daily minimum. While this suggested higher dew points due to correspondingly higher minimums, this could be offset by the change in diurnal range, meaning the maximum temperature was rising rather than falling (i.e. lower humidity); the latter – a fall – likely resulting in both an increase in the dew point and humidity.

The updated diurnal differences (one day on, 24th) of 13 (25th), 17 (26th), 5 (27th), 5 (28th), 8 (29th), 8 (30th), and 10 deg C (31st) indicated a more pronounced change from a difference of 17 deg C to 5, 26th to 27th. If the maximum temperature was to fall at a slower rate (23rd to 27th) than the minimum, this may mean less chance of rain than if the diurnal difference itself simply reduced (i.e. the day-time maximum approached the previous minimum), which now seems to be more likely (as of the 24th).

The likelihood of solid rain is increased by (according to Weatherzone; ACCESS G, GFS, ACCESS R, + 72HRS, runs for 23rd, 24th and +48 HRS for 25th) a robust change in pressure – forming pre-frontal trough and low – and a change in the 500-1000 millibar thickness associated with the temperature. In this situation, as the pressure changes about a day out from rain (currently 998 Sfc. P, 31% RH @ 3:30 pm, 26th) (first increasing slightly then falling sharply) the humidity falls sharply, meaning the specific humidity also falls. As the trough approaches, this gradient (in specific humidity) reverses, sharply, as the humidity increases as the pressure falls.

As indicated by the change in the diurnal temperature range, it increases and then decreases – the dew point increasing, as the humidity falls towards the 26th-27th. For the precipitable water to be impacted, the change in specific humidity needs to reverse in such a way that supports the advection of moisture (possibly a northwest in-feed), which a drop in pressure may assist (i.e. convection and moderated temperatures and dew points over land). Assuming an accompanying front or low (behind the trough), this would bring a change in temperature and thickness.

With an increase in atmospheric moisture supported by a change in specific humidity, dew point and a pressure trough, that moisture needs a trigger to fall out of the sky – a change in temperature. How long it will rain for would likely depend very much not just on how much moisture is in the air, but on how long it can be sustained for. According to the Bureau’s chances of rain (27th), there is at least 90% chance of 1 mm (over Central Districts), grading to 50% chance of 5 mm, 25% chance of 10mm, and 10% chance of 15 mm (update: 10% of 15 mm, 25% to 10 mm). Based on this alone we may not expect much, however the consistency of the ACCESS-G, R and GFS forecasts for the last 3 days suggests it might be somewhat higher.

The expected change in both the temperature and the pressure support the Weatherzone forecast (for tomorrow, 26th) of increasing winds and wind speeds (more so in the afternoon).

This is just my view based on recent dynamics:
I believe this may mean 15-20 mm (locally), possibly 20-35 (localised), if the forecast does not change much in the next day or two. I think that might be bit conservative given the expected/forecast temperature gradient 26th-28th.

There may have been a slight chance of light rain today (25th), due to the aforementioned moderation of temperatures and dew points over land (already somewhat apparent, 25th), preceding the upward temperature change. Temperatures since the 30 degrees recorded on the 20th have not been higher (and no higher than 30 since the 12th), so the (update: 34 deg, Mount Barker) forecast for tomorrow (26th), may break another run of temperatures below 30 degrees.

In practice conditions and variations need to support the chance of this (26th-onwards) happening more than not, and the signs definitely seem encouraging for that period smile .

…26th: 33/9, Max/Min. Increasing winds and wind speeds..

Waiting for (what’s left of) stream water levels to increase substantially...
Posted by: Seina

Re: Streamflow Observations - 29/03/2013 12:34

The minimum temperature overnight 26th-27th rose from 9 and 21 deg C, while the maximum dropped from 33 to 23. This could have meant that while the rain band had higher moisture content, the temperature gradient did not favour significant falls because the minimum rose substantially rather than moderately (say 9 to 16) => reality was 33 – 23 = 10 and 9 – 21 = –12, rather than 10 and –7. A possible interpretation of this is the minimum rising so much meant the pressure on precipitable water to rain out was not there.

The last time the overnight low equaled or exceeded 20 was 51 days ago from the 27th.
Posted by: Seina

Re: Streamflow Observations - 30/03/2013 11:00

Fall in (max, min) temperature 27th-28th – rainfall in parts of the hills.
(http://www.bom.gov.au/cgi-bin/wrap_fwo.pl?IDS60160.html)
Note link will update.
Posted by: Seina

Re: Streamflow Observations - 05/04/2013 12:35

The observations of the opening post of this thread could be at risk of being exceeded (in record-breaking terms) if conditions continue the way they are for another 1-2 months.
Posted by: Seina

Re: Streamflow Observations - 12/04/2013 13:59

Type "Percent Rank Relative Soil Moisture (Upper Layer)" or "Percent Rank Relative Soil Moisture (Lower Layer)" in Google to find recent maps for all of Australia smile .
Posted by: Seina

Re: Streamflow Observations - 17/04/2013 12:43

Threshold of dry river conditions equalled or exceeded circa 17th April 2013 (observational equivalent of 11th May 2010).
Posted by: Seina

Re: Streamflow Observations - 11/05/2013 10:38

Streamflow may be moderately impacted in the next few days.
Posted by: Seina

Re: Streamflow Observations - 15/05/2013 11:28

Originally Posted By: -Cosmic- (naz)
Streamflow may be moderately impacted in the next few days.

Definitely not.
Posted by: Seina

Re: Streamflow Observations - 17/05/2013 23:35

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Streamflow may be moderately impacted in the next few days.

Definitely not.

22.8 mm total 11th to 16th May 2013.
Posted by: Seina

Re: Streamflow Observations - 18/05/2013 00:17

Correction to last post +2.
Posted by: Seina

Re: Streamflow Observations - 18/05/2013 16:42

Written 17th of May 2013 at 11.15 pm CST:

Reference #1189902:
Obs, 11:15 pm, 17th May 2013: Currently 75% relative humidity, 1016 hPa surface pressure and 1 deg C (also the overnight low, 17th-18th). Streamflow water level slightly above threshold.
Posted by: Seina

Re: Streamflow Observations - 22/05/2013 15:38

Continuation from previous reference – conditions now more conducive to substantial falls.

Temperature was 12 deg C today (currently 11). Overnight low of 9; humidity now 79-80% (at/above rainfall threshold), pressure 1001 hPa (~ 1010 MSL). Steady rain/drizzle for 2.5 hours (3 pm CST). Potential thunderstorms/probable scattered showers in the next 24-48 hours (BoM, WZ, ACCESS-R). Potential for water level to be slightly-to-moderately affected by the 24th if current forecast(s) (as of 3 pm CST) holds or upgrades.
Posted by: Seina

Re: Streamflow Observations - 23/05/2013 13:57

System track was not as thought.

14.2 mm to 9 am today since midday 21st. Very slight to slight change in water level - little or no runoff.
Posted by: Seina

Re: Streamflow Observations - 25/05/2013 16:21

In the process of understanding a possible relationship / connection between rainfall / upper-soil moisture estimates and relative humidity locally in the Adelaide Hills smile .

Question: can knowing the advection of moisture (precipitable water) in advance of a possible rainfall system (and through it, the relative humidity) provide information about soil conditions / streamflow to come?
Posted by: Seina

Re: Streamflow Observations - 29/05/2013 12:48

Increasing probability of moderate falls (10-20 mm, possibly 20-40 mm over 3-4 days) in the next couple of days (BoM, WZ) - will moisture levels be enough to lead to a moderate change in water level, or even flow?

River has not been flowing properly for months.
Posted by: Seina

Re: Streamflow Observations - 30/05/2013 16:45

There is the potential for a sharp change in 500-1000 mb thickness (GFS) between today and the 2nd of June 2013, Central SA.

The probability has increased (30th May 2013) sufficiently that the rainfall amounts previously indicated are highly likely within SA, with higher falls possible locally.

The response of runoff could also be potentially sharp due to the infiltration of moderate quantities of moisture into the upper soil layers in recent weeks – the paddocks are green, but the river is not flowing.
Posted by: Seina

Re: Streamflow Observations - 31/05/2013 21:19

Originally Posted By: -Cosmic- (naz)
The response of runoff could also be potentially sharp due to the infiltration of moderate quantities of moisture into the upper soil layers in recent weeks – the paddocks are green, but the river is not flowing.

Bold Added.

River is flowing (audible - roaring), water level has risen dramatically (8.40 pm CST) - river level has risen 2-3 metres in places in a very short period of time.
Posted by: Seina

Re: Streamflow Observations - 10/06/2013 13:37

2nd Temporary Flash-flood Event, Witnessed 31st May 2013, Upper Onkaparinga Catchment [1st in December 2010]:
See #897948 - 13-11-2010 10:19 PM (very similar):

Originally Posted By: -Cosmic- (naz)
Peak 2009:



The dramatic change in water level (31st May 2013) was predominantly due to a flash flood where the river rose to levels not seen since just before for a minor flood event in early September 2010. This is apparent from the fact the grass and small vegetation growing in the river bed (in the wake, 2nd June) is angled / bent / flattened in the downstream direction. I am thinking heavier rain probably fell further upstream (Charleston / Lobethal). 48.8 mm was recorded on the 31st, with an additional 25.5 mm the following 24 hours (48 hour total 74.3). The river water level (5 pm 7th June 2013) was maintaining 1-2 metres (steady) above what it was prior to the 31st of May smile ...and flowing (just).

Notes:

Although there was not as sharp a fall in the 500-1000 millibar thickness as first thought per GFS (the overnight low reaching zero did not eventuate), the low-pressure system in the wake of the formation of the northwest cloud band passing over Central SA areas seemed to provide ample change (gradient) in the surface atmospheric pressure (from 1009 hPa on the 30th, to 1002 on the 31st, followed by a return to values 1016-1019 the next day) for the diurnal temperature range to narrow sharply over the period 31st May to 6th June. The mean maximum and minimum during that period were about 13.8 and 7.9 degrees C respectively. Beyond the 31st, no maximum over 20 has been recorded (to 10th June).

Coming (3-4) Weeks (as of Monday 10th June 2013):

More rain appears to be forecast (WZ, BoM, GFS) this coming week (Tomorrow-Wednesday, or thereabouts). With the overnight lows falling (2 degrees C on the 8th June) and the maxima remaining about the same (~12-15 degrees), it seems to diurnal range could narrow yet again, this time, possibly, bringing the temperature down further (into the 10 to -5 deg range). One important factor might then be cloud-cover – an indicator of moisture in the lower atmosphere. More of this may mean less chance of frosts and vice versa (in theory). Whatever is the case, it appears winter temperature ranges and variations (at least preliminarily) are setting in.

One more note: below is a rough guide as to streamflow conditions or expected conditions under changing moisture levels in the immediate atmosphere and soil environments smile .

Streamflow in context (one perspective, a guide only (winter)):

The streamflow conditions below are satisfied when streamflow remains the state for at least 3-5 days. Longer that 3-5 days may be considered a steady-state period. The threshold for a change in steady-state conditions is about is a lack of rain for 2 days at a rate of 3-4 mm/hour, or vice versa, or about 78-80% sustained humidity over 3-4 days, which is thought to affect soil moisture.

Severe drought conditions: 0-10 cm water level, level of water table (cumulative rainfall totals -3 to -5 metres below riverbank, lack of moisture on intermediate- and deep-soil layers (0 to 5% soil moisture)).

Significant drought conditions: 10-20 cm water level (cumulative rainfall totals -4 to -3 metres below riverbank, lack of moisture in deep-soil layers (5 to 10%)).

Moderate drought conditions: 20-50 cm water level (cumulative rainfall totals -3 to -2 metres below riverbank, all soil layers have at least slight moisture content (10 to 20%)).

Mild drought conditions: 50 cm to 1 metre (cumulative rainfall totals -2 to -1 metres below riverbank, all soil layers have at least mild moisture content (15 to 20%)).

Slight drought conditions: 1-1.5 metres (cumulative rainfall totals -1 to -0.75 metres below riverbank, all soil layers have moderate moisture content (20 to 25%)).

Average conditions: riverbank level 0 metre datum (2 metres) (cumulative rainfall totals yield all soil layers have moderate-to-significant moisture content (25 to 30%)).

Potential flooding: 2-3 metres (water level encroaches on riverbank; cumulative rainfall totals yield all soil layers have significant moisture content (30 to 35%)).

Minor flooding: 3-4 metres (flooding of low-lying areas within 10-15 metres of riverbank; cumulative rainfall totals yield all soil layers have significant moisture content (35 to 40%)).

Moderate flooding: 3.5-5 metres (flooding of low-lying areas within 15-20 metres of riverbank; soil fully saturated).

Significant flooding: 4.5-7 metres (flooding of middle ground within 20-30 metres of riverbank).

Major flooding: 7+ metres (flooding within 30-100 metres of river bank).

Flow rate (velocity) thought to increase exponentially beyond threshold conditions, at higher flow rates there is a possible risk to livestock, property and infrastructure.

Currently increasing cloud-cover and 15 deg C.
Posted by: Seina

Re: Streamflow Observations - 30/06/2013 16:22

I'm going to ask this once more. I have some information relating to this thread and I find it pertinent to quote:

"Coming (3-4) Weeks (as of Monday 10th June 2013)"

in order for it to make sense. I also (with journal references) will be referring to the Southern Annular Mode, Sub-tropical Ridge and El-Nina Southern Oscillation/Indian Ocean Dipole. Is this possible?
Posted by: Seina

Re: Streamflow Observations - 02/07/2013 16:51

Summary (3 weeks / 23 days later):
Whether or not it rains significantly in the next few weeks may depend strongly on whether the dew point temperature remains mostly negative, or increases sharply enough in a short period of time (hours to days). The former seems (per the last few weeks) conducive to the development of frosts, the latter, rain or hail. From the 31st of June to the 1st July the overnight low increased from 1 to 9 degrees C.


Hypothesis:
A change in the latitude and / or strength of the sub-tropical ridge may provide a mechanism for generating favourable sea-surface temperature conditions off the north-western coast of WA, and assist the development of a north-west cloud-band and subsequent cold front (Larsen and Nicholls, 2009 [1]; Evans et al. 2009 [2]).

[1]: Geophysical Research Letters, Vol. 36, L08708, doi:10.1029/2009GL037786, 2009. Abstract.
[2]: Clim Dyn (2009) 33:477–493, doi 10.1007/s00382-008-0461-z.

Streamflow (particularly runoff) appears to be steady though gradually receding.
Posted by: Seina

Re: Streamflow Observations - 03/07/2013 10:41

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
The response of runoff could also be potentially sharp due to the infiltration of moderate quantities of moisture into the upper soil layers in recent weeks – the paddocks are green, but the river is not flowing.

Bold Added.

River is flowing (audible - roaring), water level has risen dramatically (8.40 pm CST) - river level has risen 2-3 metres in places in a very short period of time.

For information, one of the most significant and noticeable changes in flow I have witnessed in a short period of time in years. Potentially coincided with an abrupt shift in the sub-tropical ridge per 1st reference in last post.
Posted by: Seina

Re: Streamflow Observations - 03/07/2013 10:58

#1202105 - Edit Note: 30th June, not 31st.
Posted by: Seina

Re: Streamflow Observations - 06/07/2013 10:19

River has responded quite quickly to 35.5 mm to 9 am since the 30th of June, and flow is now fairly steady. Frequent moderate-to-heavy showers continue.
Posted by: Seina

Re: Streamflow Observations - 13/07/2013 10:31

59.9 mm in the 120 hours to midnight on the 8th of July 2013, plus another 21.2 mm, 12 midnight yesterday to 9 am this morning (most of that falling overnight 12th-13th) brings the river to moderate flow conditions.

The guide to streamflow and soil-moisture conditions in post #1198291 may need to be revised.
Posted by: Seina

Re: Streamflow Observations - 14/07/2013 09:53

The response of the local river water volume and speed to rainfall is becoming quicker with each passing weather system. Run-off is increasing as surface water becomes more apparent. This appears to imply less rain is infiltrating upper soil layers.

Should not next [significant] weather system yield moderate-to-major rainfall, I would think [moderate] flooding is possible (per the guide provided previously).

It also appears that within the space of 3-4 months contrasting weather patterns are emerging this year.
Posted by: reckless

Re: Streamflow Observations - 14/07/2013 12:06

Don't see that very often. Currently Brisbane, Sydney, Melbourne, Perth and Adelaide are all on 16 degrees.
Posted by: Seina

Re: Streamflow Observations - 15/07/2013 21:34

Originally Posted By: reckless
Don't see that very often. Currently Brisbane, Sydney, Melbourne, Perth and Adelaide are all on 16 degrees.

Unless it's an error of some kind, today's max in Adelaide was about equal to locally.

Preliminary estimates indicate streamflow could increase from the current approx 0.3 metres to possibly 1.12 (proxy, local obs, also see GFS MSLP maps/Bureau Mt. Barker forecast) within 3-4 days.

[Disclaimer: guide only]
Posted by: Seina

Re: Streamflow Observations - 19/07/2013 17:02

Written 17th July 2013:

Originally Posted By: -Cosmic- (naz)
Preliminary estimates indicate streamflow could increase from the current approx 0.3 metres to possibly 1.12 (proxy, local obs, also see GFS MSLP maps/Bureau Mt. Barker forecast) within 3-4 days.

[Disclaimer: guide only]

Now ~ 1.5 metres by Saturday 20th July.* [see also flood level BoM]
Update ~ 1.78 today by Sunday. Estimated total rainfall 18th-24th: 64.5 mm* (conservative estimate).

* Valid for 18th to 24th July 2013.

Pressure has dropped and thickness is forecast (BoM, GFS) to fall to perhaps 5340 metres with chance of sleet / snow on higher ground south of about the Flinders Ranges (BoM).

[18th July MSLP – 1003 hPa – was ~1 hPa higher than forecast by GFS day before.]
Latest BoM flood level (3:38 pm CST 19th July): 0.89 metres, peak 0.96 between 12 midday-2 pm.

Will go with 110-130 mm by the 24th (currently 40.1 mm since 18th), but might change again.
Posted by: Seina

Re: Streamflow Observations - 20/07/2013 10:58

Originally Posted By: -Cosmic- (naz)
Written 17th July 2013:

Originally Posted By: -Cosmic- (naz)
Preliminary estimates indicate streamflow could increase from the current approx 0.3 metres to possibly 1.12 (proxy, local obs, also see GFS MSLP maps/Bureau Mt. Barker forecast) within 3-4 days.

[Disclaimer: guide only]

Now ~ 1.5 metres by Saturday 20th July.* [see also flood level BoM]
Update ~ 1.78 today by Sunday. Estimated total rainfall 18th-24th: 64.5 mm* (conservative estimate).

* Valid for 18th to 24th July 2013.

Pressure has dropped and thickness is forecast (BoM, GFS) to fall to perhaps 5340 metres with chance of sleet / snow on higher ground south of about the Flinders Ranges (BoM).

[18th July MSLP – 1003 hPa – was ~1 hPa higher than forecast by GFS day before.]
Latest BoM flood level (3:38 pm CST 19th July): 0.89 metres, peak 0.96 between 12 midday-2 pm.

Will go with 110-130 mm by the 24th (currently 40.1 mm since 18th), but might change again.

Notes of Benefit (for those interested):
  • The estimated flow height depends on the weather being consistently wet for a prolonged period of time; in other words, once the Sun starts to come out or the rain rate drops for more than a few hours below 3-4 mm per hour, this probability diminishes significantly.
  • The 64.5 mm mentioned is conservative, meaning middle of the range. The falls 110-130 mm are therefore an upper limit, meaning they take into account as much as possible.
  • The chance of sleet / snow means showers or consistent and prolonged periods, not just a few flakes or single shower.
  • At least 78-80% humidity or 3-4 mm per hour must be sustained for 2-3 days (under current conditions) for significant flooding to be possible. So far for this period (ending 24th) this has not been the case.
Posted by: Seina

Re: Streamflow Observations - 22/07/2013 12:38

The Woodside Weir water level reached 1.12 metres at 11:38 am this morning. Water is lapping the riverbank in places. See here, link will update.

14.8 mm overnight (6.40 pm to 9 am) brings the system total to 78.2 to 9 am, showers to follow.
Posted by: Seina

Re: Streamflow Observations - 06/08/2013 21:45

After 25.5 mm to 2.30 pm CST today since the beginning of August (this year) the recession rate in the streamflow water level (gradual decline of water level from peak flow conditions towards a steady state) is nearing the 0.2 m mark, per link in previous post. This appears to indicate healthy flow conditions and a moderately rapid response/onset of runoff after moderate rains.
Posted by: Seina

Re: Streamflow Observations - 08/08/2013 22:05

River Height for King River at Docker Road Bridge (582004, Victoria) at approximately Moderate Flood Level (link will update) at ~ 21:16, 6th August 2013 station time, Other gauges at Minor Flood Level in the area. Forecast (BoM) range 25-100 mm, 8 days 6th to 13th August 2013.

Update: Gauge steady at approx. moderate flood level since gauge time above. Rainfall in the area or near-west 25 to 49 mm (BoM) to 9 am this morning. Currently at gauge time 20:49 8th August water level is 4.00 m. See Victorian Flood Warnings for more information.

Outlook for region ~ +80% chance of exceeding median rainfall August to October 2013 (BoM).
Posted by: Seina

Re: Streamflow Observations - 11/08/2013 20:35

71 days of the maximum temperature registering less than or equal to ~ 17 deg C broken by 2 days ~ 19 deg.

4.55 pm CST Bureau forecast for Adelaide: 70% chance of 1 to 3 mm tomorrow (may affect streamflow slightly-to-moderately in next 1-2 days, possibly 2-3 days, not just in Central SA).
Posted by: Seina

Re: Streamflow Observations - 12/08/2013 18:17

Originally Posted By: -Cosmic- (naz)
71 days of the maximum temperature registering less than or equal to ~ 17 deg C broken by 2 days ~ 19 deg.

Meaning a slight change in the general weather pattern occurred. The tendency of the pattern towards more contrasting diurnal ranges in the last 1-2 weeks seems to imply (within this region, and over the next week or so), more extremes and unsettled weather.
Posted by: Seina

Re: Streamflow Observations - 14/08/2013 10:59

Originally Posted By: -Cosmic- (naz)
4.55 pm CST Bureau forecast for Adelaide: 70% chance of 1 to 3 mm tomorrow (may affect streamflow slightly-to-moderately in next 1-2 days, possibly 2-3 days, not just in Central SA).

29.4 mm in the 64 hours to 10 am today. Slight change in flow.
Posted by: Seina

Re: Streamflow Observations - 15/08/2013 13:12

If one looks at the link from post #1204987, one will find the streamflow volume and speed (and thus water depth) increased moderately between about 11 am and 1 pm gauge time yesterday. While there were light falls locally (< 0.5 mm), further north (upstream) higher rainfall totals were recorded, including in the 24 hours prior to 1 pm. This might give a plausible explanation as to why the local river responded in the way it did in only a couple of hours.

The next system, per local observations and (weather) model outlooks, could potentially bring a significant-to-major change in runoff.

#1206485:

Originally Posted By: -Cosmic- (naz)
After 25.5 mm to 2.30 pm CST today since the beginning of August (this year) the recession rate in the streamflow water level (gradual decline of water level from peak flow conditions towards a steady state) is nearing the 0.2 m mark, per link in previous post [#1204987]. This appears to indicate healthy flow conditions and a moderately rapid response/onset of runoff after moderate rains.

[] Added.

The current rate of recession is above the 0.2 mark (see quote link), more than 24 hours after it stopped raining.
59.4 mm to 12 am 15th August 2013 (month so far).

I look forward to finding out just how significant the weather events of the next week will be in affecting runoff smile .
Posted by: Seina

Re: Streamflow Observations - 15/08/2013 13:55

Originally Posted By: -Cosmic- (naz)
I look forward to finding out just how significant the weather events of the next week will be in affecting runoff smile .

2 weeks.
Posted by: Seina

Re: Streamflow Observations - 18/08/2013 16:52

Originally Posted By: -Cosmic- (naz)
The next system, per local observations and (weather) model outlooks, could potentially bring a significant-to-major change in runoff.

The largest change in runoff so far (link in post #1204987) since the morning of the 16th has been ~ 0.86 m from 0.21. That's 1.07/0.21 ~ 5.1 fold change, which might be considered significant.

Translated, 0.86 m depth over 1 square metre is ~ 860 litres per cubic metre.
Posted by: Seina

Re: Streamflow Observations - 22/08/2013 14:16

The stream flow response (in-field obs) appears to be becoming more sensitive to changes in rainfall in the last 24-48 hours.

2.43 inches since the morning of the 16th.
Posted by: Seina

Re: Streamflow Observations - 23/08/2013 13:33

It seems interesting that the Bureau forecast for Adelaide (8.54 am CST today) has 100% chance of a few showers easing.

After 2.618 inches (66.5 mm) over 6 days, the water / rainfall from the last 1-2 days is still visible on the surface in swathes, with intermittent drizzle.
Posted by: Seina

Re: Streamflow Observations - 03/09/2013 18:24

It has now been over 2 weeks since the 15th of August.

After two significant changes in flow (16th and 21st August), a third change (29th) suggested the infiltration process was saturated by the 21st, with a run of 4 days of no rain following…the moisture likely soaked in, evaporated and transpired.

This seems to imply the next time there is moderate rain, moisture will have already been in the soil and soaked in, which means that if rain continues over a 1-2 day period, it is possible thresholds for runoff could be exceeded earlier.

The next time potentially moderate falls seem likely is within a week smile .
Posted by: Seina

Re: Streamflow Observations - 04/09/2013 11:51

Originally Posted By: -Cosmic- (naz)
The next time potentially moderate falls seem likely is within a week smile .

In theory…several days in a row with relatively clear skies (to the 2nd of September), moderately-increasing near-surface temperatures and moderately-high pressures seem to indicate a slight fall in the density in the last 1-2 days (2nd and 3rd – with highs of 30 and 27 degrees respectively) . The clear skies during the night allow more heat to escape to space, which removes much of the evaporative and transpiring components for latent heat flux, hence a corresponding slight fall in the relative humidity (into the 30-40% bracket) during the day. This seems to be bring a slightly higher-dew point heat during the day…

…because the pressure is relatively high, the downward influence of a drop in pressure is absent (moisture accumulates in the lower troposphere rather than rains out, and the winds are mostly calm).

This (accumulation) leads to higher precipitable water values (in theory), which may affect the capacity of the lower troposphere to hold water vapour. As the density starts to increase due to increased water vapour, the inverse relation between the density and temperature begins to take effect.
Posted by: bd bucketingdown

Re: Streamflow Observations - 04/09/2013 17:55

Cosmic in a opposite to what one might think naturally, moist air is less dense than dry air actually!
cheers
Posted by: bd bucketingdown

Re: Streamflow Observations - 04/09/2013 17:57

why is moist air less dense than dry air?

METEOROLOGIST JEFF HABY

The units of density are mass divided by volume (m/V). Density will increase if either mass increases while the volume remains constant or if volume decreases while mass remains constant.

Density of air will vary as the temperature and moisture content in the air varies. When the temperature increases, the higher molecular motion results in an expansion of volume and thus a decrease in density.

The amount of water vapor in the air also effects the density. Water vapor is a relatively light gas when compared to diatomic Oxygen and diatomic Nitrogen. Thus, when water vapor increases, the amount of Oxygen and Nitrogen decrease per unit volume and thus density decreases because mass is decreasing.

The two most abundant elements in the troposphere are Oxygen and Nitrogen. Oxygen has an 16 atomic unit mass while Nitrogen has a 14 atomic units mass. Since both these elements are diatomic in the troposphere (O2 and N2), the atomic mass of diatomic Oxygen is 32 and the diatomic mass of Nitrogen is 28.

Water vapor (H2O) is composed of one Oxygen atom and two Hydrogen atoms. Hydrogen is the lightest element at 1 atomic unit while Oxygen is 16 atomic units. Thus the water vapor atom has an atomic mass of 1 + 1 + 16 = 18 atomic units. At 18 atomic units, water vapor is lighter than diatomic Oxygen (32 units) and diatomic Nitrogen (28 units). Thus at a constant temperature, the more water vapor that displaces the other gases, the less dense that air will become.

You may be familiar with the concept that moist air is less dense than dry air. This is true when both have the same temperature or when the moist air is warmer. Said in another way, air with a greater percentage of water vapor will be less dense than air with a lesser percentage of water vapor at the same temperature. Often people erroneously believe that moist air is denser than dry air because very moist air is more difficult to breathe than dry air.
Posted by: Seina

Re: Streamflow Observations - 05/09/2013 22:49

Originally Posted By: bd bucketingdown
why is moist air less dense than dry air?

METEOROLOGIST JEFF HABY

The units of density are mass divided by volume (m/V). Density will increase if either mass increases while the volume remains constant or if volume decreases while mass remains constant.

Density of air will vary as the temperature and moisture content in the air varies. When the temperature increases, the higher molecular motion results in an expansion of volume and thus a decrease in density.

[...]

[] Added.
I wasn’t actually thinking about the mass of dry vs. moist air, but thanks nonetheless smile .
Posted by: Seina

Re: Streamflow Observations - 10/09/2013 22:39

Just to clarify, in post #1209077, the emphasis was on (a lack of) wind speed, which is why the words "accumulates" and "accumulation" were mentioned in relation to the movement of moisture in the riparian environment.
Posted by: teckert

Re: Streamflow Observations - 11/09/2013 13:07

Hey Naz.... looks like the catchment could see 60mm+ by this time next week! Nice top up for the reservoirs!
Posted by: Seina

Re: Streamflow Observations - 11/09/2013 14:05

Originally Posted By: teckert
Hey Naz.... looks like the catchment could see 60mm+ by this time next week! Nice top up for the reservoirs!

That would be good smile .

Edit: was thinking there might be something on the way, just seemed a question of how much. Promising anyway.
Posted by: Seina

Re: Streamflow Observations - 11/09/2013 14:19

The infiltration process has been below saturation level for a while (days to weeks) now locally, so that seems another good sign - it means the moisture from previous systems has soaked in, so there's then a change in the capacity of the [catchment] system to store / retain moisture before runoff occurs.
Posted by: Seina

Re: Streamflow Observations - 12/09/2013 12:46

After checking (estimates + models) again this morning, I'm going jump on board the 60+ mm idea smile .
Posted by: Seina

Re: Streamflow Observations - 14/09/2013 15:20

The last 48 hours of flow change on the Bureau's website for station 523714 appears to demonstrate the quick-flow response after about an inch of rainfall, when rain from previous systems has soaked in.
Posted by: Seina

Re: Streamflow Observations - 16/09/2013 10:39

Surface Pressure is down to 992 hPa (Nuriootpa [BoM] was on 1000.7 MSL at 9 am), with RH at 85%...overnight low 10 deg C. Been pi''ing down sporadically since the early hours. 7 mm in less than 24 hrs.
Posted by: Seina

Re: Streamflow Observations - 16/09/2013 12:50

Nuriootpa MSLP @ 12 pm CST: 999.8 hPa.
Posted by: Seina

Re: Streamflow Observations - 17/09/2013 21:43

Flow levels yesterday reached a height (station 523714) not seen since about the 13th of August. 15.9 mm in the last 3 days smile . 47.4 since the 5th.
Posted by: Seina

Re: Streamflow Observations - 17/09/2013 23:49

Written 12.20 pm 12th September 2013:

An estimate of possible falls indicated (Wednesday 11th) the highest probability of a noticeable change in streamflow would be Sunday-Monday next week. The other (smaller) potentials were Tuesday (10th) and Friday (tomorrow). Tuesday had a similar potential to next Monday with similar surface pressure (995-996 hPa). The total [rainfall] Thursday to next Friday was ~ 43 mm (11th), and is now something like 67 (12th).

Update (15th): It now seems possible the pressure will remain relatively low for 2-3 days from Sunday (probably mid-990s, 5.15 pm CST pressure 994 sfc) – could be looking at some rather large totals. CAPE is forecast to be considerable for the (2-3 day) period (GFS) given recent systems.

Seems heavy downpours may be possible across SA over the next 48-72 hours.

There also seems to be a higher probability for Thursday (19th) however it is some time out (in daily terms).

Update (17th): Thursday system now Tues-Wed smile !? Another 10-15 mm or more!?

Total rainfall 12th-today: 42.8 mm (9 am).

Sfc. Pressure 991 hPa 16th.

[Disclaimer: Guide Only]
Posted by: Seina

Re: Streamflow Observations - 18/09/2013 13:55

Originally Posted By: -Cosmic- (naz)
The infiltration process has been below saturation level for a while (days to weeks) now locally, so that seems another good sign - it means the moisture from previous systems has soaked in, so there's then a change in the capacity of the [catchment] system to store / retain moisture before runoff occurs.

It has taken some time (months), but in the space of less than 12 hours, the water level rose from something like 0.25 m to 0.91 (see previously mentioned site).

The river after 14.7 mm this morning:



Posted by: Seina

Re: Streamflow Observations - 18/09/2013 16:19

Above photos taken at ~ 8.50 am CST.
Posted by: Seina

Re: Streamflow Observations - 22/09/2013 13:40

Originally Posted By: -Cosmic- (naz)
The total [rainfall] Thursday to next Friday was ~ 43 mm (11th), and is now something like 67 (12th).

Total rainfall for the period 12 am Thursday 12th of September to 12 pm Saturday 21st September 2013 was 67.2 mm.

Local streamflow (523714) has subsided back to about 0.2 m.
Posted by: Seina

Re: Streamflow Observations - 23/09/2013 22:57

Southern Australian Rainfall – References
Posted by: Seina

Re: Streamflow Observations - 09/10/2013 13:35

[In my view] slight potential for downpour/s in (over) the next week. Moderate potential for showers. Expected impact on streamflow depends on rain rate roughly:

- 5-10 mm/day (slight, showers) (say 70% chance);
- 10-20 mm/day (slight-moderate, showers/rain) (half of 70%);
- 20-40 mm/day (moderate, rain) (1/3 of 35%);
- 40-80 mm/day (significant, downpour/s) (1/3 of 12%).
Posted by: Seina

Re: Streamflow Observations - 16/10/2013 17:18

Impact of rain/showers on streamflow over the last week has been minimal; less than 10 mm recorded.

Overnight low has been roughly stable since about the 28th of August, however is showing signs of declining again [actual decline yet to be seen].
Posted by: Seina

Re: Streamflow Observations - 21/10/2013 15:30

Visible increase in stream flow without rainfall yesterday (20th Oct); cause unknown.
Posted by: Seina

Re: Streamflow Observations - 25/10/2013 16:31

Originally Posted By: -Cosmic- (naz)
Impact of rain/showers on streamflow over the last week has been minimal; less than 10 mm recorded.

Overnight low has been roughly stable since about the 28th of August, however is showing signs of declining again [actual decline yet to be seen].

30.1 mm recorded since the 10th of October. Negligible impact on flow.
More zero/sub-zero overnight lows now apparent.

Originally Posted By: -Cosmic- (naz)
Visible increase in stream flow without rainfall yesterday (20th Oct); cause unknown.

Cause remains unknown, possibly natural.
Posted by: Seina

Re: Streamflow Observations - 05/11/2013 16:53

Written 1st November 2013, [added 3rd]:

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Impact of rain/showers on streamflow over the last week has been minimal; less than 10 mm recorded.

Overnight low has been roughly stable since about the 28th of August, however is showing signs of declining again [actual decline yet to be seen].

30.1 mm recorded since the 10th of October. Negligible impact on flow.
More zero/sub-zero overnight lows now apparent.

The minimum overnight low now appears to have broken through the 5-degree threshold – lowered, while the maximum (since the 28th) is gradually increasing, suggesting a shifting diurnal range; it’s increasing. An increasing diurnal range may imply lower dew-points and lower humidity. Since the 10th of October a general fall in the relative humidity from about 60% to around 35-40% has been observed. In theory soil moisture has also fallen in that time with increased evaporation and reduced cloud-cover, which now seems apparent since the last weather system to affect the soil (14 mm rain 16th-17th last month).

The minimum temperature profile since the 1st of August almost resembles a mirror reflection.

All of this seems to indicate the dew-point temperature is going increase this month, which may mean the pressure peaks before falling somewhat, or precipitable water increases, or both. [If both occur, the diurnal range could narrow]. In any case, the chance of [steady] rainfall is increased under the condition of more moisture [and increased cloud-cover] in the atmosphere smile .

Today:
The next period with a chance of rain or showers [Bureau] could affect run-off as well as soil moisture.
Posted by: Seina

Re: Streamflow Observations - 09/11/2013 11:11

10.5 mm to 9 am in the last two days. No run-off.
Posted by: Seina

Re: Streamflow Observations - 13/11/2013 13:51

For those interested:
It seems the [upper north-eastern quadrant of the] sub-tropical ridge has become a prevailing feature in recent times (days to weeks) across [much of] Southern Australia. From my own point of view it suggests cooler-to-cold days and nights and the possibility of showers. There is evidence present in the literature (Ummenhofer et al. 2009; Evans et al. 2009; Larsen and Nicholls (2009); Risbey et al. (2009); Nicholls, 2010) which could give some indication as to what’s going on relating to this feature.
Posted by: Seina

Re: Streamflow Observations - 18/11/2013 15:39

A moderate flood warning has been issued by the Bureau of Meteorology for the Paterson and Williams Rivers on the Mid North New South Wales Coast at 1:42 pm EDT on Monday 18 November 2013. It is said an average of 170 mm has fallen in the 28 hours to 1 pm today. The Bureau also made a note about how predictable further river rises in the region may be due to rainfall uncertainty.

The River Height for Paterson River at Gostwyck Bridge (station 61349) rose from approximately 1.19 to 11.57 metres between 23:15 pm EDT yesterday (17th) and 14:45 pm EDT today. Major Flood Level is 12.20 metres.

See the NSW flood warnings for more information.
Posted by: Seina

Re: Streamflow Observations - 25/11/2013 13:29

The prior event (previous post) remained at moderate flood level although water levels continued to rise for some time within that flood class.

------------------------------
*[The following is opinion based on observations and publicly accessible computer models]*

Written 24th of November 2013 [Updated from the 21st]:
At this stage there may be a potentially significant rain event pending by the end of the month. Timing could be circa 28th, but rainfall is uncertain due to probable changes between now (24th) and then over the passage of an upper-level trough near a surface high-pressure ridge during that time south of the Bight. Yesterday (23rd), both GFS and ACCESS-G mostly agreed on a scenario, however a question remains about likely rainfall totals and how widespread they will be. Based on uncertainties (today), anywhere up to 70 mm, 20-30 might be a reasonable middle ground.

It seems there is potential including pre-event changes in multiple weather variables (based on models mentioned earlier), however despite this, it could still take until the last 12-24 hours.

Update 25th: Dynamics still very similar (ACCESS-G and GFS), now possibly affecting most of Southern Australia. South-eastern states likely to follow. General falls anywhere between 5 to 10 mm and 50 to 70. Moderately humid northerly winds ahead of the change (WZ forecast for South Australia).
Posted by: Seina

Re: Streamflow Observations - 27/11/2013 14:52

Correction to wind direction – transition between now mostly dry northerlies (observatons) and humid southerlies (Bureau forecast) likely over the next 24 hours.
Posted by: Seina

Re: Streamflow Observations - 29/11/2013 13:30

Cool change with 3.4 mm of light rain/drizzle to 6 pm last night (enough to wet the ground). Temperature dropped from 35 to 15 degrees (max to max) - 20 degrees. No run-off; models downgraded in the last 24 hours prior to the change, although the humidity increased. It is conjectural whether any connection can determined between the change in humidity and soil moisture for this one event.
Posted by: Seina

Re: Streamflow Observations - 30/11/2013 18:25

Some December rains may be approaching [according to the Bureau] ... smile .
Posted by: Seina

Re: Streamflow Observations - 03/12/2013 17:47

Written 1st December 2013 (Updated 3rd):

Originally Posted By: -Cosmic- (naz)
Some December rains may be approaching [according to the Bureau] ... smile .

During the last noticeable change [in weather conditions conducive to significant falls] the specific humidity did not appear to reach a threshold which would have made forecast falls more likely (i.e. increased atmospheric water content/vapour pressure and reduced or unchanging barometric pressure)...the models (those mentioned previously, ACCESS-R and G, GFS) now (from what I can tell) indicate a much sharper upper-level trough and broader high-pressure ridge. There could also [likely] be a noticeable change in the [500-1000 mb] thickness (experienced through a temperature difference). In any case the probability of said falls appears to be increased, with rainfall less uncertain, maybe 10-20 mm over the next week for Central Areas (based on WZ’s recent Mount Barker forecast [1st to 3rd]).

The likely impact on streamflow is probably going to be through additional soil moisture – my opinion is it would take something in the order of 20-40 mm in the first 24-48 hours of the next few days (12 pm CDT today forward) to see appreciable run-off. At the moment those sorts of dynamics (i.e. high precipitable water, consistent 80%+ relative humidity (lower-to-middle level moisture), low pressure and a sharp reduction in thickness) just aren’t apparent (although I could be mistaken). This system seems to currently favour intermittent convective activity with sharp moderate-to-heavy rain. If we’re going to get hail, that might be where it comes from; that said, if the thickness continues on its current path (as forecast by ACCESS-R), hail showers might be possible.

This system is also tracking east, which could make the dynamics which unfold after crossing the (Southeast) coasts maybe a bit more interesting.
Posted by: Seina

Re: Streamflow Observations - 08/12/2013 18:52

Possible revision of likely totals to week ending 9th Dec 2013 (20-40 mm) if specific humidity reaches 0.01 kg/kg by early tomorrow morning and diurnal temp range sharpens enough smile . See BoM Adelaide forecast 4.10 pm CDT.
Posted by: Seina

Re: Streamflow Observations - 12/12/2013 18:37

Originally Posted By: -Cosmic- (naz)
Possible revision of likely totals to week ending 9th Dec 2013 (20-40 mm) if specific humidity reaches 0.01 kg/kg by early tomorrow morning and diurnal temp range sharpens enough smile . See BoM Adelaide forecast 4.10 pm CDT.

Probabilities/thresholds not reached. Slight falls recorded - 6 mm total recorded to the 12th (from 8th).
The 5th of December was the last time the minimum temperature dropped to 5 or less.
Posted by: Seina

Re: Streamflow Observations - 17/12/2013 16:35

GFS suggesting the previously-mentioned specific humidity threshold could be reached and exceeded from up to 48 hours from about mid morning on the 20th. Also suggesting precipitable water could reach above 40 mm for a similar period. Interesting times ahead smile .
Posted by: Seina

Re: Streamflow Observations - 19/12/2013 17:02

Based on official forecasts and an interpretation of models:

Originally Posted By: -Cosmic- (naz)
GFS suggesting the previously-mentioned specific humidity threshold could be reached and exceeded from up to 48 hours from about mid morning on the 20th. Also suggesting precipitable water could reach above 40 mm for a similar period. Interesting times ahead smile .

Written 9:35 pm, 18th of December 2013:

Temperature likely to start falling more appreciably Friday afternoon (20th) [GFS, BoM]. Possible falls in the 15-30 mm range could affect soil moisture for the period 20th to 23rd. Thundery showers possible over the Northern Hills in the 24-36 hours prior to the change in temperature [BoM].
Posted by: Seina

Re: Streamflow Observations - 23/12/2013 10:50

Originally Posted By: bd bucketingdown
why is moist air less dense than dry air?

METEOROLOGIST JEFF HABY

The units of density are mass divided by volume (m/V). Density will increase if either mass increases while the volume remains constant or if volume decreases while mass remains constant.

Density of air will vary as the temperature and moisture content in the air varies. When the temperature increases, the higher molecular motion results in an expansion of volume and thus a decrease in density.

The amount of water vapor in the air also effects the density. Water vapor is a relatively light gas when compared to diatomic Oxygen and diatomic Nitrogen. Thus, when water vapor increases, the amount of Oxygen and Nitrogen decrease per unit volume and thus density decreases because mass is decreasing.

The two most abundant elements in the troposphere are Oxygen and Nitrogen. Oxygen has an 16 atomic unit mass while Nitrogen has a 14 atomic units mass. Since both these elements are diatomic in the troposphere (O2 and N2), the atomic mass of diatomic Oxygen is 32 and the diatomic mass of Nitrogen is 28.

Water vapor (H2O) is composed of one Oxygen atom and two Hydrogen atoms. Hydrogen is the lightest element at 1 atomic unit while Oxygen is 16 atomic units. Thus the water vapor atom has an atomic mass of 1 + 1 + 16 = 18 atomic units. At 18 atomic units, water vapor is lighter than diatomic Oxygen (32 units) and diatomic Nitrogen (28 units). Thus at a constant temperature, the more water vapor that displaces the other gases, the less dense that air will become.

You may be familiar with the concept that moist air is less dense than dry air. This is true when both have the same temperature or when the moist air is warmer. Said in another way, air with a greater percentage of water vapor will be less dense than air with a lesser percentage of water vapor at the same temperature. Often people erroneously believe that moist air is denser than dry air because very moist air is more difficult to breathe than dry air.


After doing some research of my own I mostly agree with the quote you presented. I would however be (on my own part) cautious to differentiate between more surface and upper-level pressure features (in the troposphere) as these dynamics may have a significant impact on where the air is less dense or more dense due to humidity or lack thereof.

------------------------------------------------

Written 17th of December 2013 [revision]:
Temperature statistics:
Max: 36; Min: 6. Diurnal Range, DR: 30.
[18th – 39/8 (DR: 31); 19th – 42/12 (DR: 30); 20th – 37/14 (DR: 23).
18th – first time the diurnal range exceeded 30 since the 7th of January. A diurnal range of 2 degrees was recorded on the 9th of this month (16/14).]

Overnight low of zero on the 22nd of November broke an apparently near-linear run of lows hovering around 5 degrees since the 18th of March, including frosts during the winter months when the low dropped below zero degrees.

The variance (trend) in the maximum temperature between approximately early September and now has been gradually increasing – only since the 22nd has the minimum begun to follow.

Update 22nd December (views expressed are opinion and not fact):
As the specific humidity (in kg/kg) and actual vapour pressure (in hPa) have also risen quite sharply since the 22nd [Nov](from about 0.003 kg/kg and 6 hPa to around 0.008 kg/kg and 13 hPa on the 20th [this month]), this seems to imply a greater availability of moisture. The fluctuations in surface barometric pressure (hPa) over the last 4 days (996, 1007, and 999 since) seems to suggest troughs are becoming more prevalent, with lows mostly further south. This appears to support north-west in-feeds of tropical moisture however the nature of the cloud-cover (with mild changes in temperature and pressure) indicates the cyclic trough-like patterns which are prevalent have a high degree of variability (are therefore characteristically not very robust). This variability seems unlikely to support or facilitate significant rainfall activity because the conditions required to sustain such rainfall (whether convective or not) are not in themselves maintained at such a level (above a threshold) for long enough. For this reason I used the words “possible” in my last post, so those criteria are maintained. Only with adequate conditions for long enough (sustained) will this change – this is something higher precipitable water values can support as the temperature is affected by vapour pressure and thus humidity. High-humidity air is facilitated by evaporation.

The partial consequence of the above is a general depletion in stream flow since early September; however the river is still flowing.
Posted by: Seina

Re: Streamflow Observations - 04/01/2014 13:05

3rd January 2014:
During the last couple of days 9.2 mm has fallen (to 9 am this morning). This appears to be a consequence of relatively high precipitable-water (45-50 mm, GFS), lower pressure (990-1000 hPa sfc), lower density (more water molecules in the lower atmosphere and a greater 500-1000 mb thickness, GFS), and a sharpened diurnal temperature range (19/14 just yesterday). The cut-off for the effects of a narrow, moist cloud-band in the wake of TC/Ex TC Christine appeared sharp, with negative dew points over the Northern (Mount Lofty) Ranges, moderate Central Ranges, and higher on the Southern Fleurieu Peninsula (BoM obs). The higher precipitable-water along with the drop in pressure appeared to facilitate greater likelihood of rain (enough to settle the dust). If, in the next 2-3 days, the maximum temperature falls slightly more (from 23 today), this may increase the chances of rain or showers in the wake of recent days, further.

Streamflow now appears to be borderline base-flow (groundwater only).

Update 4th January 2014: little 988 hPa low barrelling northeast in the Bight 00:00 UTC today on the BoM synoptic chart!?
Posted by: Seina

Re: Streamflow Observations - 06/01/2014 15:41

2 mm from the low to add to the 9.2 mm earlier.
Posted by: Seina

Re: Streamflow Observations - 12/01/2014 12:05

Possible shower(s) circa Wednesday 15th of January smile [Adelaide Hills, BoM].
Posted by: Seina

Re: Streamflow Observations - 12/01/2014 12:50

Originally Posted By: -Cosmic- (naz)
Possible shower(s) circa Wednesday 15th of January smile [Adelaide Hills, BoM].

Streamflow is now depleted to the condition where, at various points along the river, there is no flow. With day-time maximum temperatures now well into the lower-to-mid 30s, sometimes approaching 40, and overnight lows starting to rising only slightly in the last 7 to 10 days, this seems to suggest the diurnal range is increasing. However, the dew point temperature and corresponding vapour pressure remain mostly steady.

Given the tendency of the surface pressure to follow a pattern of 5 to 7 days of rising-and-falling, then deepen to a trough or low-pressure system, this seems to lend support to another prevailing phenomenon. The high-pressure ridge near-adjacent the West Coast of Western Australia has been sitting there, near-stationary for some time now (days, if not a week or more, facilitating trough-like and low-pressure conditions along the west coast, conducive to cyclogenesis), and appears forecast to do so for yet another week. To the south-east of this prevailing feature is a zone (for lack of better terminology) in the lower-to-mid Bight conducive to the passage of low-pressure systems or assisting in the formation of tropical in-feeds across the continental interior. These in-feeds also subsequently appear to be blocked [in the east] by another ridge or similar feature extending into the eastern continental interior. If one then follows the pattern of ridging around to the east, there is yet another zone of higher pressure, more subject to change, yet also near-stationary with prevailing trough-like conditions along the east coast. There, south-easterlies are directed onto more northern coasts, with another quite dominant ridge focused on the continental interior [mentioned earlier] directing similar winds inland.

In both cases (ACCESS-G and GFS) the gap down the middle (a zone of some kind) along with the ridge on the east coast and the trough near the west, are facilitating the thickness to move further south. With the possibility of cyclogenesis along the west coast, the intensity of this may affect wind speeds as far south as 30 degrees latitude (leading them to become lighter). As the [500-1000 mb] thickness is proportional to temperature, and the winds along the eastern continental interior allow heat to be drawn inland, losing latent heat along the way, it may be possible, in my view, the region of instability in the Bight may lead a front to interact with a west-coast low (all else remaining the same).

The region of instability, with south-easterlies at the surface [Central Hills], and a much higher zonal thickness across 30 degrees latitude [looking at Wednesday 15th of January] could provide the conditions for a narrow band of precipitable water to drag across from either a low or region of cyclogenesis, or, follow straight down the continental interior. Narrow because the influence of the sea-breeze would have a narrow coastal cut-off. The former scenario seems more likely at the moment.

Although only hypothetical, the consequences of such a phenomenon could be a rapid increase in dew point, and, given the number of days with mostly-clear if-not clear skies in recent times, a change in the pressure vertical velocity to facilitate rapid cloud formation. The likelihood of specific-humidity thresholds being exceeded in also increased with lower summer-time pressures.
Posted by: Seina

Re: Streamflow Observations - 16/01/2014 10:29

5.1 mm 9 am 14th to 9 am 15th from thundery showers/thunderstorms. Enough to wet the ground before it started to evaporate again.
Posted by: Seina

Re: Streamflow Observations - 18/01/2014 11:54

Another 4.9 mm to 9 am this morning, mostly from moderate rain and some sharp downpours. Very welcome change in conditions.
Posted by: Seina

Re: Streamflow Observations - 22/01/2014 21:08

Where no references, views expressed are opinion:

It is likely rain will be developing late afternoon/evening tomorrow (23rd) [BoM, 4.32 pm CDT forecast], setting in in the following 12-24 hours. I would like to see whether a possible emerging trend over the past few years will eventuate, namely:

Written 19th of April 2011 [Environmental Observation, edited for clarity]:
  • More abrupt flooding associated with conditions conducive to heavy rainfall (thundery showers); locally sporadic (e.g. over 500 metres in 5-10 minutes; sultry conditions with a sudden light shower and 500 metres away, no rain/sultry conditions)…sub-tropical “heat waves” – altered prevailing winds (e.g. easterlies and south-easterlies during summer/autumn rather than southerlies or westerlies, or north-westerlies). Floods and sub-tropical “heat waves” could almost go together when there are sultry conditions.
In a recent heatwave (without quotations “”) the 500-1000 mb thickness [volume] did indeed prevail, however because the temperature was very stagnant [and high] the inverse proportionality between volume and pressure probably applied, meaning lower pressure emerged later on during the heatwave [apparent from the Bureau's Nuriootpa daily observations for the period].

Therefore: “Heatwaves” – increase in sensible heat flux associated with convection, troughs and enhanced CAPE in the absence of cloud-cover [increased humidity appears to have the characteristic of inhibiting photosynthetic processes at a given threshold of concentration]:

[Written 16th of January 2014:
NB: with more latent, and particularly sensible heat, retained in the lower atmosphere during a period of higher 500-1000 mb thickness and moderately-low pressure, hence higher temperatures, it seems the opacity of the atmosphere with respect to water-vapour (specifically, the quantity of heat retained per unit convective available potential energy in Joules per Kilogram) is heightened with higher dew point temperatures (witnessed on the 14th into the 15th January 2014). This could have enhanced convection within the short hourly period thunderstorm activity was mostly likely (which seemed very apparent), however it also means evaporation is strong, giving a possible sharp cut-off between the effects of cloud and no cloud.]

Meaning there may be a potential for flooding in the wake of a heatwave. There is, however, no guarantee of this if there is a sharp cut-off of the abovementioned factor under humid sub-tropical conditions.

Minor flooding at this time may require a quick 10-20 mm from a thunderstorm, or 20-40 from a rainband. It is possible [though remote at the moment], but will have to wait and see smile .
Posted by: Seina

Re: Streamflow Observations - 27/01/2014 14:42

At least one of the environmental observations over the last 2-3 years was falsified (in this occasion) in the last week with the idea that flooding might follow heatwave conditions, probably (again, as an observation) due to a relatively dry lower troposphere, and some parameters which were not sufficiently high-enough to provide a mechanism for significant rainfall (23rd – 24th) (e.g. specific humidity, dew point, precipitable water).

N.B.:

A recent drop in surface pressure circa the 16th-17th suggested the possibility the pressure drop acted as a mechanism in a 20-degree temperature drop over the space of a few hours (near the end of a recent heatwave). The trough seemed to affect both the temperature and thickness.
Posted by: Seina

Re: Streamflow Observations - 06/02/2014 17:55

A possible dramatic local increase in the 500-1000 mb thickness (from current values) within the next 1-2 weeks could actually assist the formation of a substantial temperature-pressure gradient across the southeast (ACCESS-G, GFS).
Posted by: Seina

Re: Streamflow Observations - 09/02/2014 13:00

Originally Posted By: -Cosmic- (naz)
A possible dramatic local increase in the 500-1000 mb thickness (from current values) within the next 1-2 weeks could actually assist the formation of a substantial temperature-pressure gradient across the southeast (ACCESS-G, GFS).

Revision from yesterday: two [temperature-pressure] gradients developing in the time frame indicated – one was overnight (a front expected to clip the coast with minor or trace rainfall totals), the other potentially mid next week.

Note-of-benefit: There is (per the model mentioned) an increasing probability the 2nd gradient change will bring with it conditions conducive to a major rainfall event over 2-3, maybe 4 days. The temperature (GFS) is forecast to fall for the period 13th-16th of February from around 40 degrees C to 30, then maybe the mid-20s. This could be quite a contrast from recent shallow falls in temperature. A reasonably low pressure region is also forecast to cross the state from the west-to-north-westerly direction across WA (both models). A recent post this year [in this thread] highlighted the potential consequences [dynamics] of such a hypothetical scenario unfolding, and made reference (in the last paragraph) to the number and frequency of clear- or mostly-clear-sky days. Other GFS parameters (e.g. precipitable water, specific humidity, 500-1000 mb thickness) could be described as either relatively high or excessive for the period in question.

20-40 mm for the period might be a reasonable estimate however depending on how model scenarios unfold over the next week it might be 4 times that. It seems more reasonable to underestimate and be prepared.

The river as dropped significantly below no-flow levels in all places observed.

Gradient change No.1:
Based on ACCESS-R, GFS forecasts (written 7th of February 2014):

Strahan in Tasmania could be due for a significant rainfall event this weekend (compared to the year to date). On the afternoon of Sunday the 9th of February, GFS is forecasting a steep, temporary change in the 500-1000 mb thickness which may lead near-surface air temperatures to fall significantly towards conditions possibly conducive to hail (approaching 10 degrees Celsius from approximately 22-24 with a similarly sharp drop over a period of 24-36 hours from today [revision 9th – 12-24 hours]). This is supported by the ACCESS-R +48 hour forecast (valid 00Z Sunday 9th of February), which suggest[s] a pocket of near-5400 metre thickness approaching from the west coast [9th - less likely!?]. Combined, GFS and ACCESS-R seem suggest 20-40 mm for the period to early on Monday morning. The mean sea-level pressure may also reach 1000 hPa in this region as the low passes. Slight-to-moderate change in runoff may occur.
Posted by: Seina

Re: Streamflow Observations - 10/02/2014 12:15

Originally Posted By: -Cosmic- (naz)
Gradient change No.1:
Based on ACCESS-R, GFS forecasts (written 7th of February 2014):

Strahan in Tasmania could be due for a significant rainfall event this weekend (compared to the year to date). On the afternoon of Sunday the 9th of February, GFS is forecasting a steep, temporary change in the 500-1000 mb thickness which may lead near-surface air temperatures to fall significantly towards conditions possibly conducive to hail (approaching 10 degrees Celsius from approximately 22-24 with a similarly sharp drop over a period of 24-36 hours from today [revision 9th – 12-24 hours]). This is supported by the ACCESS-R +48 hour forecast (valid 00Z Sunday 9th of February), which suggest[s] a pocket of near-5400 metre thickness approaching from the west coast [9th - less likely!?]. Combined, GFS and ACCESS-R seem suggest 20-40 mm for the period to early on Monday morning. The mean sea-level pressure may also reach 1000 hPa in this region as the low passes. Slight-to-moderate change in runoff may occur.

Highest falls were scattered across the state in a range from about 15-20 mm. Minor changes in flow. See BoM website.
Posted by: Seina

Re: Streamflow Observations - 13/02/2014 13:12

Steady moderate-to-heavy rain, 12 mm and climbing smile .

Edit:

Don't know what infiltrating rate the upper soil can handle, but puddles are forming.
Posted by: Seina

Re: Streamflow Observations - 13/02/2014 14:00

Originally Posted By: -Cosmic- (naz)
Steady moderate-to-heavy rain, 12 mm and climbing smile .

Edit:

Don't know what infiltrating rate the upper soil can handle, but puddles are forming.

Estimated rain rate 10 mm/hr at 1 pm.
Posted by: Seina

Re: Streamflow Observations - 14/02/2014 08:15

Over 3 inches [system total] to 7 am and climbing.
Posted by: Seina

Re: Streamflow Observations - 14/02/2014 09:42

94 mm to 9 am since the first rain band - the river is flowing moderately (has risen more than a 1 metre judging from where the river bank is). Is still raining.
Posted by: Seina

Re: Streamflow Observations - 16/02/2014 18:09

[] Indicates correction or additional info.

#1198291 - 10-06-2013 01:37 PM:

Originally Posted By: -Cosmic- (naz)
2nd Temporary Flash-flood Event, Witnessed 31st May 2013, Upper Onkaparinga Catchment [1st in December 2010]:
See #897948 - 13-11-2010 10:19 PM (very similar):

3rd Temporary Flash-flood Event, Witnessed 14th of February 2014, Upper Onkaparinga Catchment:

Gradient change No.2, written 12th of February 2014:

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
A possible dramatic local increase in the 500-1000 mb thickness (from current values) within the next 1-2 weeks could actually assist the formation of a substantial temperature-pressure gradient across the southeast (ACCESS-G, GFS).

Revision from yesterday: two [temperature-pressure] gradients developing in the time frame indicated – one was overnight (a front expected to clip the coast with minor or trace rainfall totals), the other potentially mid next week.

Note-of-benefit: There is (per the model mentioned) an increasing probability the 2nd gradient change will bring with it conditions conducive to a major rainfall event over 2-3, maybe 4 days. The temperature (GFS) is forecast to fall for the period 13th-16th of February from around 40 degrees C to 30, then maybe the mid-20s. This could be quite a contrast from recent shallow falls in temperature. A reasonably low pressure region is also forecast to cross the state from the west-to-north-westerly direction across WA (both models). A recent post this year [in this thread] highlighted the potential consequences [dynamics] of such a hypothetical scenario unfolding, and made reference (in the last paragraph) to the number and frequency of clear- or mostly-clear-sky days. Other GFS parameters (e.g. precipitable water, specific humidity, 500-1000 mb thickness) could be described as either relatively high or excessive for the period in question.

20-40 mm for the period might be a reasonable estimate however depending on how model scenarios unfold over the next week it might be 4 times that. It seems more reasonable to underestimate and be prepared.

The river as dropped significantly below no-flow levels in all places observed.

Precipitable water and thickness have moderated somewhat – specific humidity remains relatively high to excessive for the 2-to-3-day period 13th-15th (GFS). Given the increased cloud-cover today, expecting [maximum] temperatures to be in the 35-to-40-degree range, dropping towards 20-to-25 degrees, 13th-15th, increasing slightly in the following week. Relative humidity staying in the 85-to-95 % range from about Thursday night, with much higher dew points, bordering on or leading to super-saturated conditions. Flooding after about the first 12-24 hours from Thursday night may be a genuine possibility, with in excess of a 50% change in upper soil moisture (GFS). The impression I get is that 20-40 mm may be a conservative estimate given factors such as the higher dew point, sustained relative humidity, orographic effects and a rather higher specific humidity. This does not appear to be a fickle system.

Flood[ing] is likely (my view) with falls of between 50 and 120 mm locally in the 24-36 hours from Thursday night.

-------------------------------------------------------------

Written yesterday (15th) and today (16th):

After checking figures, stream flow reached a flow volume not seen since the 31st of August 2013 – volume up approximately 6.62 fold in magnitude from Wednesday, soil moisture (estimated) changed from ~ 0.18 to 0.247 as a fraction of 1.

129.5 mm to 9 am Saturday morning.

The rain rate lead to moderate surface land run-off (although run-off was clearly visible when it peaked), lower (modelled) soil layers probably being affected (due to the rain rate being on or around 3-4 mm/hour, at times 5-10 mm/hour). Some modelled indicators have suggested moisture reached deeper retention layers of the soil (up to 1 to 1.5 months lagging), however, these effects probably didn’t become apparent until about midday on Friday, as the river started to rise more rapidly (towards approximately 1.5 metres in height, above levels on Wednesday).

Although low-lying areas were slightly affected, soil infiltration was the primary response apparent (meaning more moisture soaked into the ground than ran off paddocks). The actual prior dry and hot-to-very-hot heatwave conditions probably contributed to this situation because the humidity was quite low in the lower atmosphere to begin with (20-30%) before reaching well above 80% sustained on Friday.

I might add that this is the kind of thing that might seem likely after several weeks (not exactly sure how many, but a lot) with mostly clear-sky or near-clear sky days. Evaporation becomes minimal after a while and sensible heat flux takes over because of the lack of moisture anywhere near the surface. The mechanism seems to be a change in humidity in the lower troposphere brought about by advection of copious quantities of moisture. In theory, the higher temperatures prior to this period facilitated this moisture advection (because the atmosphere could hold more of it). Then all is needed is a pressure gradient (change in pressure with time) and the moisture gradually rains out (in this a case a ridge separating a tropical in-feed from frontal activity to the south).

With some land-surface run-off there has also been mild soil erosion in areas (particularly in parts where the soil couldn’t deal with the rain rate). This morning (Sunday) it was apparent, after closer observations of debris heights, that the river reached varying levels depending on topography (between about 1 and 1.5 metres deeper and 1-4 metres wider).

No doubt this is an historical event (not just in the Adelaide Hills), however sometimes (perhaps) it can help to appreciate what actually does happen (in this case mostly to soil moisture, with some run-off) when we move from one extreme to another (in terms of weather conditions), so we might get an idea of how to better manage impacts to the land in the future. While this rain period may not have been the same as in early December 2010 or late May 2013, the outcome was roughly the same.
Posted by: Seina

Re: Streamflow Observations - 18/02/2014 22:04

Written yesterday (17th of February 2014):

Re: Last system/s – also brought what appears to have been a change in the weather pattern; the high-pressure ridge [in the west] appears to have been disrupted.

In the next 2-3 days another gradient change can be seen sweeping across the Southern and some Eastern Regions of the country (evident on ACCESS-R +48 HRS 17th Feb). This time the change is likely to be more in the 500-1000 thickness.

Gradient change No. 3:
It also looks like within 2-3 days Strahan (in Tasmania) will have had another attempt at moderate-to-significant falls.
Posted by: Seina

Re: Streamflow Observations - 26/02/2014 14:42

Written 21st of February 2014:

Originally Posted By: -Cosmic- (naz)
Written yesterday (17th of February 2014):

Re: Last system/s – also brought what appears to have been a change in the weather pattern; the high-pressure ridge [in the west] appears to have been disrupted.

In the next 2-3 days another gradient change can be seen sweeping across the Southern and some Eastern Regions of the country (evident on ACCESS-R +48 HRS 17th Feb). This time the change is likely to be more in the 500-1000 thickness.

Gradient change No. 3:
It also looks like within 2-3 days Strahan (in Tasmania) will have had another attempt at moderate-to-significant falls.

Highest recorded total for gradient change No.3 was 163 mm at Mount Read AWS (Bureau) in the 24 hours to 9 am today; moderate to significant falls. Other falls included 99 mm in the same period at Zeehan Memorial Museum and 84 at South Queenstown. Strahan Airport AWS received 32 mm to 9 am today, however it is unclear whether it was over a 24-hour period or longer.

See report for Tasmania (Bureau), 4.12 pm on Friday, 21 February 2014. Minor falls (< 10 mm) generally recorded locally (Fleurieu Peninsula). Minimal impact on flow (run-off) seems apparent in both regions.

It is also worth noting 280 mm fell in Glencoe at station 35286 in a 24-hour period to 9 am this morning. After assessing weather maps, etc., it appears a trough and tropical connection associated with an in-feed of moisture from a low in Northern Queensland (adjacent a Monsoon Trough Low) contributed to such a significant rainfall period…

In addition an area in North-western and Central Queensland has been experiencing serious drought conditions (see here – link will update).

It could be surmised hot, humid air from the continent interior (tropical continental air) potentially accompanied by tropical maritime air from the north, moved across this region. This movement acted like a wave as trough-like conditions approached the ranges in the east. The increase in momentum of this hot air mass combined with the latent heat from the tropical maritime counterpart facilitated rapid cloud formation. With the aid of orographic effects, and east-to-west winds on the southern flank of the southern-most low, heavy rain was possible (or in this case, actual).

The impact on flow was significant at the Jordan River at Glencoe (Bureau).
Posted by: Seina

Re: Streamflow Observations - 03/03/2014 23:27

Originally Posted By: -Cosmic- (naz)
#1198291 - 10-06-2013 01:37 PM:

Originally Posted By: -Cosmic- (naz)
2nd Temporary Flash-flood Event, Witnessed 31st May 2013, Upper Onkaparinga Catchment [1st in December 2010]:
See #897948 - 13-11-2010 10:19 PM (very similar):

3rd Temporary Flash-flood Event, Witnessed 14th of February 2014, Upper Onkaparinga Catchment:

[…]

No doubt this is an historical event (not just in the Adelaide Hills), however sometimes (perhaps) it can help to appreciate what actually does happen (in this case mostly to soil moisture, with some run-off) when we move from one extreme to another (in terms of weather conditions), so we might get an idea of how to better manage impacts to the land in the future. While this rain period may not have been the same as in early December 2010 or late May 2013, the outcome was roughly the same.

[] Added.

I think it could be said based on observations of GFS model runs from approximately 5-7 days out from the 14th that the specific humidity led the lower atmosphere to become super-saturated; 45 mm was recorded between midnight 14th of February 2014 and 9 am the same day.

The 79.8 mm recorded in the 22 hours 15 minutes to 10:15 pm on Friday the 14th of February 2014 eclipses the previous recent records for a single event of 58.4 mm on the 8th of March 2011, and 57.4 mm recorded on the 18th of February the same year.

Hypothesis - Is Southern Australia becoming more Humid Sub-tropical?

Recent runoff-related weather events and periods across the country (last 1-2 months) seem to imply a message –increased precipitable water reduces atmospheric density and is heavily dependent on cloud-cover for changes in evaporation. In an environment of increased precipitable water facilitated by changes in the Clausius-Clapeyron Equality, we could expect more humid sub-tropical conditions to prevail over Southern Australia.
Posted by: Seina

Re: Streamflow Observations - 15/03/2014 17:29

The chance of light-to-moderate shower activity over the next 24-36 hours across the Greater Adelaide Area (BoM, ACCESS-R). Some showers may be heavier. Diurnal temperature range is set to narrow with a corresponding increase in the specific humidity (GFS) – surface pressure is already around 992 hPa at 4 pm. Possible 10-15 mm in that period smile , and into Monday morning.
Posted by: Seina

Re: Streamflow Observations - 18/03/2014 20:27

For information:

Originally Posted By: -Cosmic- (naz)
Possible 10-15 mm in that period smile , and into Monday morning.

19.1 mm recorded in the 106 hours to 7 pm tonight. Highest recorded total in that period (including falls since 9 am on the 14th) was 39.2 mm at Aldgate in the Adelaide Hills (most 9 am 15th-17th), followed by Lenswood with 38 (BoM).

Moderate local impact on soil moisture is apparent (observed) with no run-off.
Posted by: Seina

Re: Streamflow Observations - 27/03/2014 15:13

The following in an expression of opinion, initially written 25th of March 2014:

Possible moderate changes in surface runoff by Friday morning (28th of March), Central SA. Specific humidity could peak well above 0.01 kg/kg 27th-28th March (morning-to-morning), sustained (GFS). This will gradually ease off during the remainder of the week according to GFS. Other changes of note include a forecast upper-level low (ACCESS-R 500 hPa HGHT/MSLP, THK) expected to move westward affecting (reducing) the 500-1000 millibar thickness to the north of the state (South Australia, ACCESS-R). The pressure (ACCESS-R, GFS) is forecast to gradually (over the forecast period to the 29th) fall, more so the next 24-48 hours (afternoon of 26th).

Significant 100+ mm falls have already been recorded in areas on the east coast – on the 27th, based on ACCESS-R there is the possibility the instability associated with a surface trough and relatively-high atmospheric moisture content could bring moderate-to-significant falls inland of the QLD coast [due, in part, to the upper-level low moving westward] – further significant falls of 50 to 99 mm recorded to 9 am [27th of March] local time in Central Northern NSW and Central Southern QLD [BoM].

In Central and Eastern SA, there seems a possibility of rain with embedded thunderstorm activity and intermittent scattered showers; regional falls of 20-40 mm possible [under intense thunderstorm activity] with these dynamics.

2.6 mm recorded to 9 am locally (2-5 mm Adelaide Hills, tapering off west, BoM) from shower/storm activity.
[Severe Thunderstorm Warning Issued 12:43 pm Thursday, 27 March 2014 for much of SA Mallee, BoM]
Posted by: Seina

Re: Streamflow Observations - 28/03/2014 10:27

Originally Posted By: -Cosmic- (naz)
In Central and Eastern SA, there seems a possibility of rain with embedded thunderstorm activity and intermittent scattered showers; regional falls of 20-40 mm possible [under intense thunderstorm activity] with these dynamics.

The highest gauged 24-hour fall was 30 mm at Mannahill (site 20013) near Yunta to 9 am this morning. Burra (site 21077) also received 18 mm in the same period [BoM].
Posted by: Seina

Re: Streamflow Observations - 28/03/2014 10:53

N.B.: Falls were not actually regional the last 24+ hours in SA but seemed rather isolated.
Posted by: Seina

Re: Streamflow Observations - 06/04/2014 10:59

Expecting rain Tuesday morning into Wednesday (1-2 days) with much higher dew points, increased 500-1000 mb thickness and higher specific humidity combined with a pressure trough. Anywhere between 20-40 mm in that period, possibly more with heavy falls.
Posted by: Seina

Re: Streamflow Observations - 07/04/2014 18:24

Expression of opinion:

Originally Posted By: -Cosmic- (naz)
Expecting rain Tuesday morning into Wednesday (1-2 days) with much higher dew points, increased 500-1000 mb thickness and higher specific humidity combined with a pressure trough. Anywhere between 20-40 mm in that period, possibly more with heavy falls.

Rain and shower periods extended to Friday night. Totals including possible isolated falls of 50-100 mm (4 days).

There is the potential for the lower atmosphere to become super-saturated during this 4-day period (probably more so Wednesday-Thursday night). My view is the diurnal temperature range is going to narrow quite a bit over the next 3-4 days. Given the GFS forecast increase in thickness combined with the mild temperatures, the dew point may sharply increase.

The impact on flow is likely to start with soil moisture, then once a threshold for retention of moisture is reach, the direct contribution to runoff will start (this is not guaranteed, even if likely). Whether there is a further possibility of a flash flooding of the river seems to depend critically on the rain rate. More than 3-4 mm/hour for a few hours at a time may increase this chance [of flash flooding], if this continues on and off and is sustained for several hours. Given the soil has had enough time to absorb the moisture of previous rain and shower periods this year there may also be the chance it will have difficulty absorbing as much moisture as the last major system which led to moderate river flow over 2-3 days [being another factor].

7-10 mm/hour for more than a few hours may bring excessive localised runoff [minor flooding].
Posted by: Seina

Re: Streamflow Observations - 11/04/2014 11:08

Written 9th of April 2014:

A severe weather warning for heavy rainfall issued by the Bureau at 5 pm CST and 7.51 pm CST respectively, with possible flash-flooding in areas affected [thoughts are area of interest Peterborough to Burra to Eudunda].

Written 10th of April 2014:

Area indicated was affected overnight by falls in the 25 to 49 mm range. Very heavy falls further to the north-west around Coober Pedy (115 mm in the last 24 hours, BoM). Unfortunately no stream gauges are apparent in that area. However it is noted that at Neales R Algebuckina WH (DEWNR) the water level rose by about 1.64 metres between 5.30 am local time on the 8th and 3.45 pm CST. Also of note Warrenbayne in north-eastern Victoria record 59 mm in the 24 hours to 9 am this morning, and an additional 51 since [12+ hours]. 13.3 mm recorded to 3 pm CST today locally here in the Adelaide Hills since the 7th.
Posted by: Seina

Re: Streamflow Observations - 11/04/2014 23:09

http://www.bom.gov.au/cgi-bin/wrap_fwo.pl?IDQ20700.html
Posted by: Seina

Re: Streamflow Observations - 28/04/2014 20:31

The soil is drying out, as is the river; 0 degrees Celsius record overnight 24th-25th April 2014; over a month earlier than last year [2013] (specifically the 17th of June). However the significant falls recorded between the 13th and 16th of February [this year] probably mean there is more moisture in the catchment system than there otherwise would be. Seems there is also something more on the way, with GFS forecasting a substantial increase in specific humidity circa tomorrow morning smile and a corresponding fall in the air pressure. Expecting moderate falls (i.e. 10-20 mm [BoM], higher isolated totals).
Posted by: Seina

Re: Streamflow Observations - 30/04/2014 18:35

Originally Posted By: -Cosmic- (naz)
The soil is drying out, as is the river; 0 degrees Celsius record overnight 24th-25th April 2014; over a month earlier than last year [2013] (specifically the 17th of June). However the significant falls recorded between the 13th and 16th of February [this year] probably mean there is more moisture in the catchment system than there otherwise would be. Seems there is also something more on the way, with GFS forecasting a substantial increase in specific humidity circa tomorrow morning smile and a corresponding fall in the air pressure. Expecting moderate falls (i.e. 10-20 mm [BoM], higher isolated totals).

18.9 mm in the 24 hours to midnight 30th of April, greater falls northwest, south and southeast of SA Central District [BoM]. No visual impact on streamflow as yet, though more showers/rain expected in coming few days [BoM].
Posted by: Seina

Re: Streamflow Observations - 01/05/2014 19:40

Chance of hail with thunderstorms and/or sleet or rain with showers with the next system (due this afternoon/tonight). Falls in a similar range to previous, possibly more on higher peaks with orographic effects or shower streams. Thickness on GFS forecast going into significant decline.*

* N.B. A rainband or showers with significant pressure gradient may clip or even slam into southern coasts overnight [update: incl. Central District]. This could increase the chance of larger rainfall totals.

From the Bureau [Mount Lofty Ranges Area]: Forecast issued at 4:28 pm CST on Thursday 1 May 2014:

Friday: “Cloudy. Showers, widespread and possibly heavy at times till evening. Isolated thunderstorms. Possible small hail from the early morning.”

Potentially heavy line of shower/rain activity noted approaching on the radar 19:00 CST.
Posted by: Seina

Re: Streamflow Observations - 02/05/2014 12:37

To clarify, in my view the current weather passing over Central South Australia is unlikely to generate [moderate] runoff let alone moderate river flow unless something more dramatic changes in the forecast dynamics over the period to the 8th of May. Some soil moisture will be replenished.
Posted by: Seina

Re: Streamflow Observations - 29/05/2014 18:41

[], () – Indicates updates.

The last system to cross SA replenished some soil moisture, up to 40 mm in 48 hours in places, with minor changes in stream flow [BoM]. To that extent the changes in flow may not have been unexpected given falls earlier in the year. This is and was supported by model runs GFS forecast (00Z23may2014), and ACCESS-R forecasts (1000EST26may2014) and (2200EST26may2014).

A second system/cut-off low [due by about Friday afternoon (ACCESS-R 2200EST28may2014), buoyed by the passage of the first given the displacement of the sub-tropical ridge] may bring a further 20 mm to regions already affected by the first. The timing of these systems suggests the latter may bring more significant stream rises if totals exceed 20 mm.

Both systems have been suggested by GFS and ACCESS since the 26th [or at a bare minimum plausible].
Posted by: Seina

Re: Streamflow Observations - 01/06/2014 21:04

11.1 mm of misty drizzle, drizzle and light-to-moderate rain since Friday afternoon (to 9 am this morning). No runoff just rain/drizzle that soaked straight into the soil, or contributed to an already-humid lower atmosphere.

Completely overcast conditions all yesterday - not once did the Sun come out. Very dull, grey sky, with a diurnal temperature difference of 2 degrees (Max: 12, Min: 10). This, in part at least, could be attributed to the fall in 1000-500 thickness as forecast by GFS in the 2-3 days leading up to the passage of this system across SA.
Posted by: Seina

Re: Streamflow Observations - 23/06/2014 17:52

Update for morning of 23rd of June 2014:

After 31.6 mm in the 14.5 hours to 12 pm (midday), the local river has visibly started flowing. Day-time temperature has bottomed out below 10 C.

Still raining (light-to-heavy) at 5:15 pm ACST. Occasional bursts of hail since 12 pm. High winds.
Posted by: Seina

Re: Streamflow Observations - 28/06/2014 11:58

Moderate stream rises along the Onkaparinga River after 25-35 mm fell in the 24 hours to 9 am this morning (Bureau).
Posted by: Seina

Re: Streamflow Observations - 07/07/2014 21:37

Originally Posted By: -Cosmic- (naz)
Moderate stream rises along the Onkaparinga River after 25-35 mm fell in the 24 hours to 9 am this morning (Bureau).

In Addition:

Hypothesis – Higher Probability of a Colder Winter Outbreak for Southeast Australia by the End of June 2014, into Early July, Observation Based

[Edited for clarity]

Written Monday, 16th of June 2014, updates where indicated:

As I understand, recent observable shifts in sub-polar rossby-wave [low] activity suggest the ridging (which is currently disrupted in the Southeast) is leading to an increase in the passage of troughs and sharper pressure gradients [across the Bight]. The lower atmospheric volume (due to a reduction in day-time maxima, and increase in dew points) also appears to be affecting these pressure gradients, and encouraging moist off-shore Southern Ocean wind currents from the Southwest. This further seems to be inducing orographic lifting and cloud-cover further inland. Calmer more stable conditions over the Southwest (near Perth) may follow suit as the recent zonal sub-tropical and sub-polar 200 hPa wind currents become more meridional (Bureau, update 17th – front crossing the SW WA coast). The fact that, for the past week or so, near-zero, zero, or sub-zero minima have (for the most part) declined in frequency also seems to support a case [for] higher dew points and more cloud-cover.

Changes near Perth may affect rossby-wave activity in the east through the current zonal [West-East] continental high-pressure system shifting to meridional [North-South], allowing sharper pressure gradients (associated with strong fronts or cut-off lows) to move further east.

Rainfall for the this time of year (June) is well below average, with less than 30 mm recorded to date (17th), in a month that can average between 90 and 120 mm.

Update 18th (Wednesday) – mostly clear skies from mid-afternoon suggest minima are falling again (0 degrees C, 17th to 18th), and thus dew points.

Update 19th (Thursday) – model outputs GFS/ACCESS-G +96 HRS MSLP, THK, PRECIP 1000 EST Monday 23rd of June 2014 appear to suggest that as slow cut-off lows become less prevalent and a meridional pattern [of lows] starts to develop more robustly in the Southern-Ocean sub-polar region, there is an increasing likelihood of a strong cold front (or two) reaching the Southeast Quadrant [of Australia]. This could mean possible falls of 20-40 mm over a 2-3 day period (in some places more), with a further increase in totals over a period of up to a week. Sometime around the 23rd of June, GFS (19th) is implying the 1000-500 mb thickness will fall sharply during the day, possibly generating temperatures well below 10 degrees C (at this early stage, a solid 3 days out). This implies freezing rain or even sleet. My impression is the meridional sub-polar pattern [jet] needs to become firmly established for this to be possible at low altitude (0-400 m).

Update 20th (Friday) – [there is a] slight change in the ACCESS/GFS outputs, scenarios mostly maintained per previous description; 1000-500 mb thickness still possible sharp decline. At this stage I’d be expecting moderate rain with some heavier bursts and embedded instability [CAPE in latest GFS runs does not seem significant, however this does not rule out embedded thunderstorms along a pre-frontal trough]. Wind speed will undoubtedly be a factor with the system likely to traverse the Southeast Australia rather quickly (both models). As the thickness reduces more, moisture can be moved into a region to facilitate lower pressure, although strong NW winds ahead of a trough could generate fickle conditions until a pressure gradient becomes more prevalent.

The key to this system [starting the 23rd] being robust, in my view, and actually generating 20-40 mm or more in the respective regions (south of 30 degrees latitude) is a synchronicity between the westerly belt [a short-wave upper-level low] and the sub-tropical 200 hPa winds. The GFS +72 HRS sfc PWAT, VVEL 700 hPa implies this is likely, the VVEL turning strongly negative, favouring pre-frontal thunderstorm activity (20th and 21st, GFS). According to GFS’s 06z run, 21st of June, the thickness is likely to plummet to somewhere between 5370 to 5340 metres [NOAA], which probably seems enough for hail at elevation (0-1000 m). CAPE has remained similar.

I would think there could be a significant change in soil moisture with slight-to-moderate change in surface runoff if the forecast dynamics hold [assuming the rain rate does not outpace infiltration], with the [second] front currently crossing SW WA (21st). With the amount of cloud-cover around as this change approaches, I do not think it would be unexpected if the evaporation rate fell markedly during the 23rd.

GFS (22nd of June) indicates the approaching system here is not supported by either higher specific humidity or precipitable water, however the vertical component of the 200 hPa winds is getting quite strong with increased CAPE and instability ahead of strong surface winds [likely to occur around Central SA area ~23rd]. My further impression is this is a thunderstorm-type system.

Update 22nd (Sunday) – Changes in stream flow have been mostly borderline or slight since autumn; would be expecting 15-20 mm overnight from the approaching system, 5-10 mm over the following 2-3 days, tapering off to 1-5 by Thursday, system total 25-50 mm by Thursday; more widespread south of 30 degrees latitude. I would think there could be a moderate-to-significant change in soil moisture, and slight-to-moderate change in run-off.

Update 24th (Tuesday) – 69.1 mm 10 pm 22nd to 3.10 pm 25th June; the system has effectively generated more rain than expected. Temperature max: 8, min: 4.

Update 25th (Wednesday) – It seems apparent [at this stage] there is a chance of a colder more robust event circa the 27th of June, with the long-wave surface rossby-wave pattern rotating to anchor the westerly belt [over the coming 7 days] into synchronicity with tandem upper-level lows [situated North-South, south of the Bight, ACCESS-G]. This meaning the 3 main upper-level lows over Antarctica on the Bureau’s 200 hPa wind and direction forecasts have drifted east and west from the Indian and Pacific Oceans Respectively. If this system (the lower-latitude upper-level low with a front) reaches the Southeast, it is possible additional falls of 20-40 mm could be recorded in Central SA on Friday afternoon [ACST]. The change in thickness during the morning (GFS shows something like 150-200 metres, NOAA) may signal a dramatic fall in the day-time temperature from perhaps 12-13 degrees C to 3-4 degrees C (based on recent observations). The impact on stream flow could start to become more noticeable after 10-15 mm with moderate stream rises in addition to the moderate rises already observed on Tuesday (24th).

Another front [following the events ~23rd, in a steady sub-tropical, meridional phase] overnight (25th-26th) seems likely to generate drizzle and light rain, falls of 1-5 mm already recorded in places [Bureau].

Update 28th – Another 31.1 mm to 9 am with moderate stream rises overnight, no flooding; moisture is still soaking in, implying the rain rate was in excess of the infiltration rate. A GFS forecast run circa the 22nd of June suggested this could happen. The temperature yesterday averaged around 7 degrees C and didn’t really go much lower (~6-8 degrees C).

Update 29th – A further 1.5 mm to 9 am brings the system total (27th to 29th) to 32.6 mm, and the monthly total to 139.8 (above average). Our annual total is now 438.5 (update 1st July), which is more than half the annual average (approx. 840-860 mm).

Update 3rd July (Thursday) – In the last few days (30th June – 2nd July) the day-time minima have again fallen to near zero degrees. With this in mind as the maxima remain mostly steady (the barometric pressure rising), it appears (after consecutive systems between the 20th and 30th with significant pressure gradients) there is a much stronger case for a change (increase) in evaporation rates circa the 8th to 9th of July (GFS/ACCESS-G +144 HRS). This may be similar to what occurred 27th-28th of June. Less cloud-cover (particularly low- and middle-level) seems more likely on the 7th or 8th (or both), the thickness falling to well below the 5400 metres required for hail at sea-level (GFS). [My view is] hail is probably highly-likely with a greater chance of frosts in the initial days before rain falls (as the relative humidity plummets).

The system circa 8th-9th of July seems unlikely to have elevated CAPE. The sub-polar jet could become a more noticeable factor [Bureau Interactive 200 hPa winds] as cold, moist maritime air is drawn up from the south. In my view (3rd of July), rainfall may be anywhere from 50 to 70 mm at the lower end of the range, up to 120 mm by the following Friday [11th of July, widespread through the Adelaide Hills and higher ground along coastal areas]; impacts on flow [runoff] in the moderate-to-significant range. The diurnal temperature range is likely to narrow by the 9th [GFS, 3rd].

Update 4th July (Friday) – Little apparent change in the GFS [NOAA/WZ]. This system (8th-9th of July) does not seem supported by higher precipitable water or pressure vertical velocity (and associated CAPE). It appears thoroughly in the westerly belt with a contribution [on the Bureau’s interactive maps] from both the sub-tropical and (to a lesser extent) sub-polar 200 hPa winds.

Update 6th July (Sunday) – 3 mm recorded 12 am to 5.50 pm ACST (4th July), with another 3 to 9 pm, and 7.1 to 10 am on the 6th – monthly total stands at 13.1. There may be significant rainfall within the next 1-2 weeks.

Update 7th July (Monday) – Little change, perhaps a greater chance of getting very cold maxima over the next week compared to the last 2-3 [GFS, NOAA]. Flood Watch issued by the Bureau noted 5:13 pm ACST. Conditions may be very cold with higher dew points in general across elevated ground near the coast in the Southeast on or around the 11th.
Posted by: Seina

Re: Streamflow Observations - 09/07/2014 10:26

37.5 mm overnight (5 pm to 9 am), river level has reached the river bank in places -- moderate increase in flow. Flood Warning issued by the Bureau for the area with more rain expected today.
Posted by: Seina

Re: Streamflow Observations - 09/07/2014 19:46

Lenswood rainfall site is offline.
Posted by: Seina

Re: Streamflow Observations - 09/07/2014 23:49

River is starting to rise, again, somewhat similar to last night. Another 10.8 mm, 9 am to 11 pm CST. Sporadic heavy showers with some hail on-off. River water level might approach previous peak quicker at this rate eek . Ground underfoot is saturated with large puddles.
Posted by: Seina

Re: Streamflow Observations - 10/07/2014 20:03

Originally Posted By: -Cosmic- (naz)
River is starting to rise, again, somewhat similar to last night. Another 10.8 mm, 9 am to 11 pm CST. Sporadic heavy showers with some hail on-off. River water level might approach previous peak quicker at this rate eek . Ground underfoot is saturated with large puddles.

54 mm to 9 am this morning. Another moderate rise in the river level to just below the peak of the previous peak (8th-9th) smile .
Posted by: Seina

Re: Streamflow Observations - 15/07/2014 17:33

In my view [15th of July], there is the potential for a significant change in run-off circa Thursday morning (17th of July), in excess of 50 mm. Temperatures following this rain [period] may drop well below average [GFS].
Posted by: Seina

Re: Streamflow Observations - 17/07/2014 19:03

Originally Posted By: -Cosmic- (naz)
In my view [15th of July], there is the potential for a significant change in run-off circa Thursday morning (17th of July), in excess of 50 mm. Temperatures following this rain [period] may drop well below average [GFS].

Cracked 100 mm for the month last night at 8.30 pm CST (100.8 mm after 14 mm in 3.5 hours). Another mm to 9 am followed by 12 to 5 pm, giving 113.8 mm to 5 pm, ground is saturated with deep puddles in some areas.
Posted by: Seina

Re: Streamflow Observations - 19/07/2014 22:39

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
In my view [15th of July], there is the potential for a significant change in run-off circa Thursday morning (17th of July), in excess of 50 mm. Temperatures following this rain [period] may drop well below average [GFS].

Cracked 100 mm for the month last night at 8.30 pm CST (100.8 mm after 14 mm in 3.5 hours). Another mm to 9 am followed by 12 to 5 pm, giving 113.8 mm to 5 pm, ground is saturated with deep puddles in some areas.

2 moderate increases in [local Onkaparinga] streamflow between Wednesday the 16th and Friday the 18th of July 2014.
Posted by: Seina

Re: Streamflow Observations - 24/07/2014 19:17

Written 1:15 pm CST, 23rd of July 2014:

Another potentially-significant change in flow seems possible overnight into Thursday morning with a sharp increase in the relative humidity likely within 24 hours, accompanied by a moderate fall in the barometric pressure (GFS).

Update 8:25 pm CST, 23rd of July 2014: Soaking rain approaching 10 mm since approx. 4 pm. 0.9 recorded this morning since 12 am.

Update 6:45 pm CST, 24th of July 2014: [local] river has been rising moderately having exceeded 30 mm for the event.
Posted by: Seina

Re: Streamflow Observations - 01/08/2014 16:23

Another 2 moderate increases in flow between the 29th of July 2014 and today. River is yet to flood [break its banks] so far this year; rainfall has not lasted long enough at great-enough intensity.
Posted by: Seina

Re: Streamflow Observations - 24/09/2014 21:50

An area somewhere between Benalla and Seymour in Victoria based on recent GFS runs (00z and 06z respectively, 24th of September) may see as much as 50-60 mm over the next 24-48 hours, with possibly significant changes in soil moisture and direct run-off. The 06z run indicates up to 0.9 to 1.1 kg/m2 direct surface run-off. 1 kg/m2 is around 1 mm of water covering a square metre.

The local dew point in this region may incline overnight if it is not already doing so.
Posted by: Seina

Re: Streamflow Observations - 25/09/2014 23:34

Originally Posted By: -Cosmic- (naz)
An area somewhere between Benalla and Seymour in Victoria based on recent GFS runs (00z and 06z respectively, 24th of September) may see as much as 50-60 mm over the next 24-48 hours, with possibly significant changes in soil moisture and direct run-off. The 06z run indicates up to 0.9 to 1.1 kg/m2 direct surface run-off. 1 kg/m2 is around 1 mm of water covering a square metre.

The local dew point in this region may incline overnight if it is not already doing so.

Highest falls recorded in the region were to the west of Seymour and east of Benalla (e.g. 81 mm in the 24 hours to 9 am at Rochester [BoM site 80049], 53 mm in the same period at Barnawartha [BoM site 82000]).

61 mm recorded in the same timeframe at Strathfieldsaye [BoM site 581018] east of Bendigo. There was a small change in stream flow [a peak] at Tallangatta Creek at McCallums.
Posted by: Seina

Re: Streamflow Observations - 12/10/2014 14:59

The following is opinion based on model outputs;
There appears to be an increasing likelihood (GFS) of greater than 40 mm in the Wagga Wagga area over the next 24-48 hours facilitated by the passage of a frontal system across the Bight towards Tasmania. Trough-like conditions are likely form (or have already done so) across south-west NSW and north-east VIC. This is may lead to a significant increase in dew points indicating higher relative humidity and precipitable water. The associated pressure gradients will probably sharpen in the next 24 hours across the affected region with the possibility of flash flooding by Tuesday morning.
Posted by: Seina

Re: Streamflow Observations - 14/10/2014 10:39

Originally Posted By: -Cosmic- (naz)
The following is opinion based on model outputs;
There appears to be an increasing likelihood (GFS) of greater than 40 mm in the Wagga Wagga area over the next 24-48 hours facilitated by the passage of a frontal system across the Bight towards Tasmania. Trough-like conditions are likely form (or have already done so) across south-west NSW and north-east VIC. This is may lead to a significant increase in dew points indicating higher relative humidity and precipitable water. The associated pressure gradients will probably sharpen in the next 24 hours across the affected region with the possibility of flash flooding by Tuesday morning.

Falls of greater than 50 mm recorded further east in the Cann and Genoa Region -- slight change in flow apparent [Bureau].

Edit: Highest apparent falls in Southeast NSW.
Posted by: Seina

Re: Streamflow Observations - 26/10/2014 00:09

The following is opinion based on local observations and computer model outputs:
Increasing likelihood of inland upper ridge / temperature displacement – possible effect on stream flow across South-eastern Australia with significant troughs and/or north-west cloud-bands; possible moderate-to-significant rain early-to-mid November smile .
Posted by: Seina

Re: Streamflow Observations - 30/10/2014 18:30

Originally Posted By: -Cosmic- (naz)
The following is opinion based on local observations and computer model outputs:
Increasing likelihood of inland upper ridge / temperature displacement – possible effect on stream flow across South-eastern Australia with significant troughs and/or north-west cloud-bands; possible moderate-to-significant rain early-to-mid November smile .

Written 16th of October 2014 [modifications]:
In summary, observationally, there may be a chance the MJO [Madden-Julian Oscillation] over the tropics to the north is contributing to the development and redevelopment of a thickness and/or [500 hPa] higher-pressure anomaly in that region [near Broome, through the formation and reformation of multiple higher-pressure cells along the Equator], affecting the transition of 200 hPa sub-tropical winds [by leading them to become shallower], which in turn is affecting the generation of north-west cloud-bands. The next couple of weeks are, in my view at this stage [16th], likely to be fine with fickle, intermittent periods of instability conducive to thunderstorm activity, that is 16th to 30th of October 2014, which may be extended to the 3rd or 4th of November. Rains possible during the period after the 3rd or 4th may see a rise in the dewpoint and fall or moderation in both the day-time maximum and night-time minimum temperature – whether rainfall reaches the 20-40 mm range remains to be seen.
Posted by: Seina

Re: Streamflow Observations - 31/10/2014 18:08

Surface barometric pressure has decided to venture south (currently 990 hPa @ ~ 5.30 pm ACDT) smile .
Posted by: Seina

Re: Streamflow Observations - 01/11/2014 12:13

2.3 mm of moderate rain 10 pm 31st Oct to 9 am 1st Nov 2014.
Posted by: Seina

Re: Streamflow Observations - 07/11/2014 22:35

After 3rd-4th of November - 4-5 mm (output from experimental model) possible overnight tonight to 9 am tomorrow.
Posted by: Seina

Re: Streamflow Observations - 09/11/2014 14:30

Originally Posted By: -Cosmic- (naz)
After 3rd-4th of November - 4-5 mm (output from experimental model) possible overnight tonight to 9 am tomorrow.

Difference between the actual and forecast maximum and minimum was too great - no rainfall recorded. Model may have also been inaccurate.

Negligible impact on soil moisture / near-surface humidity – stream flow continues to remain stagnant / in decline.

13th of November – Next time the thickness / 500 hPa feature seems likely to be displaced enough for the south-westerly rossby-wave.

Longer-term change in displacement of 500 hPa feature near Kimberly / Broome is taking a while. Maybe upper low at 500 hPa nearing Perth around that time could become more dominant as forecast [ACCESS-G +144 HRS]? Who knows?

One thing that seems not good for Central QLD dry conditions / Northwest NSW - the near-surface winds seem to reverse from south-easterly to north-westerly by the 14th, then some impact / relief from the south-westerly change by 15th.

For Information Only:
Displacement of Thickness / Upper-Ridge [500 hPa] feature over Broome / Kimberly Region and Possible link to the Passage of Troughs and Frontal Systems – Higher Humidity – Across the Southeast:
TH / UR5: Thickness / Upper-Ridge 500 hPa.
T / UL5: Trough / Upper-Low 500 hPa.
SHSE: Surface High / Southeast.

Model Observations:

=> The observation that on both the ACCESS-G and GFS model runs during the latter period of October, a higher-pressure / thickness feature was situated with a peak upper-high over the Broome / Kimberly in Northern WA.

=> North-westerly winds off the western flank of the TH / UR5 all the way to the Tasmanian west coast. The TH / UR5 seemed to have a range (peak) between about Broome and Central-western NSW. In combination with this feature a T / UL5 appeared to form off the coast of Perth, contributing to maximum wind speed near Geraldton.

=> The uniform absence of the both these [500 hPa] features suggested dominant rossby-wave activity from the Southern Ocean and greater likelihood of significant rain (depending on the shape of the TH / UR5 and T / UL5 on the ACCESS-G and GFS charts). Their prevalence suggests dominant [near-surface] NW / SE winds across the continental interior and troughing along the west coast.

=> During 2-3 days of escalating strength and then dissipation of the TH / UR5 feature there can be a near-surface high-pressure area over the Southeast, directing south easterlies inland, generating lower-humidity and higher-temperature conditions across Central QLD and parts of inland NT / SA, which are evident on the ACCESS-G and GFS Screen Temperature, Dewpoint and Wind Prognoses.
Posted by: teckert

Re: Streamflow Observations - 09/11/2014 22:32

thoughts on possible rain event Fri-Sat? Models starting to look good...
Posted by: Seina

Re: Streamflow Observations - 10/11/2014 00:52

Originally Posted By: teckert
thoughts on possible rain event Fri-Sat? Models starting to look good...

The latest ERM (Empirical Rainfall Model) test suggested 20 to 30 mm moderate rain across Southeast smile . Areas affected by infeed could see more.
Posted by: Seina

Re: Streamflow Observations - 16/11/2014 20:12

Originally Posted By: -Cosmic- (naz)
Originally Posted By: teckert
thoughts on possible rain event Fri-Sat? Models starting to look good...

The latest ERM (Empirical Rainfall Model) test suggested 20 to 30 mm moderate rain across Southeast smile . Areas affected by infeed could see more.

Bold - Highest falls 9 am 15th to 9 am 16th of November recorded in South-Central and North-eastern regions of Victoria/South-eastern NSW. Falls of 25 to 49 mm, some higher (50+ mm) [Bureau].

Locally (Adelaide Hills) highest fall was 27 mm at Cromer Rd. site in the same time smile .
Posted by: Seina

Re: Streamflow Observations - 22/11/2014 12:39

We may actually see a 10 mm+ 24-hour rainfall total for the first time since the end of July today smile .
Posted by: Seina

Re: Streamflow Observations - 22/11/2014 15:50

Originally Posted By: -Cosmic- (naz)
We may actually see a 10 mm+ 24-hour rainfall total for the first time since the end of July today smile .

Past 11 mm and climbing with each passing downpour. Lots of thunder and lightning since approx. 10 am local time. Slight surface run-off with intense rain rates smile . Temps in low 20s and very still.
Posted by: Seina

Re: Streamflow Observations - 23/11/2014 16:25

12.5 mm to 7 pm CDT yesterday (less than 24 hours). The dew point is on the rise from a week or so ago. ~ 40% RH and 29 degrees C around midday.
Posted by: Seina

Re: Streamflow Observations - 01/12/2014 22:06

Opinion based on Observations of Models:

Written 29th and 30th of November 2014 [Updates where indicated and in these brackets].

Potentially Severe Weather Period with Intense Rainfall:
GFS is indicating on or around the 5th to 6th of December this year that there is a chance of excessive rainfall (somewhere ~20 and 80 mm in the space of 24-48 hours) near Mount Stapylton [or slightly further west] (+ 144 hours out) – within 150 km west of the radar position. Surface winds seem to be from the north-northwest, coming off the ocean with higher dew points veering across from the Equatorial Pacific. 500 hPa winds clearly show a higher-pressure region over North-western WA, a relatively small upper-high north of NZ, and a lower-pressure area approaching the East Coast across the Bight. CAPE in the (forecast) affected region is at 1800-2000 J/kg, with a potentially extended period (per dates) of higher dewpoints and a disrupted diurnal cycle [?]. Flooding seems possible with periods of rain. ACCESS-G is supportive at + 168 hours out on the Saturday morning. The southern flank of the NW WA 500 hPa high may assist the upper low moving east towards Tasmania to increase the [precipitable-water] gradient along the coast near Mount Stapylton further, generating slow-moving dense cloud with embedded thunderstorms. The wind gradient is likely to be sharper closer to the upper-low approaching the east coast of Tasmania. [The two main sources of moisture appear to be off the coast from the northerly stream and in a band from the Gulf of Carpentaria].

Note Benefit: over a week out.
Update 30th of November:

More rain expected (70-80+ mm) with higher CAPE. Some localised 100+ mm (1-2 days).

Update 1st of December:

Shifted slightly west and north (Urbenville and Brisbane areas). The period leading up to the 5th or 6th suggests increasing chances of storm activity to the west [Bureau].

Upper divergence noted on the ACCESS-G 300 hPa prognosis (meaning convergence nearer the surface) [+ 120 HRS], possibly associated with smaller upper-high north of NZ. These dynamics do not appear to be breaking down in a hurry.
Posted by: Seina

Re: Streamflow Observations - 02/12/2014 21:23

Current forecast for Stanthorpe, QLD (4:21 pm EST today) [Bureau].

Friday 5th of December 2014: Max/Min 28/17 C.
"Moderate (60%) chance of showers during the day, increasing to high (80%) chance of rain during the evening. A thunderstorm likely."

Saturday 6th of December 2014: Max/Min 26/17 C.
"Very high (90%) chance of rain in the morning. High (80%) chance of showers in the afternoon."
Posted by: Seina

Re: Streamflow Observations - 02/12/2014 21:41

Note-of-Benefit: ERM (Empirical Rainfall Model) output for overnight into tomorrow locally (Adelaide Hills) is approx. 7-9 mm, contributing the soil moisture. Under a thunderstorm, perhaps 10-15 mm. Run-off probably requires rain rate to exceed 7-9 in less than 2 hours.
Posted by: Seina

Re: Streamflow Observations - 04/12/2014 17:30

Originally Posted By: -Cosmic- (naz)
Note-of-Benefit: ERM (Empirical Rainfall Model) output for overnight into tomorrow locally (Adelaide Hills) is approx. 7-9 mm, contributing the soil moisture. Under a thunderstorm, perhaps 10-15 mm. Run-off probably requires rain rate to exceed 7-9 in less than 2 hours.

[Thunderstorm] activity drifted out further east with developing troughs ... possibly increasing the risk of flash flooding in Central-Northern and North-eastern Victoria.
Posted by: Seina

Re: Streamflow Observations - 04/12/2014 18:28

Originally Posted By: -Cosmic- (naz)
Current forecast for Stanthorpe, QLD (4:21 pm EST today) [Bureau].

Friday 5th of December 2014: Max/Min 28/17 C.
"Moderate (60%) chance of showers during the day, increasing to high (80%) chance of rain during the evening. A thunderstorm likely."

Saturday 6th of December 2014: Max/Min 26/17 C.
"Very high (90%) chance of rain in the morning. High (80%) chance of showers in the afternoon."

Please follow official Bureau forecasts and warnings in this period smile ! This is my opinion. The period of impact of this forecast significant weather may be greater than just 24-48 hours.
Posted by: Seina

Re: Streamflow Observations - 07/12/2014 13:42

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Note-of-Benefit: ERM (Empirical Rainfall Model) output for overnight into tomorrow locally (Adelaide Hills) is approx. 7-9 mm, contributing the soil moisture. Under a thunderstorm, perhaps 10-15 mm. Run-off probably requires rain rate to exceed 7-9 in less than 2 hours.

[Thunderstorm] activity drifted out further east with developing troughs ... possibly increasing the risk of flash flooding in Central-Northern and North-eastern Victoria.

Flooding risk increased...Minor Flood Warnings in place for Snowy and Buchan Rivers [Bureau].
[Issued at 1:20 pm EDT on Sunday 7 December 2014]
Posted by: Seina

Re: Streamflow Observations - 09/12/2014 20:37

Moderate river flooding in Central-Eastern VIC yesterday morning.
Posted by: Seina

Re: Streamflow Observations - 10/12/2014 18:43

If GFS has its way [valid today], the temperature profile 11th-13th will be significantly disrupted for the Brisbane area!
Posted by: Seina

Re: Streamflow Observations - 11/12/2014 16:20

Originally Posted By: -Cosmic- (naz)
If GFS has its way [valid today], the temperature profile 11th-13th will be significantly disrupted for the Brisbane area!

Bureau:

INITIAL FLOOD WATCH FOR PARTS OF SOUTH EAST QUEENSLAND
Issued at 1:58 pm EST on Thursday 11 December 2014.

Flood Watches and Warnings current for other states - eastern areas.
Posted by: Seina

Re: Streamflow Observations - 13/12/2014 15:34

13th of December 2014:

Several +100 mm falls have been recorded overnight to 9 am this morning (12th) in the Fitzroy and Kolan River Basins near Gladstone [Bureau]; some exceeding 150 mm. Thought to be due to the influences of surface trough out to sea and the upper-level low to the west, forcing falls to be more north east of the QLD / NSW border [my view]. Relatively small impact on streams observed [Bureau], which to me means a whole lot more could fall before there is flooding.

A second storm front approached the coastal fringes from inland yesterday afternoon (again, 12th) into the evening however because of the north-eastern motion of the wind and moisture features, rainfall appeared to be distributed more uniformly along the coast rather than in a few specific local regions.
Posted by: Seina

Re: Streamflow Observations - 16/12/2014 00:24

River Heights for Dawson River at Knebworth (QLD) showed it reached a moderate flood level of 12.64 metres at 15/12/2014 00:00 local time [Bureau].
Posted by: Seina

Re: Streamflow Observations - 20/12/2014 12:27

#1245515 - 03-03-2014 11:27 PM:

Originally Posted By: -Cosmic- (naz)
Hypothesis - Is Southern Australia becoming more Humid Sub-tropical?

Recent runoff-related weather events and periods across the country (last 1-2 months) seem to imply a message –increased precipitable water reduces atmospheric density and is heavily dependent on cloud-cover for changes in evaporation. In an environment of increased precipitable water facilitated by changes in the Clausius-Clapeyron Equality, we could expect more humid sub-tropical conditions to prevail over Southern Australia.

The key concepts are as follows:
  • Clausius-Clapeyron Equation adjusting for changes in water-vapour (precipitable-water and humidity) content of troposphere.
  • Sunlight has the energy to break water bonds to form water-vapour.
  • Evaporation (and transpiration) increasing humidity.
  • Threshold for humidity lowers latent heat flux and inhibits further evaporation (reversal and break down of the Clausius-Clapeyron).
  • Threshold for break down possibly lowering with time as cloud-cover and sunlight equilibrate.
  • Linearly in break down (higher latitudes), exponential nature (lower latitudes).
  • Soils moisture affected directly by humidity through pore spaces (acts like a sponge).
  • Sponge-like nature of soil affects soil density, evaporation, plant root osmotic processes.
  • Higher threshold for soil-moisture retention (due to prevalence of higher humidity).
  • Increasing cloud-cover modulates sunlight and generates pressure sinks (because moist air is less dense) – including over water.
  • Equilibrating of cloud-cover leads latent heat to equilibrate.
  • Dew points rise.
Posted by: Seina

Re: Streamflow Observations - 29/12/2014 23:32


Two notes [bold added]:
Bureau, 10.54 am CDT today for the 2nd, 3rd and 4th of January 2015 in the Adelaide area (max/min):

42/19 => 41/29 – increased dew point, stable temperature. Winds warm-to-hot northerly turning mild-to-cool southerlies (ACCESS-G/GFS). Higher 500-1000 mb thickness from north drifting west-to-east. Latent increasing, sensible heat moderating. Cloud and trough/s forming.

41/29 => 26/17 – latent heat going somewhere (presumably into convection and instability).
Implying a strong moisture followed by a strong temperature gradient. Principal is that only a certain amount of latent heat can be retained by the troposphere at a given temperature – reduce the maximum ambient temperature, and cloud will start to form. CAPE will increase because troughing allows warm, moistening air to rise into the upper troposphere. Evaporation initially increases with solar heating, however becomes subdued as cloud forms. This increases surface winds. The change in maximum temperature is 15 degrees, meaning the air contracts [the thickness]; given on the 4th the maximum is forecast to be 26 degrees (lower than the previous day’s minimum), the relative humidity would increase, having already increased 2nd to 3rd.

Time will tell.
Posted by: Seina

Re: Streamflow Observations - 06/01/2015 21:38

Originally Posted By: -Cosmic- (naz)
Two notes [bold added]:
Bureau, 10.54 am CDT today for the 2nd, 3rd and 4th of January 2015 in the Adelaide area (max/min):

42/19 => 41/29 – increased dew point, stable temperature. Winds warm-to-hot northerly turning mild-to-cool southerlies (ACCESS-G/GFS). Higher 500-1000 mb thickness from north drifting west-to-east. Latent increasing, sensible heat moderating. Cloud and trough/s forming.

41/29 => 26/17 – latent heat going somewhere (presumably into convection and instability).
Implying a strong moisture followed by a strong temperature gradient. Principal is that only a certain amount of latent heat can be retained by the troposphere at a given temperature – reduce the maximum ambient temperature, and cloud will start to form. CAPE will increase because troughing allows warm, moistening air to rise into the upper troposphere. Evaporation initially increases with solar heating, however becomes subdued as cloud forms. This increases surface winds. The change in maximum temperature is 15 degrees, meaning the air contracts [the thickness]; given on the 4th the maximum is forecast to be 26 degrees (lower than the previous day’s minimum), the relative humidity would increase, having already increased 2nd to 3rd.

Time will tell.

Written 3rd of January 2015 [Update 5th]:

The two-fold increase in [relative] humidity mentioned [midday 3rd and morning of the 4th, evident from Nuriootpa’s Observations] headed northeast-wards into troughing related to a tropical low forming on the Northern WA coast (being blocked in the east by north-south winds and possibly higher dewpoints inhibiting evaporation). This low was/is associated with the Monsoon Trough. The passage of weak fronts appears to be assisting the accumulation of moisture [along the SE coastal fringes] for a temperature gradient along this trough region. A third change in relative humidity may be due early Thursday the 8th.

From what I understand the more the lower thickness, higher density related to the passage of a moderate cold front to the south undercuts the higher thickness to the north along the region of trough activity, the more likely convection will be amplified. Subsequent rain may be on and east of the NW-SE axis.

Written 6th of January 2015:

In my view, if (with emphasis on if) the likelihood of this event doesn’t alter much over the next 24-48 hours [that is, by Thursday afternoon], there may be some flooding in Central Inland South Australia (Coober Pedy), Central-Northern and Eastern Victoria (Wangaratta-Beechworth area), lower-elevation Northern Tasmania and Gippsland, by the 10th-11th. The NW-SE axis has shifted about 2.5-5 degrees east since the +216 hour run (~8 days out) of ACCESS-G for 2300 EDT Thursday 8th of January. A tropical low [with the assistance of a southerly front] seems likely to clip the SA coastal fringes on Thursday morning, possibly generating up to 30-40 mm in the Adelaide Hills through humid, convective conditions [see Bureau forecast, Nuriootpa; 4:03 pm CDT today].

Again, in my view, falls of 70 to 100 mm are possible over a 3-4 day period in regions most affected, some higher.
Posted by: teckert

Re: Streamflow Observations - 08/01/2015 12:36

Heading up towards Burra and can see clean towers to the north where cells are now firing
Posted by: Seina

Re: Streamflow Observations - 10/01/2015 12:47

There is not much point in continuing to post in this thread if people are not going to show an active interest in heavy rainfall events or the likelihood of flooding around/affecting different areas of the country. This monologue of trying to get active participation has been getting waring. The reason I started this thread in the first place was to expand discussion/our knowledge base.
Posted by: teckert

Re: Streamflow Observations - 10/01/2015 14:38

Lol.... Naz, people are very interested in these events but generally participate in the relevant threads.
Posted by: Thunderstruck

Re: Streamflow Observations - 10/01/2015 15:10

Keep posting your obs mate, I always do read (and you know me) and take an interest in what is going on, especially when it comes to big rainfalls.

TS cool
Posted by: Seina

Re: Streamflow Observations - 10/01/2015 17:53

Ok perhaps I misinterpreted in some way. I understand your points, that's fair enough smile - I can continue posting, however it will be based mainly around significant weather events or periods. Thanks for your feedback.
Posted by: ozone doug

Re: Streamflow Observations - 10/01/2015 18:27

Yes I read all your posts Cosmic cheers ,I think a lot of people read your posts and maybe we should post here, We seem to discuss it in other threads blush .
Posted by: Seina

Re: Streamflow Observations - 11/01/2015 11:45

Originally Posted By: ozone doug
Yes I read all your posts Cosmic cheers ,I think a lot of people read your posts and maybe we should post here, We seem to discuss it in other threads blush .

I don't have any objections to people posting in relevant state/territory based threads smile ... I've simply put forward this thread as an invite, and perhaps that's what I needed to factor in.
Posted by: Seina

Re: Streamflow Observations - 11/01/2015 14:49

Max/Min: 39/19 to 13/11 over 4 days gives 39.1 mm.
Based on forecast wind direction (east Tuesday morning, Bureau) might get somewhere between 5 and 40 mm by Tuesday morning [11th-13th] (i.e. areas of moderate rain).

Potential week total 80 mm – minor surface run-off, although given the lack of rain since late July last year, that’s probably something.
Posted by: Seina

Re: Streamflow Observations - 14/01/2015 21:33

15.2 mm 12 am 13th to midnight 14th brings weekly total to 54.3 since the 7th, minor surface run-off/puddles.
Posted by: Seina

Re: Streamflow Observations - 18/01/2015 20:51

Originally Posted By: -Cosmic- (naz)
Max/Min: 39/19 to 13/11 over 4 days gives 39.1 mm.
Based on forecast wind direction (east Tuesday morning, Bureau) might get somewhere between 5 and 40 mm by Tuesday morning [11th-13th] (i.e. areas of moderate rain).

Potential week total 80 mm – minor surface run-off, although given the lack of rain since late July last year, that’s probably something.

Bold - The gradual decline in max/min and the diurnal range effectively constituted a change in pattern from what I can tell; it has become more zonal.
Posted by: Seina

Re: Streamflow Observations - 21/01/2015 22:33

Somewhere between Mackay and Carmila on the mid QLD coast is likely to experience rainfall over the next 12-24 hours which will significantly contribute to soil moisture, and then direct surface run-off into local streams. The probability of heavy or excessive rainfall is high [Bureau].
Posted by: Seina

Re: Streamflow Observations - 25/01/2015 16:16

1302133 – 21-01-2015 10:33 PM:

Originally Posted By: -Cosmic- (naz)
Somewhere between Mackay and Carmila on the mid QLD coast is likely to experience rainfall over the next 12-24 hours which will significantly contribute to soil moisture, and then direct surface run-off into local streams. The probability of heavy or excessive rainfall is high [Bureau].

Falls in 48 hours to 9 am [local time] on the 23rd of January near Mackay:
E.g. Pioneer: ~ 100-150 mm; Proserpine: ~ 50-200 mm.

Revision – additional falls further south around Brisbane (e.g. Coolangatta). Widespread heavy falls in this region.

23-01-2015 10:40 PM:

Approximately 48 hours later and the latest river heights for Teviot Bk at Boonah [Bureau] show flood waters approaching major flood level. This [dramatic] change in flow has occurred in less than 12 hours and appears to be very linear. One can only assume this catchment region is now more than saturated. Falls to 9 pm [local time] over the last 36 hours have many sites to the north and south of Brisbane recording 100-250 mm. Several flow sites across QLD have reached minor flood level recently.

The low currently appears to be clipping coastal fringes near Coolangatta, possibly generating more falls of 20-40 mm or so.

[Coolangatta AWS falls 9 pm 23rd to 12 pm 24th: 29.6 mm.]

23-01-2015 11:20 PM:

River height for Teviot Bk at Boonah reached 5.3 metres before beginning to subside.

The Following Day to 9 am:

Highest 24-hour rainfall total [in the Nerang Catchment area] was 287 mm (347 over 48 hours) at Tallebudgera Ck Mouth AL. Coolangatta AWS recorded 231 mm in the same 48-hour period.
Posted by: Roberto

Re: Streamflow Observations - 26/01/2015 05:48

What do you think about this lightnings map? http://lightandmaps.blogspot.com
Posted by: Seina

Re: Streamflow Observations - 01/02/2015 12:05

18th of January 2015:

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Max/Min: 39/19 to 13/11 over 4 days gives 39.1 mm.
Based on forecast wind direction (east Tuesday morning, Bureau) might get somewhere between 5 and 40 mm by Tuesday morning [11th-13th] (i.e. areas of moderate rain).

Potential week total 80 mm – minor surface run-off, although given the lack of rain since late July last year, that’s probably something.

Bold - The gradual decline in max/min and the diurnal range effectively constituted a change in pattern from what I can tell; it has become more zonal.

For information only:

My understanding is the phasic nature of the southern rossby-wave can be a key indicator of what the amplitude of the next passing frontal system is likely to be.

A zonal wind pattern (in Summer) can mean higher-latitude rossby-wave activity, with the development of ridging [south-to-south-easterly winds] over SA, generating light, intermittent shower activity with little or no significant rain, until troughs re-establish. The impact on summer-time temperatures in the south-east quadrant [of the country] can be marked if the winds are polar- or southern-maritime in origin. Based on these dynamics, a stronger zonal pattern brings a risk of severe frontal weather.
Posted by: Seina

Re: Streamflow Observations - 06/02/2015 20:26

Originally Posted By: -Cosmic- (naz)
For information only:

My understanding is the phasic nature of the southern rossby-wave can be a key indicator of what the amplitude of the next passing frontal system is likely to be.

A zonal wind pattern (in Summer) can mean higher-latitude rossby-wave activity, with the development of ridging [south-to-south-easterly winds] over SA, generating light, intermittent shower activity with little or no significant rain, until troughs re-establish. The impact on summer-time temperatures in the south-east quadrant [of the country] can be marked if the winds are polar- or southern-maritime in origin. Based on these dynamics, a stronger zonal pattern brings a risk of severe frontal weather.

An exception to this is the subsidence of tropical continental or tropical maritime air masses across inland Victoria and New South Wales if the southern rossby-wave is split by ridging from the west, generating an upper low. In such a case temperatures may hike to 35-40 degrees C. This upper low can also impact on the thickness [making it shallower].
Posted by: Seina

Re: Streamflow Observations - 07/02/2015 21:34

Trial Independent, Experimental Rainfall Forecast – Period 4 weeks (valid 18th of January to 18th of February 2015).

Based on the changing dynamics of the current zonal pattern across Southern Australia [18th of January 2015], the current lower-probability rainfall period (< 20%) can be expected to shift to an easterly and then northerly wind pattern (across the Southeast Quadrant by week ending 7th of February). There is a chance of increased rainfall probability in this quadrant with ESE winds during the night with a lower temperature profile (15-10 minimum after 35 during the day, circa 11th of February). As winds then shift north-easterly and more northerly, this probability is likely to sharply decline, to be broken by trough activity and a southerly change.
Posted by: Seina

Re: Streamflow Observations - 08/02/2015 20:52

8th of February 2015:
Mulgrave River at Gordonvale near Cairns reached major flood level earlier today [14.40 metres @ 10:59 08/02/2015 local time, before starting to subside], with falls in excess of 300 mm recorded locally (24 hours to 9 am). A major flood warning was issued at 11 am EST by Bureau. The Bureau is also forecasting 95% probability of 60 to 150 mm for the Cairns area tomorrow:

Forecast issued at 4:31 pm EST on Sunday 8 February 2015 [for Monday].

Quote:
Heavy falls exceeding 280 mm possible. Winds southeasterly 20 to 30 km/h becoming light in the late evening.

…with a significant dew point (max/min 29/24).
Bold Added.
Posted by: Seina

Re: Streamflow Observations - 09/02/2015 22:22

Originally Posted By: -Cosmic- (naz)
8th of February 2015:
Mulgrave River at Gordonvale near Cairns reached major flood level earlier today [14.40 metres @ 10:59 08/02/2015 local time, before starting to subside], with falls in excess of 300 mm recorded locally (24 hours to 9 am). A major flood warning was issued at 11 am EST by Bureau. The Bureau is also forecasting 95% probability of 60 to 150 mm for the Cairns area tomorrow:

Forecast issued at 4:31 pm EST on Sunday 8 February 2015 [for Monday].

Quote:
Heavy falls exceeding 280 mm possible. Winds southeasterly 20 to 30 km/h becoming light in the late evening.

…with a significant dew point (max/min 29/24).
Bold Added.

A secondary flow peak was reached [at around 10 am local time] at Gordonvale at minor flood level today, with 99 mm to 9 am, after 282 the previous 24-hours [Bureau]. Higher rainfall totals recorded near Peets Bridge (470, 48 hours).
Posted by: Seina

Re: Streamflow Observations - 10/02/2015 19:27

Just so I’m very clear about this, the trial forecast can involve some ACCESS-G and GFS model run observations as well as in field [where models don’t go out that far]. The trial model is not prognostic, but concurrent. The only variable which is prognostic (for rainfall) is precipitable water at 1 month delay. It can give a rough idea of how far away a change in dew point is.

Originally Posted By: -Cosmic- (naz)
Trial Independent, Experimental Rainfall Forecast – Period 4 weeks (valid 18th of January to 18th of February 2015).
[…]
As winds then shift north-easterly and more northerly, this probability is likely to sharply decline [1], to be broken by trough activity [2] and a southerly change [3].

[] Changed.

This is off ACCESS-G observations:
[1]: Friday, 13th of February (hot to very hot).
[2]: Saturday, 14th of February (trough activity).
[3]: Sunday, 15th of February (southerly change).
[4]: Wednesday, 18th of February (possible second southerly change, with trough activity).
Posted by: Seina

Re: Streamflow Observations - 15/02/2015 14:17

Originally Posted By: -Cosmic- (naz)
This is off ACCESS-G observations:
[1]: Friday, 13th of February (hot to very hot).
[2]: Saturday, 14th of February (trough activity).
[3]: Sunday, 15th of February (southerly change).
[4]: Wednesday, 18th of February (possible second southerly change, with trough activity).

Hot to very hot in northern parts of the quadrant [Adelaide area – 13th and 14th with NNE winds, surface], trough activity in southern parts, higher dew points [Melbourne 14th, with WSW winds 500 hPa]. Some rainfall totals near Melbourne exceeded 50 mm in the 24-hours to 9 am local time [14th].

Southerly change due ~ this afternoon smile .
Posted by: Seina

Re: Streamflow Observations - 17/02/2015 19:16

Possible Sustained/Heavy Rainfall Note for East Coast:

Westward-moving moisture supplies and wind gradients at 850 hPa, which are due to reach the continental interior this week between latitudes of approx. 15 and 30 degrees South on the Bureau’s Interactive Weather model.

Secondary southerly change unlikely tomorrow (forecast trial).
Posted by: Seina

Re: Streamflow Observations - 19/02/2015 22:04

Originally Posted By: -Cosmic- (naz)
Possible Sustained/Heavy Rainfall Note for East Coast:

Westward-moving moisture supplies and wind gradients at 850 hPa, which are due to reach the continental interior this week between latitudes of approx. 15 and 30 degrees South on the Bureau’s Interactive Weather model.

Near/South of Brisbane [Bureau].
Posted by: Seina

Re: Streamflow Observations - 20/02/2015 20:29

Currently checking River Height for Dee R at Wura, and nearby TM sites (rain gauge).
Posted by: Seina

Re: Streamflow Observations - 20/02/2015 23:34

Originally Posted By: -Cosmic- (naz)
Currently checking River Height for Dee R at Wura, and nearby TM sites (rain gauge).

Nearby River Height for Don R at Kingsborough is exceeding Major Flood Level minimum, and continues to climb sharply eek (just hit 20/02/2015 20:20 10.01, major is minimum 7 shocked ) [According to Bureau website].
Posted by: Seina

Re: Streamflow Observations - 21/02/2015 13:34

FYI:

4:15 pm EDT on Thursday 19th of February 2015 Forecast:

Heavy falls (possibly exceeding 530 mm over 3 days) south and west of Brisbane (Bureau). Roughly peaking Friday-Saturday. Moderate (possibly major) flooding possible in area most affected at higher end of range.

Landsborough AL* 455 mm in 48 hours to 9 am this morning, 23 since.
Posted by: Seina

Re: Streamflow Observations - 25/02/2015 16:01

Parts not referenced are opinion:
Written 17th of February 2015:
The cyclonic feature near Darwin seems to be drawing on stronger near-surface winds originating both off the Indonesian Archipelago and from near Geraldton in WA. There also appears to be extensive tropical troughing going geographically across NW WA, which may be contributing to the splitting of the zonal pattern near Perth. That’s seems a long way for moisture to travel with a temperature gradient! The dew points along the NW WA are also relatively high (surface).

Written 22nd of February 2015:
Sometime down the track [in about 1-2 weeks], it is possible the higher dew point, higher thickness region of inland troughing [update: associated with Ex-Tropical Cyclone Lam] will be clipped by the zonal ridging near Perth, bringing greater quantities of Precipitable-Water to the Southern regions of the country.

Written 18th of February 2015:
The easterlies coming from near New Zealand (off a higher-pressure ridge) appear to be assisting the formation of the trough associated with the low in the Coral Sea. A shallow upper-level trough and adjacent surface ridge appear to extend significantly up the east coast, feeding copious amount of moisture from the Far East into the approaching low/TC [?].

4 pm 18th of February 2015 Forecast:

Heavy falls (possibly exceeding 400 mm over 3 days) near Galiwinku, NT.

4:15 pm EDT on Thursday 19th of February 2015 Forecast:

Heavy falls (possibly exceeding 530 mm over 3 days) south and west of Brisbane (Bureau). Roughly peaking Friday-Saturday. Moderate (possibly major) flooding possible in area most affected at higher end of range.

Total Impacts from surface-runoff: unknown. Possible destructive winds and impact on infrastructure upon landfall (Bureau Cyclone Advice).

[Update: impacts on infrastructure from both Lam and Marcia.]

Observations [Bureau]:
Falls [exceeding 430 mm] 9 am 18th to 23nd:
[N.B.: No. of observations in different regions affected by distribution of sites and available data.]

Significant 24-hour fall.
Waterhouse River NT
Diljin Hill* 267 (258 mm in 24 hours, 9 am 20th-21st).

Impacts on Streamflow:
River height for Waterhouse R d/s of Diljin Hill*.
Rose from 1.67 metres to 4.29 at 8:10 am on the 21st.

Mooloolah, QLD
Ewen Maddock Dam AL * 437
Parrearra Weir U/S AL * 454
Golden Beach AL * 479
Landsborough 523
Hume Lane AL* 491
Old Gympie Rd AL * 468
Beerwah AL * 476
Judds Road AL * 493
Glasshouse Mountains AL * 449

Maroochy, QLD
Eumundi TM * 441
Maroochy Intake Weir TM * 462
Cooloolabin Dam AL * 463
Stoney Wharf Road AL * 439
Radar Hill AL * 444

Impacts on Streamflow:
River Height at Home Park * 13.07 [Monday] (major).
River Height at Tiaro 12.2 [Monday] (major).

River Height for Mooloolah R at Palmview:
4.6-5 metres [Friday night] (major). Major is 4.55.

River Height for Burnett R at Ceratodus *
13.5-14 metres [Sunday afternoon] (major). Major is 8.5.

River Height for Coochin Ck at Mawsons Rd:
7-8 metres [Saturday afternoon] (moderate). Major is 8.2.

River Height for Mary R at Gympie:
16.99 metres [Sunday morning] (moderate). Major is 17.

River Height for Mary R at Miva:
14-15 metres [Sunday morning] (moderate). Major is 15.5.

Several Catchments reached Minor Flood Level.

Originally Posted By: -Cosmic- (naz)
18th of January 2015:

A zonal wind pattern (in Summer) can mean higher-latitude rossby-wave activity, with the development of ridging [south-to-south-easterly winds] over SA, generating light, intermittent shower activity with little or no significant rain, until troughs re-establish. The impact on summer-time temperatures in the south-east quadrant [of the country] can be marked if the winds are polar- or southern-maritime in origin. Based on these dynamics, a stronger zonal pattern brings a risk of severe frontal weather.

It seems so long as the [zonal] phase of ridging continues to clip fronts approaching [southeast] coasts, or assists them to reach the coasts, the situation will remain dynamic with lows and troughs meandering across northern areas (i.e. north of 30 degrees south). I think it’s going to take a phase alignment of an upper-low, and a tropical moisture source and something more significant may occur.
Posted by: Seina

Re: Streamflow Observations - 07/03/2015 21:08

Potential Cyclonic Feature developing near the Gulf of Carpentaria may have a significant impact on Cairns’ weather conditions over the next 1-2 weeks [rainfall related]. Potential changes to Monsoon Trough in that region in that time.
Posted by: Seina

Re: Streamflow Observations - 10/03/2015 22:18

Originally Posted By: -Cosmic- (naz)
Potential Cyclonic Feature developing near the Gulf of Carpentaria may have a significant impact on Cairns’ weather conditions over the next 1-2 weeks [rainfall related]. Potential changes to Monsoon Trough in that region in that time.

Possible (likely?) heavy falls north of/near Cairns over the next 2-3 days, rain/showers extending for 3-4 days [Bureau]. Falls during this time may exceed half monthly average for regions affected (my view).
Posted by: Seina

Re: Streamflow Observations - 13/03/2015 22:38

For Information:

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Potential Cyclonic Feature developing near the Gulf of Carpentaria may have a significant impact on Cairns’ weather conditions over the next 1-2 weeks [rainfall related]. Potential changes to Monsoon Trough in that region in that time.

Possible (likely?) heavy falls north of/near Cairns over the next 2-3 days, rain/showers extending for 3-4 days [Bureau]. Falls during this time may exceed half monthly average for regions affected (my view).

Written 11th of March 2015:

318 mm recorded in less than 2 days (since 9 am) at Tully Gorge AL * [QLD]. Further possible heavy rain expected in the next 24-36 hours [Bureau].

Observations, Afternoon of the 12th of March 2015:

Tully R at Bolinda Estate reach minor flood level (3.95 metres @ 04:52, 12th of March 2015). Related falls Tully Gorge AL * 478 mm (215 to 11th and 12th, 9 am, 48 mm since).

Observations, Afternoon of the 13th of March 2015:

Falls Tully Gorge AL * 586 mm and increasing (9am, 11th to since 9 am, 13th [9:22 pm local time]).

Noted on ACCESS-G/GFS +120 and +144 hours [11th of March], now +48 and +72 hours, a cyclonic feature [Tropical Cyclone Pam] moves towards New Zealand (south) and amplifies an upper-trough, thus reducing the thickness in that region (Southern Hemisphere Western Pacific Ocean). Implications for South West WA (cyclonic/ex-cyclonic feature [Olwyn] hugging coastal fringes), and for Southeast with lows/fronts [my view].

Source Bureau [for Perth, Saturday issued 4:40 WST 13th March]:

Quote:
Heavy falls exceeding 60 mm possible. Damaging winds and heavy rain which may lead to flash flooding possible in the morning and afternoon.

Bold Added.
Posted by: Seina

Re: Streamflow Observations - 14/03/2015 19:04

Information on future events within Australia will not be provided unless major flood level is reach and/or exceeded at relevant sites, and sustained for a minimum 12 hours.
Posted by: Seina

Re: Streamflow Observations - 19/03/2015 21:37

Originally Posted By: -Cosmic- (naz)
Information on future events within Australia will not be provided unless major flood level is reach and/or exceeded at relevant sites, and sustained for a minimum 12 hours.

Severe Tropical Cyclone Nathan may satisfy this criteria upon and after landfall.
Posted by: Seina

Re: Streamflow Observations - 22/03/2015 12:31

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Information on future events within Australia will not be provided unless major flood level is reach and/or exceeded at relevant sites, and sustained for a minimum 12 hours.

Severe Tropical Cyclone Nathan may satisfy this criteria upon and after landfall.

Bold - It did not.
Posted by: Seina

Re: Streamflow Observations - 22/03/2015 22:52

Revision:
Originally Posted By: -Cosmic- (naz)
Information on future events within Australia [may] be provided [if a major threshold for significant weather] is reach and/or exceeded at relevant sites, and sustained for a minimum 12 hours.

[] Changed.
Posted by: Seina

Re: Streamflow Observations - 24/03/2015 21:01

Originally Posted By: -Cosmic- (naz)
Noted on ACCESS-G/GFS +120 and +144 hours [11th of March], now +48 and +72 hours, a cyclonic feature [Tropical Cyclone Pam] moves towards New Zealand (south) and amplifies an upper-trough, thus reducing the thickness in that region (Southern Hemisphere Western Pacific Ocean). Implications for South West WA (cyclonic/ex-cyclonic feature [Olwyn] hugging coastal fringes), and for Southeast with lows/fronts [my view].

My view is an upper-trough was amplified somewhat by Severe Tropical Cyclone Pam moving south towards zonal ridging near New Zealand. This reduced the thickness (temperature) up the Eastern Seaboard from approximately Cairns to SE Queensland. As the actual wind gradient coming off the Coral Sea to the East was relatively shallow (the wind stress was lower), less moisture reached coastal regions for orographic uplift, hence less convection and convergence (troughs). Moisture was thus [likely] usurped by Severe Tropical Cyclone Pam in the Far East, and, to a lesser extent, through southerlies off the upper-trough approaching New Zealand.

With the pressure gradient in the south (near New Zealand) being higher (hence increased wind speed and cloud cover) the zonal pattern was prevalent and sustained. The [surface] ridging in the Coral Sea [adjacent Cairns] may have assisted in preventing Severe Tropical Cyclone Nathan from moving further east, due to [sub-tropical] easterlies.

The outcome of all this is the tropical dip in thickness and lighter easterlies across the continental interior have deteriorated due to the stronger zonal pattern.
Posted by: Seina

Re: Streamflow Observations - 03/04/2015 14:31

There may be a possibility of significant weather system/interaction, on or around Monday the 6th of April for Southeast Australia and Alpine Areas. A sharp/strong upper-trough in the wake of a pre-frontal surface trough could cross the Eastern Bight. The first feature may reach Adelaide with cold 500 hPa air (lower pressure) and a pocket of 5400 thickness. The second (pre-frontal surface trough) may possibly reach Tasmania and/or New Zealand in the same time frame. The pre-frontal trough seems due to interact with a thickness anomaly with higher temperature and lower pressure drifting down the East Coast from the Coral Sea. That anomaly brings with it warmer easterlies near/around Sydney (and maybe increased CAPE near that area with orographic effects). The Coral Sea thickness anomaly/low also seems to be a cut-off, heading nearly directly south and intensifying (become more severe). It is possible this feature will leave a lower-pressure path (space between higher-pressure centres), allowing the upper-trough nearing Adelaide to buckle, providing a mechanism for cold, southerly air to interact with warm, moist northerly air off the Pacific.

Prior to the upper-trough buckling, it may have some impact (rainfall-wise) in the Adelaide Hills as an initial trough splits from the main one, bringing with it more cloud cover and an initial surge of colder air.

On the western flank of the Coral Sea low/rossby-wave trough interaction (as it passes near Mt. Gambier) is the possibility of southerlies (polar and southern maritime) being directed towards Adelaide, bringing constant orographic effects with a much higher probability of rain (a thickening cloud deck, constant lifting mechanism, cold air).

This is dependent on: A. a low forming in the Coral Sea (maybe sub-tropics), and B. the 5400 thickness clipping the Adelaide Area from the west.

With respect to the scenario mentioned above, see ACCESS-G/GFS for more info/reference.
Posted by: Seina

Re: Streamflow Observations - 05/04/2015 10:36

Originally Posted By: -Cosmic- (naz)
That anomaly brings with it warmer easterlies near/around Sydney (and maybe increased CAPE near that area with orographic effects).

No exactly, but see recent Weatherzone News for NSW.
Posted by: Seina

Re: Streamflow Observations - 07/04/2015 22:03

Originally Posted By: -Cosmic- (naz)
There may be a possibility of significant weather system/interaction, on or around Monday the 6th of April for Southeast Australia and Alpine Areas. A sharp/strong upper-trough in the wake of a pre-frontal surface trough could cross the Eastern Bight. The first feature may reach Adelaide with cold 500 hPa air (lower pressure) and a pocket of 5400 thickness. The second (pre-frontal surface trough) may possibly reach Tasmania and/or New Zealand in the same time frame. The pre-frontal trough seems due to interact with a thickness anomaly with higher temperature and lower pressure drifting down the East Coast from the Coral Sea. That anomaly brings with it warmer easterlies near/around Sydney (and maybe increased CAPE near that area with orographic effects). The Coral Sea thickness anomaly/low also seems to be a cut-off, heading nearly directly south and intensifying (become more severe). It is possible this feature will leave a lower-pressure path (space between higher-pressure centres), allowing the upper-trough nearing Adelaide to buckle, providing a mechanism for cold, southerly air to interact with warm, moist northerly air off the Pacific.

[…]

On the western flank of the Coral Sea low/rossby-wave trough interaction (as it passes near Mt. Gambier) is the possibility of southerlies (polar and southern maritime) being directed towards Adelaide, bringing constant orographic effects with a much higher probability of rain (a thickening cloud deck, constant lifting mechanism, cold air).

This is dependent on: A. a low forming in the Coral Sea (maybe sub-tropics), and B. the 5400 thickness clipping the Adelaide Area from the west.

[] – See part-quote below.

Maxima for yesterday and today respectively were 14 and 13 degrees C. Yesterday’s maximum occurred in the morning before colder upper (500 hPa) air arrived from south (before 11 am local time). The temperature then proceeded to dive gradually to around 7-8 degrees by 3-4 pm. It then stayed low until around evening when cloud broke up slightly, briefly allowing for evening sun rays.

It seems interesting that the strength of the upper air allowed it to sustain for the time it did adjacent a higher-pressure centre to the immediate west.

Originally Posted By: -Cosmic- (naz)
Prior to the upper-trough buckling, it may have some impact (rainfall-wise) in the Adelaide Hills as an initial trough splits from the main one, bringing with it more cloud cover and an initial surge of colder air.

=> A total of about 11 mm was recorded from an initial rainband at 3-4 am, 6th.

By night (7-9 pm) it was raining again (mostly moderately), with a rain rate of roughly 0.5-1 mm every 10-15 minutes between 9-10 pm. System total 35.3 mm overall. River is not yet flowing, however puddles suggest the rain was enough that it will probably take some to soak in.

Similar or higher totals were recorded in Victorian Alpine areas in the same timeframe (up to 9 am today, Bureau).
Posted by: Seina

Re: Streamflow Observations - 15/04/2015 22:25

Views Written 14th of April 2015 [Updates Today]:

ACCESS-G and GFS show potential for a 700 hPa and 850 hPa influx in relative humidity (above 70%) sometime around Friday-Saturday (overnight into the morning) [Bureau implying it could be earlier] in the vicinity of the Flinders Ranges and Mid-North of SA. A shallow middle-to-upper-level trough at approximately 5780 metres on the 500 hPa Geopotential Heights may drift across Central SA below this region. This looks like a short-wave rossby-wave split-off (NW-SE) from the main trough as a result of lags in wind stress (exchange of kinetic energy between the ocean and atmosphere). This split-off seems related to the trough south of New Zealand. The main 500 hPa rossby-wave is clearly visible on the prognostic charts south of the Bight.

The temperature (due to this shallower trough activity) is unlikely to fall dramatically, and more likely to stabilise [narrower diurnal range]. The preceding few days show a fall in barometric pressure associated with a smaller diurnal temperature range (in that region), and warmer minima. This increase in the minimum temperature can facilitate a higher 1000-500 millibar thickness on the eastern flank of the shallow upper-trough because the zonal pattern [would be] to the south. This initial likelihood of rain does not appear to be associated with the southern rossby-wave in the Bight, but the arcing of that wave north-east provides a mechanism for the ridge [north of it] to affect the movement of moisture across the continental interior. The movement of moisture comes with 700 and 850 hPa winds [from near Geraldton and Broome]. [The barometric pattern is also likely to change (rotate) as the main 500 hPa rossby-wave approaching the Bight rears bringing more rain/showers to Central parts of SA, southern VIC and NSW by early next week].

[Totals may exceed of 30-50 mm, isolated 80 or more north and east of Mid North SA with possible low-lying flooding. The relative humidity at 700 hPa is showing super-saturated conditions on roughly Friday morning; ACCESS-G. This may also be attributable to orographic stream showers in the region].
Posted by: Seina

Re: Streamflow Observations - 17/04/2015 18:17

1324784 - Observed falls exceeding 100 mm with low-lying flooding (CFS).
Posted by: Seina

Re: Streamflow Observations - 19/04/2015 21:37

Originally Posted By: -Cosmic- (naz)
1324784 - Observed falls exceeding 100 mm with low-lying flooding (CFS).

Rain/showers continued this morning after a cold front passed over late yesterday; 29 mm since midnight 16th to 3 pm CST today. The welcoming of breaking rains and change in pattern smile . CFS as in the SA Country Fire Service.
Posted by: Seina

Re: Streamflow Observations - 21/04/2015 21:50

Further 50-100 mm expected around/near Dungog in NSW Hunter Region over next 24 hours if GFS and ACCESS-R are anything to go by. 349 mm in the last 36 hours (Bureau).
Posted by: Seina

Re: Streamflow Observations - 22/04/2015 20:14

Originally Posted By: -Cosmic- (naz)
Further 50-100 mm expected around/near Dungog in NSW Hunter Region over next 24 hours if GFS and ACCESS-R are anything to go by. 349 mm in the last 36 hours (Bureau).

Heavier falls further south. Three streams gauges (Bureau) show major flood level (or higher) in the Hunter Region; Wollombi Bk at Bulga is rising still.
Posted by: Seina

Re: Streamflow Observations - 23/04/2015 22:04

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Further 50-100 mm expected around/near Dungog in NSW Hunter Region over next 24 hours if GFS and ACCESS-R are anything to go by. 349 mm in the last 36 hours (Bureau).

Heavier falls further south. Three streams gauges (Bureau) show major flood level (or higher) in the Hunter Region; Wollombi Bk at Bulga is rising still.

Bold - My goodness...levels off at 23/04/2015 20:15 at 7.22 metres frown shocked , major flood level being minimum 4.6!
Posted by: Seina

Re: Streamflow Observations - 24/04/2015 18:04

Next significant rainfall period expected to reach the Adelaide area will bring contributions to soil moisture with a remote (slight) chance of run-off with heavier showers smile .
Posted by: Seina

Re: Streamflow Observations - 25/04/2015 11:19

Originally Posted By: -Cosmic- (naz)
Next significant rainfall period expected to reach the Adelaide area will bring contributions to soil moisture with a remote (slight) chance of run-off with heavier showers smile .

Very slight change in run-off with 28.4 mm 12 am 24th to 9 am today.
Posted by: Seina

Re: Streamflow Observations - 25/04/2015 16:38

A storm cell/complex has been near-stationary on Yarrawonga Radar for the past half hour or more.
Posted by: Seina

Re: Streamflow Observations - 30/04/2015 17:01

Rainfall totals in the next 24-36 hours from an upper/surface low-thickness feature with easterly in-feed seem likely to be highest near Tweed Heads on the NSW north coast, with falls up to [and exceeding] 400 mm possible and a [greater than] 70% risk of moderate-to-major flooding Friday, Saturday and Sunday [Bureau] – people in areas likely to be affected by this vigorous system complex can follow Flood Warnings/Advices from the Bureau! Last one issued at 10:57 am EST today. Serious consequences have already resulted from similar events on the Eastern Seaboard recently!
Posted by: Seina

Re: Streamflow Observations - 02/05/2015 12:27

Originally Posted By: -Cosmic- (naz)
Rainfall totals in the next 24-36 hours from an upper/surface low-thickness feature with easterly in-feed seem likely to be highest near Tweed Heads on the NSW north coast, with falls up to [and exceeding] 400 mm possible and a [greater than] 70% risk of moderate-to-major flooding Friday, Saturday and Sunday [Bureau] – people in areas likely to be affected by this vigorous system complex can follow Flood Warnings/Advices from the Bureau! Last one issued at 10:57 am EST today. Serious consequences have already resulted from similar events on the Eastern Seaboard recently!

Some rainfall totals exceeding 400 mm. Serious consequences resulted from system!
Posted by: Seina

Re: Streamflow Observations - 11/05/2015 20:26

Views Written yesterday:

Potential sling-shot very cold air at 500 hPa with sub-tropical and polar Jetstream winds converging early Wednesday morning to the southeast of Adelaide. 5320 thickness seems due to clip Adelaide and Southeast. 200 hPa temperatures -44 to -48 degrees C, suggesting strong surface ridging (towards SE QLD). The geopotential height at 500 hPa also has a sharpish arc near Adelaide running north-south to east. Atmosphere seems due to reach very high humidity Tuesday afternoon. Hail, potential cold-air thunderstorms and rainfall totals exceeding 20-30 mm in a short time to Wednesday afternoon from the previous afternoon across Southeast towards Alps, where snow may accumulate.
Posted by: Seina

Re: Streamflow Observations - 18/05/2015 20:47

Written 16th of May 2015 [added 17th, 18th]:

Originally Posted By: -Cosmic- (naz)
Views Written yesterday:

Potential sling-shot very cold air at 500 hPa with sub-tropical and polar Jetstream winds converging early Wednesday morning to the southeast of Adelaide. 5320 thickness seems due to clip Adelaide and Southeast. 200 hPa temperatures -44 to -48 degrees C, suggesting strong surface ridging (towards SE QLD). The geopotential height at 500 hPa also has a sharpish arc near Adelaide running north-south to east. Atmosphere seems due to reach very high humidity Tuesday afternoon. Hail, potential cold-air thunderstorms and rainfall totals exceeding 20-30 mm in a short time to Wednesday afternoon from the previous afternoon across Southeast towards Alps, where snow may accumulate.

20-30+ mm dumped in Southeast [Melbourne Area] in 24-hour period indicated.

Remnants of 500-hPa air over central Australia seem likely to interact with another upper-trough/low approaching SW WA in coming week, enhancing probability of long-wave trough reaching Southeast with thickness plume [from South] disrupting higher pressure activity (current); next [relatively] significant frontal activity due in region circa 2-3 days [18th-20th]. [Effects from] Thickness to the north [tropical 5760 line] seem negligible in this region as it is being blocked by strong ridging.

[Update today 8:15 pm CST – Approaching].
Posted by: Seina

Re: Streamflow Observations - 18/05/2015 21:14

My view is that totals from initial rain (tonight) may exceed 15 mm, more further southeast. Total to 20th may be 20-40 mm smile .
Posted by: Seina

Re: Streamflow Observations - 19/05/2015 17:56

Originally Posted By: -Cosmic- (naz)
Written 16th of May 2015 [added 17th, 18th]:

Originally Posted By: -Cosmic- (naz)
Views Written yesterday:

Potential sling-shot very cold air at 500 hPa with sub-tropical and polar Jetstream winds converging early Wednesday morning to the southeast of Adelaide. 5320 thickness seems due to clip Adelaide and Southeast. 200 hPa temperatures -44 to -48 degrees C, suggesting strong surface ridging (towards SE QLD). The geopotential height at 500 hPa also has a sharpish arc near Adelaide running north-south to east. Atmosphere seems due to reach very high humidity Tuesday afternoon. Hail, potential cold-air thunderstorms and rainfall totals exceeding 20-30 mm in a short time to Wednesday afternoon from the previous afternoon across Southeast towards Alps, where snow may accumulate.

20-30+ mm dumped in Southeast [Melbourne Area] in 24-hour period indicated.

Remnants of 500-hPa air over central Australia seem likely to interact with another upper-trough/low approaching SW WA in coming week, enhancing probability of long-wave trough reaching Southeast with thickness plume [from South] disrupting higher pressure activity (current); next [relatively] significant frontal activity due in region circa 2-3 days [18th-20th]. [Effects from] Thickness to the north [tropical 5760 line] seem negligible in this region as it is being blocked by strong ridging.

[Update today 8:15 pm CST – Approaching].

Originally Posted By: -Cosmic- (naz)
My view is that totals from initial rain (tonight) may exceed 15 mm

Wide-spread falls exceeding 30 mm through Central SA District smile . Minor low-lying puddles where water has not had a chance to soak in.
Posted by: Seina

Re: Streamflow Observations - 29/05/2015 18:18

38 mm recorded, 17th to 22nd of May 2015.

Think the ridging across the continental interior may break up periodically ~ next 0.5-1.5 weeks. Question is where it will break.
Posted by: Seina

Re: Streamflow Observations - 31/05/2015 12:34

Originally Posted By: -Cosmic- (naz)
Think the ridging across the continental interior may break up periodically ~ next 0.5-1.5 weeks. Question is where it will break.

Cancel that - ridging seems far too pronounced [for the Southeast Coast].

Edit: Meridional surfce ridging near QLD, NSW, VIC interior border could lead to unsettled and very cold conditions on the East Coast as a 540 plume nears TAS [adjacent warm SSTs off Sydney's east].

Posted by: Seina

Re: Streamflow Observations - 04/06/2015 21:09

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Think the upper ridging across the continental interior may break up periodically ~ next 0.5-1.5 weeks. Question is where it will break.

Cancel that - upper ridging seems far too pronounced [for the Southeast Coast].

Italics Added.
Posted by: Seina

Re: Streamflow Observations - 09/06/2015 18:15

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Think the upper ridging across the continental interior may break up periodically ~ next 0.5-1.5 weeks. Question is where it will break.

Cancel that - upper ridging seems far too pronounced [for the Southeast Coast].

Italics Added.

On or around the 14th-16th of June this year a plume of 700 hPa-to-surface moisture may venture across the Coral Sea (roughly from the Equator moving south towards Cairns). This is already evident on both longer-term ACCESS and GFS runs. Extensive trough activity though that region (700 hPa-to-surface) triggered by split-off low activity in the Bight may enhance the effects of falling temperatures. The upper rossby-wave pattern appears to become so disrupted in the south that it may actually propel back on itself, reducing the impact of upper ridging.
Posted by: Seina

Re: Streamflow Observations - 13/06/2015 15:23

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Think the upper ridging across the continental interior may break up periodically ~ next 0.5-1.5 weeks. Question is where it will break.

Cancel that - upper ridging seems far too pronounced [for the Southeast Coast].

Italics Added.

On or around the 14th-16th of June this year a plume of 700 hPa-to-surface moisture may venture across the Coral Sea (roughly from the Equator moving south towards Cairns). This is already evident on both longer-term ACCESS and GFS runs. Extensive trough activity though that region (700 hPa-to-surface) triggered by upper split-off low activity in the Bight may enhance the effects of falling temperatures. The upper rossby-wave pattern appears to become so disrupted in the south that it may actually propel back on itself, reducing the impact of upper ridging.

Bold Added.

Surface-to-700 hPa warmer, moist air quite clearly drifting down across the Coral Sea/QLD coasts circa 16th June (ACCESS-G, GFS) as upper ridging moves east into the Pacific. Upper troughing at 500 hPa also moves east from the Bight/WA; temperature falling sharply on the eastern flank with stronger winds. Surface troughing also possible QLD, NSW, VIC border region as a northerly isobaric dip ventures south. Stronger upper trough approaching SA from Bight is riding on upper edge of deeper main rossby-wave to south of Bight, while the 576 thickness line continues to remain well north [tropical]. System, i.e. shorter-wave upper trough + northerly infeed of moisture may have severe weather potential. Upper ridging over surface low (southeast near Portland, VIC) combined with upper trough over cousin surface low (Eyre Peninsula, SA) could have cyclic effect on moisture.

Bottom line is if the 700 hPa-to-surface moisture (with higher temperatures) reaches the Southeast with enough concentration, system can dump its load en route with upper trough influence. There also appears to be some potential for rain through orographic effects near hilly terrain with a broader-scale upper trough directly up the centre of the continental interior in the next 2 days (already evident).

East coast (i.e. Central-South Region) may need to consider impact of severe storms 16th-17th of June with buckling of main southern rossby-wave.

Interesting times smile .
Posted by: Seina

Re: Streamflow Observations - 13/06/2015 15:30

In my view, 20-40 mm may be possible in 3-4 days in areas most affected [probably interior border regions and East Coast].
Posted by: Seina

Re: Streamflow Observations - 14/06/2015 21:18

Mount Crawford SA Observations turned aggressively towards 99% relative humidity since 4 pm with very narrow diurnal range.
Posted by: Seina

Re: Streamflow Observations - 15/06/2015 15:01

Originally Posted By: -Cosmic- (naz)
In my view, 20-40 mm may be possible in 3-4 days in areas most affected [probably interior border regions and East Coast].

Originally Posted By: -Cosmic- (naz)
Mount Crawford SA Observations turned aggressively towards 99% relative humidity since 4 pm with very narrow diurnal range.

If these dynamics [lower pressure, higher dewpoint, narrower diurnal range, excessive humidity] translate east, places like Inverell and Narrabri in NSW could see significant rain [40-60+ mm] in a matter of 1-2 days with an approaching upper trough from the southwest. There could be a significant local rise in the water table and possible stream rises in those areas. While there is no guarantee this will happen, the likelihood appears to be increasing.
Posted by: Seina

Re: Streamflow Observations - 16/06/2015 19:49

Originally Posted By: -Cosmic- (naz)
System, i.e. shorter-wave upper trough + northerly infeed of moisture may have severe weather potential. Upper ridging over surface low (southeast near Portland, VIC) combined with upper trough over cousin surface low (Eyre Peninsula, SA) could have cyclic effect on moisture.

The current synoptic weather map (i.e. 06 UTC Tuesday 16th of June 2015) seems to reflect this quite well. It merely has to drift a little further east and there will be some [more?] impact near the [Great Dividing] Range.
Posted by: Seina

Re: Streamflow Observations - 20/06/2015 20:41

50-to-100 mm falls recorded in 24 hours to 9 am 17th of June 2015 in South-Central QLD and NE NSW.
Posted by: Seina

Re: Streamflow Observations - 21/06/2015 13:01

Observations, ACCESS, GFS, satellite seem to indicate possible risk of flooding SW WA near upper-trough axis/regions of high temperature gradient. Some uncertainty still apparent. This note expires roughly 48 hours from now.
Posted by: Seina

Re: Streamflow Observations - 28/06/2015 19:51

Originally Posted By: -Cosmic- (naz)
Observations, ACCESS, GFS, satellite seem to indicate possible risk of flooding SW WA near upper-trough axis/regions of high temperature gradient. Some uncertainty still apparent. This note expires roughly 48 hours from now.

Falls west to Albany exceeded 50 mm in the 24 hours to 9 am on the 22nd of June. Flood/soil impact unknown.
Posted by: Seina

Re: Streamflow Observations - 05/07/2015 10:33

Red/orange sky in the morning...shepherd's warning [maybe].
Posted by: Seina

Re: Streamflow Observations - 05/07/2015 12:51

Admin/mods might want to clarify what exactly is a banned/unmentionable topic of discussion. Can I mentioned for example temperature in relation to streamflow, or water vapour in relation to temperature in relation to streamflow...or is conversation so restricted through people getting worried about being banned for minor things that it's not worth it anymore?

Feedback much appreciated!
Posted by: Seina

Re: Streamflow Observations - 07/07/2015 23:02

Written 6th of July 2015 (specific date-range added today):
Gradual shifting of the strong ridging north of the Southern-Ocean Rossby-wave seems to be having the effect of permitting only intermittent mechanisms for the Rossby-wave to push further north. This staggering (or shifting) of the higher-pressure regions across the continental interior appears to allow westerly winds to turn back towards the east once over land, reducing their moisture content through an increase in sensible heat. This increase in sensible heat may be attributable to lower thickness across the middle of the country, permitting lower temperature profiles and reducing dewpoints. The thickness [roughly the height to the tropopause] would thus support more middle and higher cloud-cover, enabling the formation of lower-level inversions [and fogs]. The increase in sensible heat may also mean (A) the diurnal range shifts and becomes narrower and (B) reduced evaporation from the surface environment, retaining more soil moisture and surface humidity. The exception to this could be frosts, because the humidity released in the surface environment [as fog] is not sufficient to prevent further energy loss during the night, thus there is radiative cooling.

As the westerlies return to the coasts as drier easterlies [except in the tropics] they are driven into the upper troposphere with the approaching rossby-wave activity, inducing cold-air troughing. This cold-air troughing has much more energy to release in the form of convection than its drier continental counterpart due to latent heat [i.e. from water vapour]. This increases temperature differences and energy gradients through the fact warmer air can sustain more moisture, and generates a mechanism for cold-air thunderstorms. Another factor is energy moves naturally from regions of higher energy to regions of lower energy; it will not spontaneous move from lower to higher. The higher energy with a cool/cold, moist rossby-wave interacting with a cooler, drier easterly is the rossby-wave, because it retains more latent heat [moisture]. Thus the cold-air troughing with northerly wind convergence can see a release of latent heat on or in the wake of the trough region.

The local annual pattern of barometric pressure is such that during summer the pressure is lower, but varies less, while during winter it is higher; however can vary rather a lot. While this is a general pattern, the overall tendency [going deep into winter] seems to be deep-low formation [referring to Southern Australia].

As a result, in my view, there is a chance of moderate rain with cold-air thunderstorms [around the Southeast] in the next 1-2 weeks (more specifically between the 7th and 12th of July) with changes in the southern-ocean rossby-wave pattern smile .
Posted by: Seina

Re: Streamflow Observations - 10/07/2015 19:44

Surface temperatures and forecast dewpoints narrowing somewhere between 6-8 degrees Celsius in the Hills, probably 4-6 Mount Lofty area.

700 hPa relative humidity higher over the same region on Saturday morning, but what is rather telling, if it remains consistent, is the -30 degrees Celsius and lower at 500 hPa rocketing up, with polar winds right through to 300 hPa. Looking forward to possible 50-100 mm in the next week or so, with some hail and possible sleet to add smile .

-4 degrees as an overnight low [with a severe frost] might have been a warning sign [of this] last week, the difference being the minimum temperature going up overnight, and the maximum down.
Posted by: Seina

Re: Streamflow Observations - 10/07/2015 21:20

Originally Posted By: -Cosmic- (naz)
Looking forward to possible 50-100 mm in the next week or so, with some hail and possible sleet to add smile.

Output from Experimental Rainfall Model (Hills, tomorrow), suggesting if the max is anywhere between 8 and 4 degrees, min between 8 and 2, rainfall ~ 24 to 58 mm.
Posted by: Seina

Re: Streamflow Observations - 11/07/2015 12:19

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Looking forward to possible 50-100 mm in the next week or so, with some hail and possible sleet to add smile.

Output from Experimental Rainfall Model (Hills, tomorrow), suggesting if the max is anywhere between 8 and 4 degrees, min between 8 and 2, rainfall ~ 24 to 58 mm.

Totals in the 24 hours to 9 am this morning ranging from ~ 9-10 mm near Callington/Edinburgh AP/Birdwood to 35-40 near Mount Lofty...and the local river is now visibly flowing smile [23.8 since midnight to 10 am].
Posted by: Seina

Re: Streamflow Observations - 12/07/2015 11:39

Possible next cold pool [i.e. well below 540 thickness] seems to be due early-mid this week (Tuesday-Wednesday) [ACCESS-R, GFS].
Posted by: teckert

Re: Streamflow Observations - 12/07/2015 14:33

Originally Posted By: -Cosmic- (naz)
Admin/mods might want to clarify what exactly is a banned/unmentionable topic of discussion. Can I mentioned for example temperature in relation to streamflow, or water vapour in relation to temperature in relation to streamflow...or is conversation so restricted through people getting worried about being banned for minor things that it's not worth it anymore?

Feedback much appreciated!


That should be all okay. As long as you are not specifically referring to climate change. (which i presume you are referring to in regards to banning?)
Posted by: Seina

Re: Streamflow Observations - 12/07/2015 19:13

Originally Posted By: teckert
Originally Posted By: -Cosmic- (naz)
Admin/mods might want to clarify what exactly is a banned/unmentionable topic of discussion. Can I mentioned for example temperature in relation to streamflow, or water vapour in relation to temperature in relation to streamflow...or is conversation so restricted through people getting worried about being banned for minor things that it's not worth it anymore?

Feedback much appreciated!


That should be all okay. As long as you are not specifically referring to climate change. (which i presume you are referring to in regards to banning?)

Thanks for the clarification smile .
Posted by: Seina

Re: Streamflow Observations - 24/07/2015 16:34

Views revised today:
A change in wind direction to mostly north-westerlies and increase in thickness/precipitable-water [from the Indian Ocean] could lead to rain and possible heavy falls, especially across Mid-Central and South-Central NSW within the next 12-36 hours, isolated severe weather [including thunderstorms] possible. Estimated 15-35 mm in the [Adelaide] Hills as a guide.
Posted by: Seina

Re: Streamflow Observations - 25/07/2015 11:11

Originally Posted By: -Cosmic- (naz)
Views revised today:
A change in wind direction to mostly north-westerlies and increase in thickness/precipitable-water [from the Indian Ocean] could lead to rain and possible heavy falls, especially across Mid-Central and South-Central NSW within the next 12-36 hours, isolated severe weather [including thunderstorms] possible.

Highest falls in 24 hours to 9 am this morning in Ovens River Catchment area (Mt. Buffalo ERTS 50 mm). Similar falls in NE NSW/SE QLD - Severn R at Ashford reaching minor flood level in that time.
Posted by: Seina

Re: Streamflow Observations - 25/07/2015 20:44

Originally Posted By: -Cosmic- (naz)
Estimated 15-35 mm in the [Adelaide] Hills as a guide.

A rainband/thunderstorms has/have not occurred in the Hills in the last ~ one and a half days - winds are very strong! Based on tomorrow diurnal temperature profile (Bureau: Max/Min: 11/5) we might get 13.6 mm, however that is not guaranteed.
Posted by: Seina

Re: Streamflow Observations - 27/07/2015 23:14

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Estimated 15-35 mm in the [Adelaide] Hills as a guide.

A rainband/thunderstorms has/have not occurred in the Hills in the last ~ one and a half days - winds are very strong! Based on tomorrow diurnal temperature profile (Bureau: Max/Min: 11/5) we might get 13.6 mm, however that is not guaranteed.

20.9 mm in last 36 hours; 19.5 enough to raise the local river by about 0.4 m (Bureau), with some debris coming from upstream on the 25th-26th.
Posted by: Seina

Re: Streamflow Observations - 01/08/2015 16:02

Rainfall increased enough overnight for the local river flow to get going slightly again smile .
Posted by: Seina

Re: Streamflow Observations - 01/08/2015 20:23

Originally Posted By: -Cosmic- (naz)
Rainfall increased enough overnight for the local river flow to get going slightly again smile .

Flow level may be further impacted overnight with another estimated ~ 7-15 mm.
Posted by: Seina

Re: Streamflow Observations - 02/08/2015 11:17

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Rainfall increased enough overnight for the local river flow to get going slightly again smile .

Flow level may be further impacted overnight with another estimated ~ 7-15 mm.

15 mm recorded near Cudlee Creek overnight. Minimal impact on local flow.
Posted by: Seina

Re: Streamflow Observations - 02/08/2015 22:05

Based on 3+ years of daily data, the South-eastern Australian wet season (winter/spring rains) appear to be starting to get going smile .
Posted by: Seina

Re: Streamflow Observations - 09/08/2015 16:53

Estimated rainfall range, 9th to 12th of August: 27.4 to 93.8 mm; possible minor flooding.
Posted by: Seina

Re: Streamflow Observations - 09/08/2015 17:02

Originally Posted By: -Cosmic- (naz)
Estimated rainfall range, 9th to 12th of August: 27.4 to 93.8 mm; possible minor flooding.

Date, Max/Min (degrees C), Rain (mm), Maximum River Water Level (m)
9th August 2015: 17/5, 2 to 4.7, 0.04
10th August 2015: 12/6, 8.1 to 25.8, 0.11
11th August 2015: 10/6, 12 to 41.7, 0.58
12th August 2015: 12/5, 5.3 to 21.6, 1.09

Temperatures source Bureau.
Posted by: Seina

Re: Streamflow Observations - 09/08/2015 17:13

If the river water level exceeds 0.8 metres, flooding is probable.
Posted by: Seina

Re: Streamflow Observations - 11/08/2015 13:50

Originally Posted By: -Cosmic- (naz)
If the river water level exceeds 0.8 metres, flooding is probable.

0.8 metres has been reached or exceeded in the last 3 years (2012-14). Based on current temperature profile (11/7) could get anything up to 40 mm [overnight] smile .
Posted by: Seina

Re: Streamflow Observations - 11/08/2015 23:10

10:40 pm CST: Local river is starting respond to rainfall (has stopped raining...mostly).
Posted by: duckweather

Re: Streamflow Observations - 12/08/2015 10:06

Hi folks.

I think I have posted this in the right thread?

I came across an article on "The Watchers - by Adonai" regarding the El Nino;

"Odds keep rising for a big El Niño in 2015"

(Just realized this should be in the ENSO thread blush )



Cheers, Duck.
Posted by: Seina

Re: Streamflow Observations - 16/08/2015 20:54

Actual Observations (and Estimates)
Date, Max/Min (degrees C), Rainfall Range and Actual Rain (mm), Predicted and Estimated Maximum River Water Levels (m)
9th August 2015: 16/2, 0.2 to 2 (0.7), 0.04 (0.04). Obs: 0.10.
10th August 2015: 12/7, 11.3 to 30.3 (2.2), 0.11 (0.03). Obs: 0.08.
11th August 2015: 11/7, 14.1 to 40.4 (21.8), 0.58 (0.08). Obs:0.20.
12th August 2015: 11/6, 9.7 to 31.8 (12.4), 1.09 (0.11) Obs: 0.29.
Observations [Bureau] for comparison based on flood level of 0.8 metres
N.B: Streamflow estimates based on 1100+ days of continuous data, so the “memory” of the system is a factor.
*Streamflow fell.
Posted by: Seina

Re: Streamflow Observations - 20/08/2015 22:09

Potentially serious [heavy/widespread] inland/coastal rain event pending mid-to-late August, more details coming.
Posted by: Seina

Re: Streamflow Observations - 21/08/2015 16:44

Centres that may be affected include Albany (WA), Wudinna, Yunta, Hawker and Waikerie (SA), Bombala and Bairnsdale (VIC), Sydney, Wollongong and Mudgee (NSW), and Goondiwindi and Longreach (QLD). Falls between 20 and 60 mm may be possible, and to be honest, I'm no longer that interested in keeping this thread maintained.
Posted by: Seina

Re: Streamflow Observations - 22/08/2015 15:42

Originally Posted By: -Cosmic- (naz)
Centres that may be affected include Albany (WA), Wudinna, Yunta, Hawker and Waikerie (SA), Bombala and Bairnsdale (VIC), Sydney, Wollongong and Mudgee (NSW), and Goondiwindi and Longreach (QLD). Falls between 20 and 60 mm may be possible, and to be honest, I'm no longer that interested in keeping this thread maintained.

Date were [and still are] Saturday 22nd to Monday 24th of August.
Posted by: Seina

Re: Streamflow Observations - 24/08/2015 16:48

Extended to the 27th with severe thunderstorm potential and heavy falls [24-hours to 9 am today, Hunter Region].

FLOOD WATCH FOR ILLAWARRA, SOUTH COAST AND THE LACHLAN AND NEPEAN RIVER VALLEYS

Issued at 12:54 pm EST on Monday 24 August 2015

At this stage there is a greater than 70% chance of flooding in the following river valleys from Tuesday onwards:

1. Lachlan River valley downstream of Wyangala Dam, including the Belubula River - moderate rural flooding

2. Nepean River - minor flooding

3. Illawarra District - moderate to major flooding

4. South Coast - local flash flooding

Severe Weather Warnings are also being issued for this event.
Posted by: Seina

Re: Streamflow Observations - 24/08/2015 22:34

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Centres that may be affected include Albany (WA), Wudinna, Yunta, Hawker and Waikerie (SA), Bombala and Bairnsdale (VIC), Sydney, Wollongong and Mudgee (NSW), and Goondiwindi and Longreach (QLD). Falls between 20 and 60 mm may be possible, and to be honest, I'm no longer that interested in keeping this thread maintained.

Date were [and still are] Saturday 22nd to Monday 24th of August.

And Cairns.
Posted by: Seina

Re: Streamflow Observations - 26/08/2015 13:47

Nowra in NSW on the Shoalhaven River may be in trouble with a moderate flood warning issued by the Bureau early this afternoon, EST.
Posted by: Seina

Re: Streamflow Observations - 05/09/2015 13:11

On track for breaking a streak of years with flows >= 0.8 metres if spring/early-summer is not wetter than at present. Possible a subdued El Nino may assist this if IOD has anything to do with it.
Posted by: Seina

Re: Streamflow Observations - 13/09/2015 11:58

Observed relative humidity took a significant dive in late August this year, to values not seen in records dating back to early-to-mid December 2012...for that time of year following reasonable rainfall in July.

Records are hourly and the change was gradual and very noticeable. This could either be an ominous sign, or a sign of something coming. I think the latter.
Posted by: Seina

Re: Streamflow Observations - 30/09/2015 12:16

Ok Cairns, here we go smile …a wet period could be just around the corner.

For information – “Blip on the Time Line”

The shifting [surface] ridging across the continental interior (generating higher dew-point temperatures along the South-eastern Australian coast [off-shore], accompanied with a change in wind direction, WNW-to-ENE), combined with shifting [upper] troughing across the Eastern Seaboard coastal fringes is and has been leading to showers [isolated-to-scattered] near Mt. Gambier, the NSW Central-to-Lower Coasts, and regionally near Cairns [week ending 26th of September 2015]. If the [NE QLD] upper troughing reaches a critical point [with the 500 hPa southern rossby-wave pushing north-eastwards towards Cairns] the change in temperature seems likely to bring dew-points even higher early-October.
Posted by: Seina

Re: Streamflow Observations - 03/10/2015 20:27

Originally Posted By: teckert
Originally Posted By: -Cosmic- (naz)
Admin/mods might want to clarify what exactly is a banned/unmentionable topic of discussion. Can I mentioned for example temperature in relation to streamflow, or water vapour in relation to temperature in relation to streamflow...or is conversation so restricted through people getting worried about being banned for minor things that it's not worth it anymore?

Feedback much appreciated!


That should be all okay. As long as you are not specifically referring to climate change. (which i presume you are referring to in regards to banning?)

Ok, so I can say this:
I have an idea:

The majority of non-water vapour gases in the atmosphere that have either a temporary or permanent dipole moment contribute to sensible heat flux, which affects the specific and relative humidity of the air, thus impacting on surface soil moisture smile .

And no it's not about banned topics. It's about science.
Posted by: Seina

Re: Streamflow Observations - 08/10/2015 17:45

Originally Posted By: -Cosmic- (naz)
Observed relative humidity took a significant dive in late August this year, to values not seen in records dating back to early-to-mid December 2012...for that time of year following reasonable rainfall in July.

Records are hourly and the change was gradual and very noticeable. This could either be an ominous sign, or a sign of something coming. I think the latter.

A possible approaching synoptic event seems to have 700 hPa winds directing moisture from near Weipa off the northern flank of the easterly belt sourced from the Coral Sea, the remainder from the upper rossby-wave in the south.
Posted by: Seina

Re: Streamflow Observations - 10/10/2015 12:13

Precursor Synoptic Situation
For information only – see if it comes true grin ...
Views Written 7th-8th of October 2015
:
Valid 9th-11th of October 2015:

Roughly September 23rd this year, a surface high was centred just south of Adelaide directing cool-to-cold southerlies and polar maritime air across SA, with frosts in areas most affected. Come the 28th, that high had shifted further south and was reducing the impact of strong westerlies through countering easterlies south of Ceduna, while allowing east coast lows to seemingly penetrate further south (hence showers on the east coast near Sydney). Then, just recently (1st October) the upper rossby-wave took a swing north towards Brisbane (and then Cairns) generating more showers through a combination of variables:

Higher CAPE; Lower/moderated CINH (convective inhibition)
Higher 700 hPa Relative Humidity
Increased Precipitable Water (Tropics)
Lower Lifted Indices
Higher Surface Dew points
Moderated Surface Temperatures

That upper trough, having impacted on the previous high in the Bight, gave ample room for another high to drift further north across the continental interior, north of Adelaide, delivering copious heat and light-to-moderate northerly winds. This brought the opportunity for the high centred in the west to align west-east, and the high in the east to be aligned north-south, allowing trough and front-like activity into the Bight, with a cool change.

This facilitates a wave of higher pressure along about -35 degrees latitudes. The remnants of the upper trough and frontal activity [having passed over the Southeast] linger into another weekend [10th-11th], over Central and Eastern Victoria. These include higher CAPE, some cap (Convective Inhibition), 700 hPa Relative Humidity of 50 to 90%, Lifted Indices of -4 to -6, dewpoints of 16 to 18 (at peak), Precipitable Water of 25 to 35 mm, and surface plus-26-degree temperatures converging from the north with sub-22-degree temperatures from the south with weak upper low formation.

Updated 9th of October 2015:
Lower 500-1000 mb thickness; weak upper low
Surface Toughing – to Immediate West – western slopes of Great Dividing Range
Higher CAPE (1200 to 1400 J/kg); Lower/moderated CINH (convective inhibition precursor)
Higher 700 hPa Relative Humidity (Tropics – Coral Sea, Southern Ocean)
Higher 850 hPa Relative Humidity (Tropics – Coral Sea, low at ~ 7 deg S, 170 deg E)
Increased Precipitable Water (700 hPa-sfc)
Lower Lifted Indices (-2 to -6)
Higher Surface Dew points (14 to 18 deg C, update: same, by Saturday)
Moderated Surface Temperatures (14 to 18 deg C, update: 18 to 24 deg C, by Sunday)

Locations likely to be most affected include Echuca, Kyabram, Tatura, Shepparton, Wangaratta, Yarrawonga, Albury-Wodonga, Benalla, Mt. Hotham, Mt. Buller, Omeo and Falls Creek.

Possible falls in the 20-40 mm range with severe weather/heavy rain (Friday-Sunday).
Severe weather may be possible over the next week (7-10 days from Friday) between Sydney and Brisbane.

[Disclaimer: Not official].
Posted by: Seina

Re: Streamflow Observations - 11/10/2015 16:27

#1343427 - Seems this system has a lot of localised and regional momentum with thunderstorm warnings issued for various areas of VIC and NSW. Perhaps some areas may end up getting 50-80 mm in 48 hours (esp. near the Great Dividing Range).
Posted by: Seina

Re: Streamflow Observations - 18/10/2015 12:20

Notes for Regionally-Significant Rainfall Periods

In 24-48 hours to 12th of October 2015, it seems [the rainfall] primarily resulted from changes to the Clausius-Clapeyron Equality taking place across north-eastern and eastern Victoria. In summary, warmer air can hold moisture, before it precipitates, than colder air. If the atmospheric thickness is reduced (e.g. lower 500-1000 mb thickness) after a higher value, dew points will increase, and this moisture will rain out accordingly.

Highest rainfall totals in the 24 hours to 9 am 11th of October included 60 mm at Crooked River Alert (585033) and 55 mm at Waterford Alert (84118). Omeo received 26, Falls Creek: 44 and Mt. Hotham: 28 [Bureau].

Originally Posted By: -Cosmic- (naz)
For information – “Blip on the Time Line”

The shifting [surface] ridging across the continental interior (generating higher dew-point temperatures along the South-eastern Australian coast [off-shore], accompanied with a change in wind direction, WNW-to-ENE), combined with shifting [upper] troughing across the Eastern Seaboard coastal fringes is and has been leading to showers [isolated-to-scattered] near Mt. Gambier, the NSW Central-to-Lower Coasts, and regionally near Cairns [week ending 26th of September 2015]. If the [NE QLD] upper troughing reaches a critical point [with the 500 hPa southern rossby-wave pushing north-eastwards towards Cairns] the change in temperature seems likely to bring dew-points even higher early-October.

Areas near Cairns/Innisfail (Johnstone River Basin) continued to receive shower activity, recording falls in the 25 to 49 mm range (in the same time frame), more-so on the 10th.

Severe Thunderstorm Warnings were issued for north-Central and Eastern NSW (on the 13th at 3:22, 3:42 and 7:50 pm EDT respectively), which included warnings about large hailstones and possible flash flooding. Whether flash-flooding actually occurred in the area requires evidence (e.g. footage). Despite this, two gauges recorded moderate rainfall totals exceeding 30 mm in 30 minutes between approximately 3 and 4 pm EDT in the affected areas.

Originally Posted By: -Cosmic- (naz)
#1343427 - Seems this system has a lot of localised and regional momentum with thunderstorm warnings issued for various areas of VIC and NSW. Perhaps some areas may end up getting 50-80 mm in 48 hours (esp. near the Great Dividing Range).

It appears only Crooked River and Waterford in the Victorian High Country exceeded 50 mm in the 48 hours to 9 am on the 12th of October. There were also isolated falls of between 50 to 99 mm in the 24 hours to 9 am, 14th of October between Sydney and Brisbane.

17th of October 2015, 10:50 am CDT:

A larger-scale dip in the 500-1000 mb thickness has re-appeared near Broome lately. With the 500 hPa rossby-wave continuing its north-eastward track (with or without impact) from south of Perth, this could reduce distance over which temperature differences occur and generate more unsettled conditions.
Posted by: Seina

Re: Streamflow Observations - 23/10/2015 22:55

Originally Posted By: -Cosmic- (naz)
#1343427 - Seems this system has a lot of localised and regional momentum with thunderstorm warnings issued for various areas of VIC and NSW. Perhaps some areas may end up getting 50-80 mm in 48 hours (esp. near the Great Dividing Range).

Area [Eastern VIC] got hit again 22nd of October. 50-100 mm falls.
Posted by: Seina

Re: Streamflow Observations - 27/10/2015 15:37

Views: Possible period of heavy rainfall leading to localised flooding, occurring in the Brisbane-Tweed Heads border region over the next 24-48 hours. Possible 30-50 mm.
Posted by: Seina

Re: Streamflow Observations - 27/10/2015 16:51

This is official...

-----------------------------------------------

Bureau of Meteorology
TOP PRIORITY FOR IMMEDIATE BROADCAST

SEVERE THUNDERSTORM WARNING - SOUTHEAST QUEENSLAND

for DAMAGING WIND, HEAVY RAINFALL and LARGE HAILSTONES

For people in the Ipswich and parts of the Logan, Somerset, Scenic Rim and Brisbane City Council Areas.

Issued at 3:26 pm Tuesday, 27 October 2015.

The Bureau of Meteorology warns that, at 3:25 pm, severe thunderstorms were detected on weather radar near Harrisville and Peak Crossing. These thunderstorms are moving towards the north. They are forecast to affect Moogerah Dam, Amberley and Rosewood by 3:55 pm and Ipswich, Lake Manchester and Fernvale by 4:25 pm.

Damaging winds, heavy rainfall that may lead to flash flooding and large hailstones are likely.

-----------------------------------------------
Bold Added.
Source: Bureau.
Posted by: Seina

Re: Streamflow Observations - 27/10/2015 17:27

Warning changed 4.10 pm EST.
Posted by: Seina

Re: Streamflow Observations - 29/10/2015 01:09

Originally Posted By: -Cosmic- (naz)
Views: Possible period of heavy rainfall leading to localised flooding, occurring in the Brisbane-Tweed Heads border region over the next 24-48 hours. Possible 30-50 mm.

Coringa AL (SE QLD) 95 mm in 37 hours; rapid local stream response of 3.25 metres in about 8.5 hours (Degilbo Creek).
Posted by: Seina

Re: Streamflow Observations - 29/10/2015 18:30

Looks like it's making the news:

Weatherzone:
Thursday October 29, 2015 - 12:26 EDT
Rain coming to more than 80% of drought-affected Australia

N.B...this is news, if those affected by drought-like conditions want rain, this may be the first glimmer of it smile .
Posted by: Seina

Re: Streamflow Observations - 31/10/2015 17:30

Possible [Flood-Causing] Inland NT/NSW/QLD/VIC – Coastal WA/SA Rain Event
For information only
Views Written 28th of October 2015
:
Valid 31st of October to 3rd of November 2015:

A 500-1000 mb thickness anomaly over Broome [WA] region is slightly fickle. May become more established in coming days [week]. Surface ridging is very pronounced in the NW-SE direction in the Bight, displacing surface low and upper trough activity towards the north and south. Once upper troughs pass by this ridging [west-to-east], there is sometimes enough of a gap for them to intensify, or combine with a surface low, increasing dewpoints. What can tend to happen is a surface low (from more tropical latitudes) can interact with the upper rossby-wave from the south and provide momentum for that wave to have more influence into the Bight. As this occurs, surface ridging takes up to more characteristic shape with a ridge oriented west-east [from Perth to the Bight], and another north-south [near the Tasman Sea]. At the momentum it is more V-shaped with a single, fragmented ridge centrally, preventing the upper rossby-wave influencing coasts.

This NW-SE ridging means the gap between ridge breaks [surface troughs] is smaller, and can be shallower. Thus the upper rossby-wave can clip a surface trough, but not significantly interact bringing isolated light showers and milder temperatures [to SE coasts]. This shallow, milder upper rossby-wave can however ride the upper eastern edge of a surface ridge till it meets a northerly thickness plume, with higher temperatures, and with the surface ridge still NW-SE. Thus southerly or polar maritime air can meet tropical continental air coming off the Great Dividing Range, generating cloud near and off the coast, and a sea-breeze front, with isolated higher-intensity rainfall.

With a surface low forming out in the Indian Ocean and meeting the southern upper rossby-wave by disrupting the NW-SE ridging, winds in the east (NE QLD coasts) can veer more south from Weipa, bringing tropical maritime air to inland QLD/NSW. This then interacts with upper troughing winds pushing up from the Bight. A second low may split off from the main upper rossby-wave following the initial interactions between higher 500-1000 mb thickness and upper troughing [dates below], bringing an upper cut-off through SW WA, to the Bight and SA/VIC. This cut-off cannot move west (higher-pressure ridge) or south (upper trough), therefore it can only move north or east (i.e. directly east).

[Added 30th: CAPE through north-eastern NT [and Broome] areas 24 hours out is forecast to be exceeding at least 2000 J/Kg, with Lifted Indices to -4 to -6. Surface winds are firmly coming off the ocean to the north and the Coral Sea, veering south towards the QLD/NSW border. Dewpoints 18 to 20 C, implying strong convective activity over the next week]

[=> Means now 29th]

CAPE is about 1200-1400 J/Kg => 1600-1800 J/Kg;
LFTX (Lifted Indices) -2 to -4 (even -5/6) => -4 to -6.
Temperatures 24 to 34 => 30 to 32 (Central NSW to border region inland QLD);
Dewpoints 14 to 20 => 16 to 18;

The ETA for first period is about 1st to 4th of November. Time frame for heavy rain possibly 24-48 hours within that; falls in the vicinity of 50-100 mm in inland QLD/NSW do not seem out of the question. ETA for second period partially overlaps first [2nd to 5th], bringing 20-40 mm to the Central-North and Southeast SA.

For those interested, have a look at ACCESS-G, GFS...not because the models are onto something, but because of the dynamics – CAPE, LFTX, 500 hPa winds/temp and dewpoints. The first wave [with rain] can be seen 30th-31st, the second is a little more apparent [2nd-4th].

-----------------------------------

Note 5 pm CDT, 31st of October - Already underway.
Posted by: Seina

Re: Streamflow Observations - 05/11/2015 16:49

Originally Posted By: -Cosmic- (naz)
Thus southerly or polar maritime air can meet tropical continental air coming off the Great Dividing Range, generating cloud near and off the coast, and a sea-breeze front, with isolated higher-intensity rainfall.

50-100 mm reached along the Great Dividing Range in SE NSW/NE VIC, seemingly negligible influence on local flows.

Originally Posted By: -Cosmic- (naz)
ETA for second period partially overlaps first [2nd to 5th], bringing 20-40 mm to the Central-North and Southeast SA.

Fall exceeding 50 mm recorded in the Central North and SA Mallee. Flooding reported.

Isolated falls exceeding 100 mm recorded in NE NSW/SE QLD last 24 hours.
Falls of 50+ mm [in the last week ending today] also recorded in Central NSW, QLD, and near Broome.
Posted by: Seina

Re: Streamflow Observations - 13/11/2015 16:24

My Views: Serious rain/thunderstorm activity probable within the next 4-5 days, ETA by 17th of November; approximately Emerald QLD area; 50-100 mm possible, maybe be in a 24-48 hour deluge.
Posted by: Seina

Re: Streamflow Observations - 16/11/2015 20:31

There has been an increase in the local river water level in the last few days, of maybe half a metre, and the river is actually flowing. No rain has fallen that could explain this.
Posted by: Seina

Re: Streamflow Observations - 17/11/2015 21:42

Originally Posted By: -Cosmic- (naz)
My Views: Serious rain/thunderstorm activity probable within the next 4-5 days, ETA by 17th of November; approximately Emerald QLD area; 50-100 mm possible, maybe be in a 24-48 hour deluge.

Falls of between 50 and 99 mm recorded in the 24 hours to 9 am this morning between Emerald and Brisbane. Possible small changes in flow.
Posted by: Seina

Re: Streamflow Observations - 22/11/2015 21:07

Originally Posted By: -Cosmic- (naz)
My Views: Serious rain/thunderstorm activity probable within the next 4-5 days, ETA by 17th of November; approximately Emerald QLD area; 50-100 mm possible, maybe be in a 24-48 hour deluge.

Written 13th of November:

Axis of shallow upper-level trough hinges on a pronounced ridge of higher-pressure system to the south, direction of movement is ENE towards the coast from inland west of Emerald. Upper trough is slanted WNW-ESE further inland (near border) with 500 hPa winds wrapping around it from the southwest (milder temperatures). Surface trough from the north (tropics) drags higher-dew-point winds across Cairns towards the Great Dividing Range (GDR); CAPE is streaming down the coast. Surface winds are from the ESE towards northern Brisbane and surrounding coasts, keeping temperatures down; may also affect NE NSW GDR area into Tuesday. The surface trough plume is like a slingshot, sending higher-dew-point winds onto SE QLD coasts.

Upper trough, surface ridge, southern rossby-wave slingshot axis is approximately 22-23 degrees South, 150 degrees East. There is a temperature discontinuity there (sharpish gradient), higher temperatures to the NW, lower to the south SE. Consequence is moisture will rain out.
Posted by: Seina

Re: Streamflow Observations - 08/12/2015 15:28

10.9 mm in about an 1 hour very early this morning from consecutive, noisy, bright thunderstorms.
Posted by: Seina

Re: Streamflow Observations - 09/12/2015 21:29

Originally Posted By: -Cosmic- (naz)
10.9 mm in about an 1 hour very early this morning from consecutive, noisy, bright thunderstorms.

All soil moisture (and/or evaporation).
Posted by: Seina

Re: Streamflow Observations - 10/12/2015 22:24

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
10.9 mm in about an 1 hour very early this morning from consecutive, noisy, bright thunderstorms.

All soil moisture (and/or evaporation).

A major factor may have been nocturnal cooling, explained elsewhere on this forum.

http://forum.weatherzone.com.au/ubbthreads.php/topics/909473/Nocturnal_Cooling_in_South_Aus
Posted by: Seina

Re: Streamflow Observations - 12/12/2015 13:51

Somewhere 19th-22nd (Dec '15) potentially increasing to very high probability of rain (Adelaide, Adelaide Hills).
Posted by: Seina

Re: Streamflow Observations - 18/12/2015 15:28

Originally Posted By: -Cosmic- (naz)
Somewhere 19th-22nd (Dec '15) potentially increasing to very high probability of rain (Adelaide, Adelaide Hills).

May see a temperature change of about 15-20 degrees C (or more) on Saturday night.
Posted by: Seina

Re: Streamflow Observations - 23/12/2015 16:02

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Somewhere 19th-22nd (Dec '15) potentially increasing to very high probability of rain (Adelaide, Adelaide Hills).

May see a temperature change of about 15-20 degrees C (or more) on Saturday night.

2.5 mm recorded overnight 19th into 20th (Sunday), then during Sunday.

A trial forecast based on wind directions during the day/night suggests the highest probability of rainfall for the Adelaide area will be from the morning of the 26th to the following day (27th), in the afternoon.

GFS has been consistently indicating (from the date of the last post above) a significant pressure trough will travel down from about Weipa and the GOC towards Cairns, with narrowing diurnal temperature and dew point ranges, and inverse 500-1000 mb thickness and 850-mb temperature gradients – increases in both. The pressure trough enables an accumulation of moisture [streams] with wind direction, the higher temperatures at 850 mb can facilitate more moisture in the atmosphere, and the 500-1000 mb gradient may assist instability near the eastern edge of the GDR.

Conditions seem likely to become sultry and/or humid in that area of the country for the next 3-5 days. Bureau’s Cairns forecast from 4:30 pm AEST on Tuesday 22 December 2015 for today had 28/23 (possible heavy falls, 40 to 80 mm), max/min temperature profile, which illustrates just how much precipitable water is going to hit the coastal fringes. A lower minimum would suggest less precipitable water, but this looks very unlikely.

It is interesting to note a possible heat trough which was (still is?) situated to the east of Geraldton in WA, during the recent SA heatwave. This could have been forcing westerlies to the south off the coast towards Broome, which is where a lot of trough activity is seems to be.

Trial Christmas-Boxing Day Forecast (Adelaide Hills):
Please note temperatures are averages based on a probability range.

December Wind Direction (Time) Rainfall Probability Moisture Max.T Min.T Highest Poss. Rainfall (mm)
22 East-southeast (Night) High (>60%) Tm
22.5 South-southeast (Day) Medium (20-60%) Pm 25 12.5 4.4
23 East-southeast (Night) High (>60%) Tm
23.5 South-southeast (Day) Medium (20-60%) Pm 25 12.5 4.4
24 North-northeast (Night) Medium (20-60%) Tc
24.5 North (Day) Low (<20%) Tc 42.5 12.5 0.1
25 North (Night) Medium (20-60%) Tc
25.5 West-northwest (Day) Low (<20%) Tm 30 12.5 1.9
26 South (Night) High (>60%) Sm + Pm
26.5 South (Day) High (>60%) Sm + Pm 22.5 12.5 6.9
27 East-southeast (Night) High (>60%) Tm
27.5 South-southeast (Day) Medium (20-60%) Pm 25 12.5 4.4
28 East (Night) Medium (20-60%) Tm + Tc
28.5 South (Day) High (>60%) Sm + Pm 22.5 12.5 6.9

This is an area-specific forecast and its precision diminishes dramatically outside the district.

Legend (Air Masses): Season: Summer.
Pm – Polar Maritime.
Tm – Tropical Maritime.
Tc – Tropical Continental.
Sm – Southern Maritime.

Wind Direction Source Weatherzone/BoM Forecast

Disclaimer: no responsibility accepted for use/decisions made on the basis of the above trial.
Posted by: Seina

Re: Streamflow Observations - 24/12/2015 12:16

Falls exceeding 100 mm in the Daintree in the 24 hours to 9 am local time this morning smile .
Posted by: adon

Re: Streamflow Observations - 27/12/2015 14:01

So I have been keeping an eye on the rain echoes over the Warrego river. Just wondering what are the chances of some flows coming from there? Hopefully this will will be a primer for a bigger event coming down from the Gulf.
Posted by: Seina

Re: Streamflow Observations - 27/12/2015 21:37

Originally Posted By: adon
So I have been keeping an eye on the rain echoes over the Warrego river. Just wondering what are the chances of some flows coming from there? Hopefully this will will be a primer for a bigger event coming down from the Gulf.

If the low affects areas around Boulia enough, for long, there could [and I emphasise could] be flows down the QLD streams of the Warrego Basin, into NSW [maybe even down into SA’s far northeast] … but I would think the rains would have to be sustained, and at times heavy, around the New Year smile . I just waited for another model run of GFS to pass, and low-and-behold, the area of highest precipitation for the low around the 31st changed! We basically need to save every run from here till the 31st to get a “track map” or average for the highest probability of where and when rain in that NT/QLD/SA border region will fall [if it does].
Posted by: adon

Re: Streamflow Observations - 27/12/2015 22:08

It looks like some sort of force field(feeling the Star Wars love haha) breve ting much coming south. Hope that goes away.
Posted by: Seina

Re: Streamflow Observations - 27/12/2015 22:18

If the Monsoon Trough activity makes it to Cairns and dumps up to the 150-200 mm it could in the next few days, it could tap more into Coral Sea moisture and winds, leading it to veer south.

Also, yes, I agree, there appear to be stronger southerly continental winds pushing against the higher 500-1000 mb thickness across the interior. The ridge to the south west really needs to weaken.
Posted by: Seina

Re: Streamflow Observations - 29/12/2015 17:39

Originally Posted By: -Cosmic- (naz)
If the Monsoon Trough activity makes it to Cairns and dumps up to the 150-200 mm it could in the next few days, it could tap more into Coral Sea moisture and winds, leading it to veer south.

Severe Thunderstorm Warning out of Cairns area for heavy rainfall (4:14 pm local time) over several hours (as well as flood warnings for some streams). Tropical low showing signs of movement smile .
Posted by: Seina

Re: Streamflow Observations - 29/12/2015 19:22

On the off chance GFS is accurate 4 days out, could see 50-100 mm rainfall in the Warrego Basin by the 2nd.
Posted by: Seina

Re: Streamflow Observations - 30/12/2015 12:47

Originally Posted By: adon
It looks like some sort of force field(feeling the Star Wars love haha) breve ting much coming south. Hope that goes away.

The front near Perth is asking a lot of questions smile .
Posted by: Seina

Re: Streamflow Observations - 30/12/2015 13:58

Originally Posted By: -Cosmic- (naz)
Originally Posted By: adon
It looks like some sort of force field(feeling the Star Wars love haha) breve ting much coming south. Hope that goes away.

The front near Perth is asking a lot of questions smile .

Regardless of the questions it raises about the trajectory of any moisture, I hope the MDB gets a drenching, and that that drenching feeds into areas which most need it. A recent report I heard about mentions the fauna and flora is not doing too well in the Basin. How accurate it is is another matter, but if it means extensive, long-lasting and moisture-sapping drought is necessarily followed by flooding rains so be it!

From fire to flood.
Posted by: Seina

Re: Streamflow Observations - 02/01/2016 17:17

Written 1st of January 3:15 pm ACDT:

The ITCZ troughing near the equator appears to be disrupted due to the tropical low moving south across the continental interior...it now looks like this low will pass by NSW and VIC, with rain affecting areas as far west as Berri and Loxton, then across towards Yarrawonga and the GDR. Chances of rain (specifically) seem to deteriorate beyond these areas, while thunderstorm probability increases near higher terrain. There is no apparent southerly track for this low in the next few days south of TAS (due to ridging in the south), so the chance of the isobaric gradients become stronger is higher along coastal fringes. Lower falls scattered 0-4 mm, higher isolated 50-100.

From the Bureau (VIC):
SEVERE THUNDERSTORM WARNING
for HEAVY RAINFALL, LARGE HAILSTONES and DAMAGING WIND
For people in the
North East and parts of the
Northern Country and
North Central Forecast Districts.
Issued at 5:02 pm Saturday, 2 January 2016.
Severe thunderstorms are likely to produce heavy rainfall that may lead to flash flooding, large hailstones and damaging winds in the warning area over the next several hours. Locations which may be affected include Wodonga, Wangaratta, Bright, Mansfield, Falls Creek and Mt Hotham.
Posted by: Seina

Re: Streamflow Observations - 02/01/2016 17:42

Again, please follow official warnings smile if you are in an area likely to be affected.
Posted by: Seina

Re: Streamflow Observations - 03/01/2016 13:41

50-150 mm falls in the upper Warrego Basin to midday today. Flows meters starting to respond. Thunderstorm activity continues in Victoria, and seems to be spreading.
Posted by: adon

Re: Streamflow Observations - 03/01/2016 22:33

Good news! Hopefully the rains continue! Everywhere needing a good drink!
Posted by: Seina

Re: Streamflow Observations - 05/01/2016 21:47

Originally Posted By: adon
Good news! Hopefully the rains continue!

Let's hope so smile .

Originally Posted By: adon
Everywhere needing a good drink!

Agreed.
Posted by: Seina

Re: Streamflow Observations - 09/01/2016 16:24

Fire and flood, from one side of the country to the other, in a week.
Posted by: Seina

Re: Streamflow Observations - 17/01/2016 12:16

16/11/2015 20:31:

Originally Posted By: -Cosmic- (naz)
There has been an increase in the local river water level in the last few days, of maybe half a metre, and the river is actually flowing. No rain has fallen that could explain this.

Spring-flow was most likely. This seems like good news smile . Plausibly meaning rain down the track.
Posted by: Seina

Re: Streamflow Observations - 21/01/2016 22:18

The remote possibility of decent rain might not be so remote after all [judging by the local radar].
Posted by: Seina

Re: Streamflow Observations - 22/01/2016 13:08

Originally Posted By: -Cosmic- (naz)
The remote possibility of decent rain might not be so remote after all [judging by the local radar].

11.6 mm early this morning grin smile . Likely more to come early afternoon with a STW issued nearby...maybe even some run-off grin .
Posted by: Seina

Re: Streamflow Observations - 22/01/2016 18:31

Minimal run-off.
Posted by: Seina

Re: Streamflow Observations - 23/01/2016 14:30

Blackwood River at Boyup Flax Mill has reached and is now falling from minor flood level in Southwest WA after significant 50-150 mm falls 18th-22nd. Some places recorded up to 75-100 mm in 24 hours [Bureau].

One station (Pemberton (DAFWA)*) recorded 174 mm in 24 hours to 9 am on the 19th, however discontinued recording after this.
Posted by: Seina

Re: Streamflow Observations - 29/01/2016 13:28

Potentially Heavy Rainfall, Run-off circa. 29th-30th of January 2016, Adelaide/Adelaide Hills, Updated Morning of 29th:
Some publicly-available modelling has been suggesting Southern Annular Mode (SAM) activity and Coral Sea moisture, may come from the south and northeast respectively during the period indicated. Empirically-modelled ranges suggest rainfall ranges (at the high end) will be 30-60 mm over 2-3 days (at this stage); at the lower end, 10-20 mm.

For this event to happen it seems a split-off upper low will come from the SAM 500-1000 thickness isotherms, with a surface low to the east of this developing feature. This surface low is partially associated with the northern 500-1000 mb thickness plume, which is now more subdued. The surface low will move north/northeast. The higher-pressure ridges to the southwest and southeast prevent it moving in those directions.

However, 850 mb winds and humidity are from near Cairns, 700 hPa from near Broome, and surface from the south. As the 850 hPa winds reach the south-eastern higher-pressure ridge, they veer west, across the Tasman Sea. Therefore, the upper/surface low combination must move more north, towards Adelaide, with one low feeding the other. Both draw in moisture, mainly from southern and polar maritime directions, which adds to convection.

Falls of 20-40 mm have already been widespread through the Central and Northern Hills to 9 am this morning. A Severe Weather Warning has also been issued [10:11 am ACDT].
Posted by: Seina

Re: Streamflow Observations - 29/01/2016 17:50

Streamflow run-off risk potentially increased. Significant rain rates.
Posted by: Seina

Re: Streamflow Observations - 30/01/2016 19:23

This low-pressure system is having some effects: a staggering 416 mm at Gray AL* since 9 am on the 26th, with 221 to 9 am on the 29th, in the South Esk River Catchment on Eastern Tasmanian Slopes, with moderate flood levels reached (still current) at South Esk River at Fingal. St Pauls River at Lewis Hill also hit moderate flood class.
Source: Bureau.
Posted by: Seina

Re: Streamflow Observations - 31/01/2016 12:00

Renewed flood warning for South Esk River, Tasmania [9:56 am EDT].
Posted by: Dipole

Re: Streamflow Observations - 01/02/2016 13:25

BOM said (just now) that all states and NT, are on flood watch or warning. 4th time in 14 years.

https://pbs.twimg.com/media/CaGDZ9PUcAEpJfy.png:large
Posted by: Seina

Re: Streamflow Observations - 01/02/2016 19:23

Re: all states/territories on flood watch/warning. They may have been smile (although perhaps I wasn't checking it at that time),...it looks to have been temporary if so.
Posted by: Seina

Re: Streamflow Observations - 21/02/2016 21:04

Opening Post:
Originally Posted By: -Cosmic- (naz)
Streamflow Lowest in Memory…More than 20 years.

Dwarfed.
Posted by: Seina

Re: Streamflow Observations - 05/03/2016 12:17

Well, just for the benefit, this is what I wrote (and saved) earlier in the week:
GFS +168/ACCESS-G +192 HR Charts, 1100/2300 EDT, Monday 7th of March
(Currently 1st of March; updated with rain, 3rd-5th) [Ceduna-Streaky Bay SA, possibly Adelaide Hills]


Rain, Thunderstorms Ceduna-Streaky Bay SA, possibly Adelaide Hills

Principles:
  • Temperatures of upper-level air masses can determine instability.
  • Hot land surface => cooler upper levels (convection).
  • Change [increase] in thickness [isopleths] facilitates increase in movement of moisture from NW-NE (amount of water vapour an air-mass can hold gradually increases with temperature, and winds are from inland tropics, and Broome area).
  • Increased in moisture in the lower atmosphere forced to converge and convect [near Adelaide] (increased isobaric gradient).
  • Upper milder low forces upper-air temperature down, increasing instability and potential for rain [from thundery showers/thunderstorms].
Ceduna-Streaky Bay Area: 20-40 mm over 3-4 days. [now maybe 2-3].
Adelaide area: possible 5-10 mm over same period slightly shifted by hours, maybe a little more at this stage (few mm).
According to one forecast: Streaky Bay: 82% chance of 28.5 mm Sunday, 76% chance of 13.5 Monday. 54% chance of 2.6 mm, Adelaide Hills tomorrow; 77% chance of ~ 15 mm Monday.
Posted by: Seina

Re: Streamflow Observations - 08/03/2016 21:26

Technical Details: Circa 6th to 10th of March 2016, Updated 8th
[*] Indicates sustained by the 5th of March.

Upper low aligned NE-SW of 500-1000 mb thickness isopleths/500 hPa isoheights – surface troughing the same. Significant [higher] 500-1000 mb thickness plume from north, down between SA and VIC/NSW/QLD, directing [surface] warm, dry northerlies off the Great Dividing Ranges towards western VIC [eastern flank of plume].

Off western flank of same plume, higher dew-point temperatures down [the] continental interior, directing moisture south towards upper low/surface troughing.

Upper 500 hPa isoheights and winds show direction of moisture is from far west [from near troughing activity in mid-Indian Ocean/Broome, with significant troughing near Geraldton due to temperature gradient of 10+ degrees C up the coast], with isoheights very similar west [troughing activity]-to-east [upper low] [*].

Surface winds from the NNE (down the centre), with much higher temperatures and grading dew-points [*].

Significant wind gradient at 850 hPa, with convergence near Adelaide (NW-SE) [*].

850hPa to [the] northeast +22-24 degrees C [*], southwest (near upper low/surface troughing combination) 6-8 degrees C [*]; gives significant 850 hPa temperature gradient.

Significant relative humidity across Adelaide area at 700 hPa (70-90%) [*].

500 hPa temperatures much higher (-6 to -8 degrees C) [*] as [shallow] upper low pushes milder, humid westerlies [at 500 hPa] towards hot, dry northerlies at surface.

Potentially major instability in region of thickness/isoheights/moisture convergence [in NW-SE direction].

[The difference in the position of the upper level disturbance [low] – 2 of them [6th-7th] – from GFS +168 hours to +48 hours is about 5 degrees latitude (now further north). This could make a major difference to potential thunderstorm activity with CAPE “leaking” from near Broome of magnitude ~ 800-1000+ J/Kg, by Tuesday morning, for SA.]

As of the 7th [1-2 days out from major instability]:
CAPE: 750-900 J/Kg; LFTX: -2 to -4, RH: 70-90%; Temp: Max: 28 degrees C; Cloud-cover 100%.

Recorded so far: 9.8 mm [6th]; potential 20-40 mm, 40-80 isolated. Bureau forecast (5:09 pm CDT, 7th): ~ 5 to 25 mm by the 10th.
Posted by: Seina

Re: Streamflow Observations - 13/03/2016 11:37

Areas of falls 50-100 mm in the week ending 12th of March across SA. Areas of falls exceeding 200 mm in the same time east of Mt. Isa, QLD.
Posted by: Seina

Re: Streamflow Observations - 19/03/2016 22:02

Possibility of rain or shower activity of some description nearer the end of the month smile .
Posted by: Seina

Re: Streamflow Observations - 25/03/2016 22:03

1.7 mm yesterday -- not much.
Posted by: Seina

Re: Streamflow Observations - 11/04/2016 20:27

May be potential for flooding Albany Region (WA) next 1-2 days.
Posted by: snowbaby

Re: Streamflow Observations - 13/04/2016 16:43

Yes naz minor flooding in Albany hinterland
Posted by: DaveM

Re: Streamflow Observations - 13/04/2016 16:46

Hope those rains get into the wheat belt!!
Posted by: Seina

Re: Streamflow Observations - 13/04/2016 16:58

Thanks for info snowbaby smile . Rain/thunderstorms in forecast still look ok for today till afternoon for Katanning area.
Posted by: Seina

Re: Streamflow Observations - 13/04/2016 22:40

GFS's WA wheatbelt forecast from earlier in the day would be a blessing for here atm.
Posted by: Seina

Re: Streamflow Observations - 19/04/2016 19:50

Recent rains that impacted Perth, WA (25 to 49 mm of them), affected river flows.
Posted by: Seina

Re: Streamflow Observations - 24/04/2016 11:47

Winter is coming grin smile !!
Posted by: Seina

Re: Streamflow Observations - 24/04/2016 14:37

Originally Posted By: -Cosmic- (naz)
Winter is coming grin smile !!

Statement with more meaning smile :

Proposed Dynamics, April-May 2016:

The SAM may have a strong influence on Southern Australian wind patterns heading into May [2016], with surface ridging to the north and east expanding over the continental interior, directing wind from east to west [the near-opposite required for a -IOD [1] or North-West Cloud-Band formation, surface-based]. This ridging may actually provide part of the mechanism for SAM rossby-wave [upper trough] development.

With winds losing moisture across the continental interior in a [generally] ESE wind stream, this can both reduce cloud-cover over South-eastern Coasts (generating clearer-sky nights and potential for frosts), and across Eastern parts of the interior, increasing moisture and latent heat gradients SW-to-NE. These ESE winds can also have the effect of evaporative cooling at the surface, leading to inversions and more stable vertical profiles in inland NT/WA (hence more storm activity east of inland troughing in eastern areas).

On the other hand, for the last 2-5 weeks the SIOD has been presenting with blocking troughing from approximately Broome to Albany, allowing the ESE winds over interior WA to veer south along the WA coast. In addition, an IO ridge west of Perth [WA] allows moisture from further away from the Central and Eastern IO to interact with the upper edge of the SAM at 500 hPa, providing more stimulus for WA coastal troughing. This SIOD troughing seems to be broken down with surface ridging moving east.

The outcomes of this are that once the WA troughing [influenced by the SIOD and ESE sub-tropical and tropical winds] breaks down, it allows stronger SAM activity to reach southern coasts and a contraction of the Hadley Cell further north.

Another moderate upper trough with a drier, preceding cooler air mass is due for SW WA in the next couple of days, with the WA-SIOD troughing pushed inland. Dewpoints in the higher 14-18 C range at the moment [to the east of the trough axis].

The more northerly higher dewpoints and cloud-cover may actually make it to Geraldton with the IO influence. The WA trough moving inland also means the ESE wind component veers towards SA [E-ENE], bringing increasingly milder temperatures. However, at 500 hPa the air is still relatively warm, which brings stability [to 27th-28th April or thereabouts].

There seems to be a rather strong moisture in-feed at about 700 hPa from the deep tropical IO about this time [27th-28th, ACCESS; GFS]. Whether this will be sustained remains to be seen.

Signs of significant (20-40 mm) rain by early May.

[1]: Nature 510, 254–258 (12 June 2014) doi:10.1038/nature13327.
Posted by: Seina

Re: Streamflow Observations - 08/05/2016 16:01

28.7 mm since the 27th of April has eased drought conditions [followed by about a day break around the 5th], and reduced the risk of soil erosion smile in the event of severe weather.
Posted by: Seina

Re: Streamflow Observations - 09/05/2016 16:36

Originally Posted By: -Cosmic- (naz)
28.7 mm since the 27th of April has eased drought conditions [followed by about a day break around the 5th], and reduced the risk of soil erosion smile in the event of severe weather.

Flooding issues, trees down, debris everywhere... grin smile shocked !!

50+ mm (less than 24 hours).
Posted by: Seina

Re: Streamflow Observations - 10/05/2016 18:54

Infrastructure damage, fallen branches, road debris, flash-flood upper catchment frown (in approximately 3 hours). A total of 106.9 mm to start May 2016 smile [1st 12 am to 10th, 9am].

...and soil erosion!
Posted by: Seina

Re: Streamflow Observations - 11/05/2016 18:04

Originally Posted By: -Cosmic- (naz)
flash-flood upper catchment frown (in approximately 3 hours).

In other words, in the space of 2-3 hours, more than half the rain that had fallen to 5 pm filled a river basin [from scratch] to maybe half full and flowing vigorous downstream. What a sight to behold!
Posted by: Seina

Re: Streamflow Observations - 23/05/2016 22:24

The event of the 9th was clearly a flash-flood. Flows have not been sustained.
Posted by: Seina

Re: Streamflow Observations - 24/05/2016 16:56

Written 22nd of May 2016 [Updated 23rd]:
The southern rossby-wave is now more established with the 500-1000 mb thickness much further north than in previous months (March-April) [576 line]. The northerly influence of tropical in-feeds seems to have been tempered in the south by near-constant ridging across the interior (albeit with occasional gaps allowing residual IO moisture to anchor on WNW-ESE 500 hPa wind gradients, hence more cloud-cover). The N-S ridging along the East Coast seems to be allowing the southern rossby-wave to build more momentum in the deep SW (hence recent heavy 1-day 50+ mm falls in SW WA), however it is also directing higher-dewpoint winds and moisture onto northern QLD coasts and inland over the GDR, bringing areas of rain (exceeding 100 mm in 1-2 days). As these winds head south, they lose moisture over interior QLD, NSW and VIC, before increasing upon approaching south-eastern coasts.

As the southern rossby-wave moves W-WSW over the next 4-5 days (i.e. 20th-25th), the winds that brought a significant change in upper trough (500 hPa) activity to SW WA (and near-surface temperatures down) will spread across coastal SA, and inland southern VIC, bringing cooler conditions. A secondary upper (and surface) trough plume seems likely to develop near south-central coastal SA on Wednesday, bringing a 700 hPa and 850 hPa IO moisture plume to a broader south-easterly region (SA, VIC). This may bring a much higher chance of 20-40 mm falls to A. coastal, central SA, and B. the SA Mallee, with a surface low forming as it approaching this area. Both ACCESS and GFS more-or-less concur on this situation (at present, and since the 20th). It will be interesting to see what observations actual show (i.e. whether run-off responds more noticeably in the 4-5 days). If rainfall to Saturday exceeds 100 mm, potential for moderate or significant run-off seems likely to increase dramatically.
Posted by: Seina

Re: Streamflow Observations - 25/05/2016 23:05

Originally Posted By: -Cosmic- (naz)
A secondary upper (and surface) trough plume seems likely to develop near south-central coastal SA on Wednesday, bringing a 700 hPa and 850 hPa IO moisture plume to a broader south-easterly region (SA, VIC). This may bring a much higher chance of 20-40 mm falls to A. coastal, central SA, and B. the SA Mallee, with a surface low forming as it approaching this area. Both ACCESS and GFS more-or-less concur on this situation (at present, and since the 20th).

Extended to North-central VIC (near Mt. Buller).
Posted by: Seina

Re: Streamflow Observations - 29/05/2016 14:55

Originally Posted By: -Cosmic- (naz)
If rainfall to Saturday exceeds 100 mm, potential for moderate or significant run-off seems likely to increase dramatically.

No falls [that I could tell from Bureau data] exceeded 100 mm between 9 am the 23rd and 28th.
Posted by: Seina

Re: Streamflow Observations - 04/06/2016 10:27

Serious weather expected to develop near Sydney, NSW next 24-48 hours. Much higher risk of flooding suspected.
Posted by: Seina

Re: Streamflow Observations - 04/06/2016 21:46

Originally Posted By: -Cosmic- (naz)
Serious weather expected to develop near Sydney, NSW next 24-48 hours. Much higher risk of flooding suspected.

Additional potential focal points [over the next week] are Wollongong NSW, Strahan TAS, Mt. Gambier SA, Alice Springs NT, and Perth WA...
Posted by: Seina

Re: Streamflow Observations - 05/06/2016 18:59

Georges River at Liverpool Br (gauge 566054) near Sydney is approaching major flood level (6 pm local time). The nearest rainfall gauge to this site has recorded 225 mm in 2-3 days. A site possibly further upstream (Ingleburn, gauge 566057) has recorded 350 mm in the same period.
Posted by: Seina

Re: Streamflow Observations - 05/06/2016 19:15

Also, as the low-pressure trough (Bankstown Airport AWS area) approaches, there is a chance rainfall may pick up intensity if it hasn't already done so.

...Mersey River at Kimberley (Northern-Central TAS) has hit major flood level (site 091266, 4.00) and rising. [I'm assuming that's not an error smile ].
Posted by: Seina

Re: Streamflow Observations - 09/06/2016 23:02

Major Flood Warnings were issued for Nepean (NSW) and Mersey (TAS) catchments at 10:04 and 9:44 pm EST respectively, 5th of June.

An error at Mersey River at Kimberley!? on the 6th frown , bad timing… Despite this, as at 6:22 pm EST, 6th of June 2016, several Tasmanian rivers had major flood warnings. Of those warnings Meander River at Strathbridge and Macquarie River at Cressy Pumps were still rising, at 6:30 pm EST.

Some Context for Observations, to the 10th of June
Written earlier 4th of June 2016, updated same day, 5.50 pm CST and 9.50 pm CST, 5th:
Additions [], 5.50 pm CST, 7th, excluding east-coast moderate flooding note.

A tropical thickness moisture plume is expected to interact with a 500-hPa cut-off low, forming near the East Coast (approximately west of Sydney). 700-hPa relatively humidity is forecast (by ACCESS and GFS, 4th and 5th) to be significantly above the 90% threshold, with lower-levels (850-hPa) saturated. The thickness plume extends (ACCESS-R +24 hours, 2200 EST, 4th) to the near-tropics (northern Coral Sea), with higher wind speeds. A higher-pressure system at 700 hPa (near Broome) seems to be facilitating westerlies being drawn into the upper-low (near Sydney), which appears to be forced to intensify as the difference between 850 and 500 temperatures and dewpoints increases. Of concern is the convergence of upper and surface winds from 500 hPa around the Greater Sydney Area. This could induce a forced equilibrium between westerly and easterly airstreams, forcing the warmer moisture from the north to accelerate over its colder counterpart, producing a significant moderation of near-surface air temperatures and increase in dewpoints to around 16-18 degrees C. This forcing is made “worse” by the fact of the lower 500-1000 mb thickness approaching from the west, which means as the moisture plume accelerates into the lower thickness, it will have to rain out as temperatures fall, hence higher possible precipitation rates (i.e. greater than 10 mm/hr, sustained).

The upper 500-hPa low seems likely to retrograde slightly west as it comes under the influence of an approaching long-wave cold-front from the deep southwest, and a ridge north of NZ. It (the upper low) may split. [Cold-front has passed through south-western WA, bringing falls 50+ mm locally near Perth, 9 am 7th of June.]

The winds from the east (south Coral Sea) appear stronger than in the west, implying a surface high near Broome is doing the forcing. Also of note is the winds in [Central] QLD are from the west, not east [4th-5th], implying the surface high has been displaced (which looks clear enough). If rain streams become strong enough, moderate flooding and the quantity of rain required to reach moderate flood level look possible. The north-eastern flank of the 500-hPa cut-off low has been under the influence of orographic effects near the Great Dividing Range [6th of June], coupled with the southern edge/flank nudging northern TAS with possibly similar effects.

------------------------

There has been infrastructure and property damage during this East-Coast and Tasmanian flood-period, as well as a loss of life frown [ABC news]. Suffice to say the rain may not be over yet, with an additional rain/shower-period to follow to the 10th. [Areas around Strahan TAS and North-Central TAS may be at serious risk of additional flood-inducing rains within the next 2-3 days, that is 8th-10th. A third cold-front approaches Tasmania’s west coast (9th), following the cut-off low affecting Central SA and parts of Gippsland, VIC (7th-9th).]

The south-western flank of the Broome [700-hPa] high seems to have been directing 700-hPa Indian-Ocean moisture towards Central Inland SA/Border-region NT [7th-8th].

[In the week ending 8th of June 2016, falls of 400+ mm have been recorded along the NSW coastline, and Central-western TAS – Source Bureau.]
Posted by: Seina

Re: Streamflow Observations - 18/06/2016 22:27

Period to the 21st of June may be serious for eastern states rainfall-wise.
Posted by: Seina

Re: Streamflow Observations - 22/06/2016 20:27

Originally Posted By: -Cosmic- (naz)
Period to the 21st of June may be serious for eastern states rainfall-wise.

Warner Alert slightly west of Brisbane recorded 199 mm in the 24 hours to 9 am, 20th (local time). Cabbage Tree Creek at Old N'n Rd (near Brisbane) peaked above major flood level (44.44 m, ~ 17:20 pm local time, obs). Nearest gauges have both had more than 110 mm in 8.5 hours.
Source: Bureau.

5:25 pm CST, 19th of June: convergence seemed apparent slightly west or near Brisbane QLD, as the barometric pressure fell (radar).


For anyone interested:
Written 18th of June 2016:
It seems fairly clear a lagging 700 hPa humidity plume [moving from west-to-east across continental interior] has or is picking up on a much higher dewpoint thickness plume running diagonally north-south through the interior. The latter [higher dewpoint thickness plume] has partially facilitated [helped] a near-stationary upper 500-hPa plume aligned northwest to Adelaide SA to re-generate and clip the upper north-eastern quadrant of an elongated surface higher-pressure ridge aligned at roughly the same angle. This surface ridge undercuts the 500-hPa developing [re-generating] low in such a way to force intensification, and it is very clear on the ACCESS-R +24 Hours run for 1000 EST Sunday 19th of June. This is a cut-off 500-hPa low with vigour – the southern long-wave trough has essentially been cut off by the ridge. A high off-shore near Sydney is also pushing winds towards the coast, so convergence may be an issue. This interpretation doesn’t factor in the Great Dividing Range].
Posted by: Seina

Re: Streamflow Observations - 10/07/2016 22:15

9.45 pm CST: After checking ground conditions and rainfall observations, it seems apparent the local catchment is saturated – a lot of surface water is still soaking in after 8-10 mm overnight. The local weir [Bureau] also started responding after this rain which suggests the threshold for increasing streamflow is maybe 10-15 mm more, depending on how much time is left between the next rain/showers at what has fallen in the last 24 hours. Not necessarily expecting a great deal of rain from the next system, though things (such as snow) seems a greater chance. I think we might see 35-40 mm by Wednesday. If we get more, great. For snow, a 532 long-wave thickness plume is pushing up from the deep south towards/behind the spiral low currently in the Bight (ACCESS-R).
Posted by: Seina

Re: Streamflow Observations - 15/07/2016 20:15

Originally Posted By: -Cosmic- (naz)
9.45 pm CST: After checking ground conditions and rainfall observations, it seems apparent the local catchment is saturated – a lot of surface water is still soaking in after 8-10 mm overnight. The local weir [Bureau] also started responding after this rain which suggests the threshold for increasing streamflow is maybe 10-15 mm more, depending on how much time is left between the next rain/showers at what has fallen in the last 24 hours. Not necessarily expecting a great deal of rain from the next system, though things (such as snow) seems a greater chance. I think we might see 35-40 mm by Wednesday. If we get more, great. For snow, a 532 long-wave thickness plume is pushing up from the deep south towards/behind the spiral low currently in the Bight (ACCESS-R).

49.5 mm recorded for the period from 9 am 11th of July to 12 midnight the following day (39 hours). The local river level rose and fell in that time to almost a metre above the datum (no flooding), with the river becoming impassable. Moisture seemed plentiful, however temperature changes appeared too stable for corresponding changes in wind-direction to have much impact on rainfall rates, which were not sustained and quite sporadic. Winds were inevitably an issue for many in the region with sustained winds and gusts of at least gale-force magnitude (enough to launch 10-20 kg chairs and tables and snap/break medium-sized tree branches). For this reason in particular it was not pleasant on the night of 11th-12th, nor for power-losses, which were extensive (power lines hanging on the ground). From what I’ve heard, much of the Adelaide city area did have winds, however changes in the land elevation (into the Adelaide Hills) probably assisted the winds to be more damaging. In summary, the wind ferocity dwarfed and even quelled the rain rate ferocity. In a sense this could be seen coming from the shear closeness of isobaric contours as the system approached from the deep south, to north – the air simply did not have time to warm-up as it headed north (hence the wind issue).
Posted by: adon

Re: Streamflow Observations - 16/07/2016 00:08

I'm not sure if this is the right place to post this but we could be looking at a pretty large flow coming down the Darling river to continue the excellent flows coming down from the rains in NSW. Good to see the whole catchment getting some action.
Posted by: Seina

Re: Streamflow Observations - 16/07/2016 00:51

Originally Posted By: adon
I'm not sure if this is the right place to post this but we could be looking at a pretty large flow coming down the Darling river to continue the excellent flows coming down from the rains in NSW. Good to see the whole catchment getting some action.

You're welcome to smile .
Posted by: Seina

Re: Streamflow Observations - 17/07/2016 23:00

Originally Posted By: -Cosmic- (naz)
Originally Posted By: adon
I'm not sure if this is the right place to post this but we could be looking at a pretty large flow coming down the Darling river to continue the excellent flows coming down from the rains in NSW. Good to see the whole catchment getting some action.

You're welcome to smile .

Just out of curiosity, why do/did you think that smile ?

[Also for information, I will be discontinuing regular/frequent posts in this thread if contributors are not serious (committed) about getting their queries/questions addressed/discussed.]
Posted by: adon

Re: Streamflow Observations - 22/07/2016 00:22

Hahah I read a few of the posts and assumed it could have been one for your particular area. That's all.

On the Darling river front, around 5000 megs a day are going into the Menindee lake ATM. I have been told by a person with local connections that they will be letting the flow through to the lower reaches of the river soon. Great news! Looking like some more very substantial flows are heading for the Darling with the Bogan and Macquarie rivers in flood again. Some impressive figures too on the flow rates with 51000meg flow rate in parts of the Macquarie.
Posted by: Seina

Re: Streamflow Observations - 22/07/2016 12:22

Originally Posted By: adon
On the Darling river front, around 5000 megs a day are going into the Menindee lake ATM. I have been told by a person with local connections that they will be letting the flow through to the lower reaches of the river soon. Great news! Looking like some more very substantial flows are heading for the Darling with the Bogan and Macquarie rivers in flood again. Some impressive figures too on the flow rates with 51000meg flow rate in parts of the Macquarie.

I had a look at the river data for Dandaloo and Narromine in the Bogan catchment (on the Bureau’s website). While Dandaloo has a full history on the graph, it is very hard to tell (at Narromine) how reliable it is – with only a few data points. If you think the correspondence you have had are reliable, then great smile . Let’s see if it translates further downstream.
Posted by: Seina

Re: Streamflow Observations - 22/07/2016 15:53

Originally Posted By: adon
Hahah I read a few of the posts and assumed it could have been one for your particular area. That's all.

It is one for wherever people wish to post their observations from smile .
Posted by: Thunderstruck

Re: Streamflow Observations - 26/07/2016 23:28

Thought this thread would be overflowing over the last 72hrs...pun intended!

TS cool
Posted by: Seina

Re: Streamflow Observations - 27/07/2016 20:42

Originally Posted By: Thunderstruck
Thought this thread would be overflowing over the last 72hrs...pun intended!

TS cool

Flooding issues required more attention (e.g. fishing infrastructure out of water and relocating it).

This is it in a nutshell:

Written 22nd of July 2016:
Hypothesis:
The local river responded (rose) after 19.2 mm of rain in the 24 hours to 9 am, 20th of July. Observations suggest most of the rise occurred after midnight [Bureau], meaning it took 3.5 mm of moderate-to-heavy rain to reach the response threshold. The maximum observation based soil moisture that can be replenished by water soaking in is about 34.2% [own estimate] - the rest is soil grains and aquifers. The estimated change in water level was 0.198 metres [own estimate], with soil moisture up ~1.047% from the previous day. Assuming a bell-shaped of about 60 mm distributed over a 5-day period, the maximum stream level height is approximately ~1.8 metres, with soil moisture increasing by another ~1.019%. This is enough for some flooding; the current estimated stream level is 0.775 metres.
The difference between the observed (estimated) soil moisture and extrapolated 5-day soil moisture may be due to the fact surface-water is still soaking into the ground across areas most affected, which has been observed. The fact it was/is still soaking in after another 19 mm suggest there less capacity in underground systems, hence more surface-water runoff potential. Water is not a very compressible fluid [1].

Documented (from 12 am, 24th).
60 mm in ~63.3 hours.
70 mm in ~65.25 hours.
87.5 mm in 68.3 hours.

Minor low-land flooding observed north of Tiers Road. Large debris caught under the ford near Oakbank Racecourse Main Entrance.

The line of debris in paddocks [next morning] indicates the banks were breached by anything up to 5-10 metres.

[1]: http://water.usgs.gov/edu/compressibility.html
Posted by: adon

Re: Streamflow Observations - 27/07/2016 20:49

My contacts are the website for the Bogan/Mac rivers! But I used to work with a bloke from Pooncarie and he was told that flows will be coming down soon. Great to see decent flows coming into the Menindee lakes. Not massive by any means but at least levels are going up. Of course the way floods tend to go is that they tend to spread the flow out as they go downstream but this should mean that a good solid flow will be coming into the darling above Bourke to add to the flows coming down from the border rivers. And from accounts I have bread from up there. The ground is so wet that much of this will be flowing and not soaking.
Posted by: Seina

Re: Streamflow Observations - 27/07/2016 20:55

Originally Posted By: adon
My contacts are the website for the Bogan/Mac rivers! But I used to work with a bloke from Pooncarie and he was told that flows will be coming down soon. Great to see decent flows coming into the Menindee lakes. Not massive by any means but at least levels are going up.

I can't recall exactly,, but were they [the lakes] recently empty?
Posted by: Seina

Re: Streamflow Observations - 27/07/2016 21:03

Last night's flooding eclipsed that of 3rd of September 2010. We have to go back before then to find similar conditions.
Posted by: Seina

Re: Streamflow Observations - 28/07/2016 20:45

Originally Posted By: -Cosmic- (naz)
Originally Posted By: adon
My contacts are the website for the Bogan/Mac rivers! But I used to work with a bloke from Pooncarie and he was told that flows will be coming down soon. Great to see decent flows coming into the Menindee lakes. Not massive by any means but at least levels are going up.

I can't recall exactly,, but were they [the lakes] recently empty?

After watching the part of the news on Menindee Lakes, it seems it's not a matter of whether flows make it down there...but rather a human decision about whether to release flows from QLD into Western NSW.
Posted by: adon

Re: Streamflow Observations - 28/07/2016 22:27

That's a load of bollocks I'm afraid. Most of the flows coming ATM are coming from flows in NSW anyway.

For some reason everybody seems to assume that there is a great bloody dam somewhere in Qld that is hogging all the water from the Darling. There is no such massive dam!

Cubby seems to cop the most of the blame too but they are NOT ALLOWED to divert water unless the Culgoa river is at a certain level of FLOOD. Very small amounts are allowed to be pumped but I notice that nobody is doing recent aerial shots of brimming full water storages there. That's because they are not full! It ruins a good story.
Posted by: adon

Re: Streamflow Observations - 28/07/2016 22:31

I went for a drive down near Bendigo today and noticed that mat of the streams from wedderbrun to Bendigo either has trickles in them or had a recent flow, considering not much rain has fallen this week, I can only assume that not the ground is wet enough to be creating runoff from most rainfall events now. Good sign but also probably a caution of flooding if a big rain does come soon.
Posted by: samboz

Re: Streamflow Observations - 29/07/2016 08:48

Anyone know the situation with the "35km long dam wall" locals at Dirranbandi spoke of 15yrs ago when we stopped there overnight. Is that on Cubby Stn or is it all bs.

Supposed, according to anecdotal things I have heard/read to be having some impact on Darling catchment.
Posted by: adon

Re: Streamflow Observations - 30/07/2016 02:22

In order for there to be this "theft" of water for "greedy cotton farmers". There has to be water in the rivers to steal. It seems to slip the mind of the bleeding hearts that there has been a rather nasty drought up there for quite a while. Rivers need rain to creat runoff and groundwater seepage to let rivers flow. No dam wall can steal what is not there.......
Posted by: Seina

Re: Streamflow Observations - 30/07/2016 13:16

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Originally Posted By: adon
My contacts are the website for the Bogan/Mac rivers! But I used to work with a bloke from Pooncarie and he was told that flows will be coming down soon. Great to see decent flows coming into the Menindee lakes. Not massive by any means but at least levels are going up.

I can't recall exactly,, but were they [the lakes] recently empty?

After watching the part of the news on Menindee Lakes, it seems it's not a matter of whether flows make it down there...but rather a human decision about whether to release flows from QLD into Western NSW.


Originally Posted By: adon
That's a load of bollocks I'm afraid. Most of the flows coming ATM are coming from flows in NSW anyway.

For some reason everybody seems to assume that there is a great bloody dam somewhere in Qld that is hogging all the water from the Darling. There is no such massive dam!

Cubby seems to cop the most of the blame too but they are NOT ALLOWED to divert water unless the Culgoa river is at a certain level of FLOOD. Very small amounts are allowed to be pumped but I notice that nobody is doing recent aerial shots of brimming full water storages there. That's because they are not full! It ruins a good story.

The report I watched didn’t say anything about QLD hogging any water, or big dams, but it did highlight the plights (desperation for more business) of the local populations, and the poor state of the riparian environment (i.e. a lack of wildlife). It was about the Menindee Lakes from their perspective (although other regions could have different perspectives again, granted).

I assumed the report was up-to-date and valid because I had no reason to assume otherwise. I’m not saying your account is wrong, but then I’m not discounting the report I saw.

There might well be some flows coming down towards that area, and I’m sure, with robust evidence of it, that would be a good thing. However, with any flows in such a vast inland environment, things can take time – a lot of time.

I would like to see greater flows (and relief) regardless smile .
Posted by: adon

Re: Streamflow Observation - 30/07/2016 20:55

The thing that a lot of people don't seem to realise is that while there may be the odd "rogue pumper" along the river, most have not been allowed to pump if indeed there was a flow coming down the river anyway. There was an embargo placed on pumping a few years ago when flows stopped. Apart from some dams in a couple of the feeder tributaries of the Darling, it is a lot more unregulated than the Murray/bidgee. The notion that the low flows were caused by human intervention is wrong as there was no flows for a long time to hold back. The Murray would have also run dry if it was not for the massive dams and regulated flows. The Menindee lakes were in their natural state a system that filled only with floods. The river is diverted into them in order to fill them. The only stupid decision in regards to them was this monumentally dumb idea of keeping the lower lakes (previously an estuary) fresh. Also flushing out the Murray mouth. It takes a massive amount of water to keep them fresh because of the huge amount of evaporation coming from them. This used us huge amounts of stored water to flush the mouth in dry times when the mouth would have naturally closed is stupidity at its worst. Everybody keeps attacking cotton growers for wasting water when one of the biggest wastes is the lower lakes/Murray mouth. Over 1000GL are evaporated (wasted)just to keep it fresh. Double Sydney harbour!
More to flush the mouth.

Posted by: adon

Re: Streamflow Observation - 30/07/2016 21:07

Just did some checking and the evaporation consumption of the lakes would use over half of the Menindee lakes at full capacity (1731GL). Of course this doesn't include the losses getting the water there to evaporate which in itself would be substantial.
Posted by: Seina

Re: Streamflow Observation - 30/07/2016 21:56

Originally Posted By: adon
The notion that the low flows were caused by human intervention is wrong as there was no flows for a long time to hold back. The Murray would have also run dry if it was not for the massive dams and regulated flows. The Menindee lakes were in their natural state a system that filled only with floods. The river is diverted into them in order to fill them. The only stupid decision in regards to them was this monumentally dumb idea of keeping the lower lakes (previously an estuary) fresh. Also flushing out the Murray mouth. It takes a massive amount of water to keep them fresh because of the huge amount of evaporation coming from them. This used us huge amounts of stored water to flush the mouth in dry times when the mouth would have naturally closed is stupidity at its worst. Everybody keeps attacking cotton growers for wasting water when one of the biggest wastes is the lower lakes/Murray mouth. Over 1000GL are evaporated (wasted)just to keep it fresh. Double Sydney harbour!
More to flush the mouth.

I think given the sparseness of population centres further inland, the impact of withdrawals from the basin for irrigation, agricultural/horticultural or domestic purpose might be lesser than if populations had increased more in-line with centres on the coasts. A lot could also be said of the types of regional underground aquifers and soil-types in given areas, as these would inevitably contribute to the longevity (or lack of) for respective farming communities’ (i.e. farming practices remaining sustainable). It seems fairly clear inland areas of the Murray-Darling [riparian environments] are unlikely to remain “green” all-year round, and indeed that is most definitely an unrealistic notion.

To be honest though, all this talk about who’s at fault or to blame for whatever I would think is not helping the situation. I don’t take sides – I look at the science. Such science suggests we’re having the wettest “usual” start to the southern agricultural farming season in maybe 20 years (give or take), that’s welcome in any language, because water is flowing like it hasn’t been for years! It would be a welcome note to hear about artesian upwelling regionally smile .
Posted by: adon

Re: Streamflow Observation - 30/07/2016 23:07

Originally Posted By: -Cosmic- (naz)
[quote=adon]The notion that the low flows were caused by human intervention is wrong as there was no flows for a long time to hold back. The Murray would have also run dry if it was not for the massive dams and regulated flows. The Menindee lakes were in their natural state a system that filled only with floods. The river is diverted into them in order to fill them. The only stupid decision in regards to them was this monumentally dumb idea of keeping the lower lakes (previously an estuary) fresh. Also flushing out the Murray mouth. It takes a massive amount of water to keep them fresh because of the huge amount of evaporation coming from them. This used us huge amounts of stored water to flush the mouth in dry times when the mouth would have naturally closed is stupidity at its worst. Everybody keeps attacking cotton growers for wasting water when one of the biggest wastes is the lower lakes/Murray mouth. Over 1000GL are evaporated (wasted)just to keep it fresh. Double Sydney harbour!
More to flush the mouth.


Originally Posted By: -Cosmic- (naz)
I think given the sparseness of population centres further inland, the impact of withdrawals from the basin for irrigation, agricultural/horticultural or domestic purpose might be lesser than if populations had increased more in-line with centres on the coasts.
Yes this is correct. It would be nice to have a few more out here but a country with millions more would be a very heavy load for the already erratic water resources we have.

Originally Posted By: -Cosmic- (naz)
A lot could also be said of the types of regional underground aquifers and soil-types in given areas, as these would inevitably contribute to the longevity (or lack of) for respective farming communities’ (i.e. farming practices remaining sustainable). It seems fairly clear inland areas of the Murray-Darling [riparian environments] are unlikely to remain “green” all-year round, and indeed that is most definitely an unrealistic notion.
Absolutely the permanent green, flowing rivers idea is one born out of Europe and nurtured east coast. Inland is a much different story.

Originally Posted By: -Cosmic- (naz)
To be honest though, all this talk about who’s at fault or to blame for whatever I would think is not helping the situation. I don’t take sides – I look at the science. Such science suggests we’re having the wettest “usual” start to the southern agricultural farming season in maybe 20 years (give or take), that’s welcome in any language, because wauter is flowing like it hasn’t been for years! It would be a welcome note to hear about artesian upwelling regionally smile .

Once again I agree. This all gets bogged down in politics and idealism. I generally try to distance myself from the issue I am looking at in order to try to see things from a different and non biased point of view.

I am a believer in a system of regenerative agriculture that substantially lessens if not ends the need to irrigate. It means not growing certain crops for sure and that is something we need to investigate more. It would be a massive change to our farming practices and one I do not see happening for a very long time if ever. But that is another story.

The idea of only growing high value crops with the irrigation water is also flawed. Why? Because for a start most of those high value crops tend to bepermanant crops like tree crops. These have to be watered to stay alive where as annual crops simply do not get grown if water is not available.

On the other hand, we seem to hear an awful lot about environmental flows in rivers but we never hear of environmental drying of them. Inland rivers were always highly erratic in flows and rivers running dry before the dams and weirs was common. Now they are expected to be running bankers all year. You can't have it both ways. Flows and dry rivers was the norm.

It just makes me angry when the usual suspects are rolled out to blame for a river running dry. Hardly any mention of lack of inflows ever makes it to the table. I saw a video of the infamous Cubby station from the air taken in the last couple of weeks. The very same farm that is almost constantly attack for stealing all of the Darling flows........ The dams are dry.....grass growing on the bottoms. For all the blame, the lack of rain in the catchment never rates a mention like is is of no consequence. If the protesters accounts were accurate, the cubby storages would be brimming.
Posted by: Seina

Re: Streamflow Observation - 30/07/2016 23:48

I agree that rivers running dry can be a naturally-occurring phenomenon (assuming they are prone to it occasionally). If not from locals who have been living in an area for 50+ years, then certainly from data records, information about what's happened in the past can be eye-opening.
Posted by: teckert

Re: Streamflow Observation - 30/07/2016 23:49

Originally Posted By: adon
This used us huge amounts of stored water to flush the mouth in dry times when the mouth would have naturally closed is stupidity at its worst. Everybody keeps attacking cotton growers for wasting water when one of the biggest wastes is the lower lakes/Murray mouth. Over 1000GL are evaporated (wasted)just to keep it fresh. Double Sydney harbour!
More to flush the mouth.


This is inaccurate.
The mouth only closes at times of low flow. AT which point it is dredged. It is only flushed in times of high river flow. For example, the high flows in 2010-11, when South Australia received a peak flow of 94 gigalitres (GL) a day, provided a peak flow through the barrages of 75 GL per day, which was sufficient to scour the mouth and flush sand back into the southern ocean.
Posted by: teckert

Re: Streamflow Observation - 30/07/2016 23:55

Originally Posted By: adon
The only stupid decision in regards to them was this monumentally dumb idea of keeping the lower lakes (previously an estuary) fresh.


Also inaccurate to an extent!
They were predominately freshwater lakes, barring times when tidal inflows around the mouth and Point Sturt increased salinity in those areas, so it was a tidal estuary
This is substantiated by Aboriginal records, Charles Sturt's expeditions, and geological analysis
Posted by: Seina

Re: Streamflow Observation - 03/08/2016 17:36

Areas around Wangaratta VIC and to the near-SE of there have reached and been steady at moderate flood level since last night. Diamantina Lakes in Central-western QLD is also experiencing flooding of a similar magnitude. Source: Bureau.
Posted by: Seina

Re: Streamflow Observation - 06/08/2016 21:53

#1383957 -- It looks like Wangaratta was fairly close to the epicentre of the flooding in Victoria recently, given the warning/s issued by the Bureau in that time.

Also of anecdotal interest, some large ant tests are evident in the Central Adelaide Hills, though not sure how long they've been around; 2 nights in the last week have had sub-zero minima.
Posted by: Seina

Re: Streamflow Observation - 09/08/2016 14:20

Originally Posted By: -Cosmic- (naz)
Also of anecdotal interest, some large ant tests are evident in the Central Adelaide Hills, though not sure how long they've been around; 2 nights in the last week have had sub-zero minima.

More ant tests noticed; more sub-zeros.
Posted by: Seina

Re: Streamflow Observation - 17/08/2016 17:42

03/08/2016 17:36:
Originally Posted By: -Cosmic- (naz)
Areas around Wangaratta VIC and to the near-SE of there have reached and been steady at moderate flood level since last night.

About a week later:
Not sure what the chances are at this point, however GFS is showing the dewpoint equating to the ambient air temperature sometime around the 18th-19th of August, with maybe 20 mm or more. The water level of the Ovens River is falling very gradually (now below minor), but the last time moderate flooding occurred there was somewhere between 20-40 mm locally. After examining flow records locally (although comparisons are fairly dubious), stream flow seems to fall much faster and respond much quicker than originally thought, even with 15-20 mm 24-hour totals. This begs the question what could happen to the Ovens if a long or short-wave upper trough with enough leverage hits the area...?
Posted by: Seina

Re: Streamflow Observation - 18/08/2016 15:42

Now there are two of them [periods when the air temperature and dewpoint equate] -- one tonight-tomorrow, and another ~23rd-24th.
Posted by: teckert

Re: Streamflow Observation - 18/08/2016 16:45

source? wink
Posted by: Seina

Re: Streamflow Observation - 18/08/2016 17:25

I'll quote the original post next time if need be...

The source was GFS ready ARL.
Posted by: Seina

Re: Streamflow Observation - 18/08/2016 17:40

Originally Posted By: -Cosmic- (naz)
I'll quote the original post next time if need be...

The source was GFS ready ARL.

The coordinates were -36.35, 146.32 -- which were from Weatherzone!
Posted by: Seina

Re: Streamflow Observation - 18/08/2016 20:12

The surface low in the Bight is 1 hPa higher at it's centre (4 pm AEST) than the on the 9th (10 pm AEST).
Posted by: Seina

Re: Streamflow Observation - 28/08/2016 15:01

Observations for (VIC):

Originally Posted By: -Cosmic- (naz)
03/08/2016 17:36:
Originally Posted By: -Cosmic- (naz)
Areas around Wangaratta VIC and to the near-SE of there have reached and been steady at moderate flood level since last night.

About a week later:
Not sure what the chances are at this point, however GFS is showing the dewpoint equating to the ambient air temperature sometime around the 18th-19th of August, with maybe 20 mm or more. The water level of the Ovens River is falling very gradually (now below minor), but the last time moderate flooding occurred there was somewhere between 20-40 mm locally. After examining flow records locally (although comparisons are fairly dubious), stream flow seems to fall much faster and respond much quicker than originally thought, even with 15-20 mm 24-hour totals. This begs the question what could happen to the Ovens if a long or short-wave upper trough with enough leverage hits the area...?

19th of August 2016 [and as indicated herein]:

As recent 24-hour and since 9 am showers and rain continue (20-30 mm since 9 am) in North-Eastern Victoria, the water draining into the rivers and creeks (Murray-Darling Basin) from the southern Great Dividing Range, will increase [Ovens and King catchment]. The upper trough that has and is continuing to lead to showers and rain across much of South-eastern Australia and Mid-North SA seems likely to clip areas between Mt. Buller and Albury-Wodonga (Source: ACCESS-R +24 HRS, 1000 EST 20th of August – MSLP, THK, PRECIP). This may lead to further stream rises in the area – Flood Watch issued 10:07 am EST Friday 19th of August.

Wangaratta Forecast: issued at 4:30 pm AEST on Friday 19th of August, 90% chance of 6-20 mm today into tonight.

Originally Posted By: Bureau
Issued at 9:28 am EST on Saturday 20 August 2016
In the 24 hours to 9 am Saturday, rainfall totals of up to 43 mm have been recorded across the North East catchments. Showers are forecast for the rest of the weekend. Totals of around 5-10 mm are forecast for Saturday, mostly across the ranges, with an additional 10-20 mm on Sunday. Snow will fall above 900 metres today.
Stream rises are occurring in response to the rain and with the forecast showers, areas of minor flooding may develop across the North East catchments during the weekend.

Bold Added.

Originally Posted By: Bureau
Issued at 9:30 am EST on Sunday 21 August 2016
Stream rises are occurring in response to the rain and with the forecast showers, additional areas of minor flooding may develop across the North East catchments during Sunday and overnight into Monday.

130 mm in 3 days at Mt. Buller, yet minimal observed impact on more north-eastern catchment surface flows.

Potentially Sustained Moderate-to-Heavy Rainfall for Northern VIC/Western NSW:
Written 27th of August 2016:

Over the coming week (27th of August to 3rd of September) a series of long-wave-turning short-wave upper troughs with varying degrees of north-to-south temperature differences (warmer-to-cooler respectively) will traverse the southern edge of the country. These upper troughs appear to be related to surface higher-pressure ridges, yet are not solely dependent on them for north-south or west-east motion and change. The [surface] ridges are apparently more north-south at present, yet the upper levels continue to remain dynamic – changeable rather than stagnant. As a consequence of the difference in motions between upper and low atmospheric waves, one will tend to lag or lead the other (again, at present); the upper features moving more swiftly. Therefore, as a ridge (north-south orientation) approaches, say, SW WA, and interacts with an upper rossby-wave (clips it), the more southerly (stronger) winds on the eastern flank of the ridge will encounter first land and drier, warmer air, and secondly upper dynamics (such as a pressure and temperature gradient – both increasing). Additionally, the southerly – upper, polar – winds will be moving north, into the Indian Ocean, generating instability vertically as they near warmer waters/land. This instability in turn generates mixing, which would force the air temperature in the vertical down, hence moisture and cloud development.

If the upper trough (long- or short-wave) is cut-off at the surface by ridging, from the main southern-ocean rossby-wave, and the upper moisture has nowhere to go but east…with additional moisture being fed into the upper low from the west, it will intensify. This is a possible scenario given with ACCESS and GFS in that time.

Disclaimer: Not a substitute for professional advice.
Posted by: Seina

Re: Streamflow Observation - 29/08/2016 22:58

Regarding the potential rain period to the 3rd of September for North-eastern VIC, the Bureau's 4.30 pm AEST forecast update for Wangaratta is showing anywhere from ~20 to 60 mm during that period (the higher end of that range may mean thunderstorms).
Posted by: Seina

Re: Streamflow Observation - 01/09/2016 21:36

Originally Posted By: -Cosmic- (naz)
Regarding the potential rain period to the 3rd of September for North-eastern VIC, the Bureau's 4.30 pm AEST forecast update for Wangaratta is showing anywhere from ~20 to 60 mm during that period (the higher end of that range may mean thunderstorms).

60 mm already exceeded.
24-hour falls to 9 am 31st of August.
Ovens River.

Harrietville: 54 mm.
Bright: 51 mm.
Eurobin: 48 mm.
Mt. Buffalo Chalet: 104 mm.

River level at Wangaratta started rising again [8:15 pm EST, 31st]. Rains appear more widespread into upper reaches of Murray.
Posted by: Seina

Re: Streamflow Observation - 02/09/2016 23:04

More showers/rain tonight going by Bureau's forecast and warnings [North-eastern VIC].
Posted by: Seina

Re: Streamflow Observation - 03/09/2016 14:23

Originally Posted By: -Cosmic- (naz)
More showers/rain tonight going by Bureau's forecast and warnings [North-eastern VIC].

More reasonably heavy rain reaching the upper catchment areas of the Murray last night (to 9 am this morning), with 57 mm recorded at Dartmouth Lake (one of 3 sites with 50+ mm). Also minor and moderate flood levels reached in Central NSW.
Posted by: Seina

Re: Streamflow Observation - 04/09/2016 20:56

The final total for the week ending 3rd of September (per Bureau maps) was anywhere between 50-150 mm across NE VIC/NSW, with lesser totals across the continental interior. Streamflow level responses have been varied, be generally minor-to-moderate to-date (4th).

It may be of anecdotal interest that ACCESS +00 hrs and GFS +00 hrs (for 1000 EST, Friday 2nd of September) seemed very similar on MSLP, THK, DPT, WIND, 700 hPa RH, WIND, 500 TEMP, WIND, HGHT to those of +144 hrs prior to that time and date.
Posted by: Seina

Re: Streamflow Observation - 10/09/2016 00:12

"Moderate flooding is occurring along the Glenelg River."
[VIC; 8:39 pm EST]
Bureau.
Posted by: Seina

Re: Streamflow Observation - 10/09/2016 00:34

MINOR TO MODERATE FLOOD WARNING FOR THE MURRAY RIVER
Issued at 4:52 pm EST on Friday 9 September 2016
http://www.bom.gov.au/cgi-bin/wrap_fwo.pl?IDN36629.html
[Link may expire/update.]
Posted by: Seina

Re: Streamflow Observations - 10/09/2016 19:33

Originally Posted By: -Cosmic- (naz)
This is it in a nutshell:

Written 22nd of July 2016:
Hypothesis:
The local river responded (rose) after 19.2 mm of rain in the 24 hours to 9 am, 20th of July. Observations suggest most of the rise occurred after midnight [Bureau], meaning it took 3.5 mm of moderate-to-heavy rain to reach the response threshold. The maximum observation based soil moisture that can be replenished by water soaking in is about 34.2% [own estimate] - the rest is soil grains and aquifers. The estimated change in water level was 0.198 metres [own estimate], with soil moisture up ~1.047% from the previous day. Assuming a bell-shaped of about 60 mm distributed over a 5-day period, the maximum stream level height is approximately ~1.8 metres [2.1 metres observed 26/07/2016, 8:32:00 PM], with soil moisture increasing by another ~1.019%. This is enough for some flooding; the current estimated stream level is 0.775 metres.
The difference between the observed (estimated) soil moisture and extrapolated 5-day soil moisture may be due to the fact surface-water is still soaking into the ground across areas most affected, which has been observed. The fact it was/is still soaking in after another 19 mm suggest there less capacity in underground systems, hence more surface-water runoff potential. Water is not a very compressible fluid [1].
[…]
[1]: http://water.usgs.gov/edu/compressibility.html

[] – Removed.
Bold Italics Added – which has now been observed after 35.9 mm in less than 48 hours [ending last night].
Posted by: Seina

Re: Streamflow Observation - 12/09/2016 20:45

Originally Posted By: -Cosmic- (naz)
MINOR TO MODERATE FLOOD WARNING FOR THE MURRAY RIVER
Issued at 4:52 pm EST on Friday 9 September 2016

Written 11th of September 2016:

Steady major flooding has now started in the Lachlan Catchment NSW. I realise I’m not a weather forecaster, but I think people can at least be aware in the Upper Murray, Ovens and King River Catchments, as well as the Lachlan (possibly Loxton/Renmark SA), there is a lot of moisture moving downstream. In the next few days there is potential for the thickness and temperature disturbance lingering (anchoring) near Geraldton WA to contribute to more flooding/surface-water rises in those areas. The next upper 500-hPa trough from the SW is more likely to clip this disturbance. I’m also aware on the ACCESS-72 hour run from 1000 EST (date this was written) of what this might mean – higher flooding risk – for the Adelaide area if the gradients intensify accordingly.

Edit: the disturbance may have migrated south from near Java, in the Eastern Indian Ocean.
Posted by: Seina

Re: Streamflow Observation - 18/09/2016 19:17

Two gauges in NSW (Lachlan Catchment) and VIC (Wimmera) respectively appear steady at major flood level (Bureau).
Posted by: Seina

Re: Streamflow Observation - 22/09/2016 17:35

Originally Posted By: -Cosmic- (naz)
Two gauges in NSW (Lachlan Catchment) and VIC (Wimmera) respectively appear steady at major flood level (Bureau).

It [run-off] has been spreading across the inland lately [QLD, NSW, VIC].

#1386767 - Don't think it's over yet.
Posted by: Seina

Re: Streamflow Observation - 25/09/2016 11:55

Originally Posted By: -Cosmic- (naz)
Two gauges in NSW (Lachlan Catchment)

Now 6, with evacuation orders (Weatherzone News, 24th) frown .
Posted by: Seina

Re: Streamflow Observation - 27/09/2016 15:07

Re: Lachlan see WZ news.
Re: Approaching SA weather:

Based on outputs from an experimental rainfall model, assuming at least 25 mm falls midnight to midnight tomorrow (28th), anything more than about 87 mm to following day and stream flow in the upper/middle Onkaparinga may breach 2 metres (minor). 95 mm gives major.

This is not a warning; this is anecdotal. Stay safe smile .
Posted by: Seina

Re: Streamflow Observation - 30/09/2016 20:10

Originally Posted By: -Cosmic- (naz)
Re: Lachlan see WZ news.
Re: Approaching SA weather:

Based on outputs from an experimental rainfall model, assuming at least 25 mm falls midnight to midnight tomorrow (28th), anything more than about 87 mm to following day and stream flow in the upper/middle Onkaparinga may breach 2 metres (minor). 95 mm gives major.

This is not a warning; this is anecdotal. Stay safe smile .

88.4 mm recorded between 11 am, 28th and 9.30 am 30th. Minor flooding downstream visible 28th.
Posted by: Seina

Re: Streamflow Observation - 01/10/2016 13:35

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Re: Lachlan see WZ news.
Re: Approaching SA weather:

Based on outputs from an experimental rainfall model, assuming at least 25 mm falls midnight to midnight tomorrow (28th), anything more than about 87 mm to following day and stream flow in the upper/middle Onkaparinga may breach 2 metres (minor). 95 mm gives major.

This is not a warning; this is anecdotal. Stay safe smile .

88.4 mm recorded between 11 am, 28th and 9.30 am 30th. Minor flooding downstream visible 28th.

* The Onkaparinga River broke its banks locally in places, however the terrain gradient was not flat enough for flooding to spread significantly (thankfully).

The current local weir height (Woodside) is 0.42 metres (1/10/2016, 10.15 am CST). Last time the level reached minor flood level (prior to this event - 26th of July), it fell back to 0.19 metres in about 5 days. This time it’s barely a day, and dropped to only 0.42 (from ~2 metres), with more potentially significant falls forecast till Tuesday, implying a much more sudden response to rainfall rate changes.

Other creeks/rivers were/have also been affected in the region (per recent Bureau Flood Warnings).
Posted by: Seina

Re: Streamflow Observation - 03/10/2016 12:39

Terrain not making such a difference now...approaching major flood level if water upstream/rain does not abate frown . River flow velocity 5-10 m/s.
Posted by: Seina

Re: Streamflow Observation - 03/10/2016 19:42

Originally Posted By: -Cosmic- (naz)
Terrain not making such a difference now...approaching major flood level if water upstream/rain does not abate frown . River flow velocity 5-10 m/s.

Broke 1000 mm for the year earlier today.
Posted by: Purnong

Re: Streamflow Observation - 04/10/2016 18:37

I was in the Murraylands on the weekend and there is a fair bit of water coming down the Murray River
Speaking to a few of the locals who have riverfront properties and they are starting to get worried for flooding later in the year
Anyone wish to comment on the rest of the year for the lower Murray
Posted by: Seina

Re: Streamflow Observation - 04/10/2016 21:53

Hi Purnong,

December is statistically a time for "late rains" in the Central Hills not always, but often enough... don't know how that'd impact the Riverina. If we receive 200+ mm [in the Hills] before the end of December, all-time record for annual total [from what official statistics are available] will likely fall.

Interesting times.
Posted by: Purnong

Re: Streamflow Observation - 05/10/2016 17:08

Originally Posted By: -Cosmic- (naz)
Hi Purnong,

Interesting times.


I was thinking the current heavy falls upstream in Vic and NSW will have an impact along with the snow melt and any other rain for the rest of the year
Some people up there are starting to talk 1974 flood levels which were pretty major
Posted by: Seina

Re: Streamflow Observation - 06/10/2016 21:13

Originally Posted By: Purnong
Originally Posted By: -Cosmic- (naz)
Hi Purnong,

Interesting times.


I was thinking the current heavy falls upstream in Vic and NSW will have an impact along with the snow melt and any other rain for the rest of the year
Some people up there are starting to talk 1974 flood levels which were pretty major

Moisture from the Pacific Ocean can interact in the Mid-NSW/NE VIC region with plumes from the Indian Ocean when cut-off lows move inland. Warm SST currents travel from the Indonesian Through-Flow (ITF) from the Tropical North-western Pacific – cross-equatorial, bringing with them additional latent heat energy. Combined with warmer waters from a negative phase Indian Ocean Dipole (IOD), these can interact near Java, Indonesia, bringing additional moisture to NW WA coasts. This moisture then transitions to become a plume once it interacts with the northern edge of the westerlies (at the middle to upper tropospheric levels). These plumes encounter pressure, thickness (kinetic energy) and thermal temperature gradients as they move from coastal NW WA to coastal SE VIC. Near-stationary surface ridging will displace these plumes if it has the same alignment (i.e. NW-SE). As the westerly belt has been quite dominant, it can generate a “gap” across the Southeast, which means ridges will have difficulty maintaining a NW-SE alignment without eventually being pushed further east. The pattern was/is fairly dynamic*, southerly and/or sub-tropical, hence wet conditions in those areas.

* Dynamic as in changeable/more variability. Stagnant is like stagnating water or winds -- negligible change or motion.

Bold - I think whether or not 1974 levels occur this year in those regions dependents rather a lot on the frequency of moisture and its ability to rain-out.
Posted by: Seina

Re: Streamflow Observation - 08/10/2016 14:18

The longer-term forecast for NE VIC/Mid-NSW has an eerie look about it (GFS to 23rd of October, at the moment).
Posted by: Purnong

Re: Streamflow Observation - 08/10/2016 22:14

Originally Posted By: -Cosmic- (naz)
Originally Posted By: Purnong
Originally Posted By: -Cosmic- (naz)
Hi Purnong,

Interesting times.


I was thinking the current heavy falls upstream in Vic and NSW will have an impact along with the snow melt and any other rain for the rest of the year
Some people up there are starting to talk 1974 flood levels which were pretty major



Bold - I think whether or not 1974 levels occur this year in those regions dependents rather a lot on the frequency of moisture and its ability to rain-out.


Thanks Naz
The current flows into SA are at 40 ML/d and I heard on the radio today this is expected to increase to 60ML/d with low lying area's expecting to flood
Could be interesting times indeed if we keep getting more rain
Posted by: Seina

Re: Streamflow Observation - 08/10/2016 23:23

Note-of-Benefit:
Approaching rain activity (SA Central District) with estimated soil moisture sitting about 0.26 (noticeably high, down 0.05 from recent rain).
Posted by: Seina

Re: Streamflow Observation - 09/10/2016 14:40

Originally Posted By: -Cosmic- (naz)
Note-of-Benefit:
Approaching rain activity (SA Central District) with estimated soil moisture sitting about 0.26 (noticeably high, down 0.05 from recent rain).

By the look of the Bureau's revised forecast, for later today/tomorrow.
Posted by: Seina

Re: Streamflow Observation - 10/10/2016 21:20

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
Note-of-Benefit:
Approaching rain activity (SA Central District) with estimated soil moisture sitting about 0.26 (noticeably high, down 0.05 from recent rain).

By the look of the Bureau's revised forecast, for later today/tomorrow.

Glad to be inaccurate on this occasion smile -- 7.2 mm so far since 9 am yesterday.
Posted by: Purnong

Re: Streamflow Observation - 18/10/2016 18:35

And so it begins
Be interesting to see if these flows increase, 60 GL a day isn't catastrophic but will be a pain for some people

http://www.bom.gov.au/cgi-bin/wrap_fwo.pl?IDS20371.html

FLOOD ADVICE MESSAGE FOR RIVER MURRAY SHACK AREAS

The State Emergency Service (SES) advises that, as a result of the recent high rainfall, flows in the River Murray are increasing. Predicted water levels are likely to cause minor flooding in the shack areas between Cadell and Mannum.

Shack areas that are likely to be affected include Morgan, Brenda Park, Scotts Creek, Walker Flat and Bowhill.

Flows into South Australia are likely to exceed sixty gigalitres per day (60 GL/day) in two or three weeks time and are expected to remain high for several weeks.

SES advise that owners of shacks in these locations should follow their Emergency Flood Plan now.
Posted by: teckert

Re: Streamflow Observation - 18/10/2016 21:49

there's many that are saying into the 90's which would rival 2011. Some are even suggesting it will crack 100 GL
Posted by: roves

Re: Streamflow Observation - 19/10/2016 09:05

60GL is enough for yabbies to get going so im happy with that though would love to see it go over 100GL to really give the flood plains a good drink.
Posted by: Purnong

Re: Streamflow Observation - 19/10/2016 12:35

100 GL would cause some problems for sure, I think the 1992 levels were around 90 GL
Then again I read that 1974 was about 180 GL and 1956 was 300 GL so while it will cause low lying areas some problems there won't be widespread devastation
Posted by: Seina

Re: Streamflow Observation - 20/10/2016 20:09

The upper Murray may be expecting more rain - based on a look at the Bureau's Seasonal Streamflow Forecast to December. The same outlooks (October-December) for the North Para River at Penrice (SA) seem a little bit more than a curiosity (if it turns out that way), if I'm reading it accurately.
Posted by: Seina

Re: Streamflow Observation - 21/10/2016 20:32

Originally Posted By: Purnong
100 GL would cause some problems for sure, I think the 1992 levels were around 90 GL
Then again I read that 1974 was about 180 GL and 1956 was 300 GL so while it will cause low lying areas some problems there won't be widespread devastation

Where exactly are you getting these GL figures from smile ? A weir, a dam, where? I am unfamiliar with them.
Posted by: Seina

Re: Streamflow Observation - 21/10/2016 20:51

Originally Posted By: -Cosmic- (naz)
Originally Posted By: Purnong
Originally Posted By: -Cosmic- (naz)
Hi Purnong,

Interesting times.


I was thinking the current heavy falls upstream in Vic and NSW will have an impact along with the snow melt and any other rain for the rest of the year
Some people up there are starting to talk 1974 flood levels which were pretty major

Moisture from the Pacific Ocean can interact in the Mid-NSW/NE VIC region with plumes from the Indian Ocean when cut-off lows move inland. Warm SST currents travel from the Indonesian Through-Flow (ITF) from the Tropical North-western Pacific – cross-equatorial, bringing with them additional latent heat energy. Combined with warmer waters from a negative phase Indian Ocean Dipole (IOD), these can interact near Java, Indonesia, bringing additional moisture to NW WA coasts. This moisture then transitions to become a plume once it interacts with the northern edge of the westerlies (at the middle to upper tropospheric levels). These plumes encounter pressure, thickness (kinetic energy) and thermal temperature gradients as they move from coastal NW WA to coastal SE VIC. Near-stationary surface ridging will displace these plumes if it has the same alignment (i.e. NW-SE). As the westerly belt has been quite dominant, it can generate a “gap” across the Southeast, which means ridges will have difficulty maintaining a NW-SE alignment without eventually being pushed further east. The pattern was/is fairly dynamic*, southerly and/or sub-tropical, hence wet conditions in those areas.

* Dynamic as in changeable/more variability. Stagnant is like stagnating water or winds -- negligible change or motion.

Bold - I think whether or not 1974 levels occur this year in those regions dependents rather a lot on the frequency of moisture and its ability to rain-out.

A tropical disturbance (which veered south from near Java and became anchored between Geraldton and Perth WA, near-stationary) may have formed a blocking pattern for the SAM back before early May, which subsequently broke down after surface ridging (higher-pressure systems) moved more east, changing the prevailing wind direction. Just an idea, but food for thought smile .
Posted by: Purnong

Re: Streamflow Observation - 21/10/2016 21:17

Originally Posted By: -Cosmic- (naz)
Originally Posted By: Purnong
100 GL would cause some problems for sure, I think the 1992 levels were around 90 GL
Then again I read that 1974 was about 180 GL and 1956 was 300 GL so while it will cause low lying areas some problems there won't be widespread devastation

Where exactly are you getting these GL figures from smile ? A weir, a dam, where? I am unfamiliar with them.


They were just the historic flows that I read about somewhere
There is an excellent graphic of the current river flows and levels in the below link

http://livedata.mdba.gov.au/system-view
Posted by: Seina

Re: Streamflow Observation - 21/10/2016 22:46

Thanks for the link.
Posted by: Seina

Re: Streamflow Observation - 29/10/2016 14:39

Dewpoint temperature may exceed the overnight low in the next 3 days.
Posted by: Purnong

Re: Streamflow Observation - 04/11/2016 17:20

Flood advice given now for the lower Murray

http://www.bom.gov.au/cgi-bin/wrap_fwo.pl?IDS20371.html

FLOOD ADVICE MESSAGE FOR RIVER MURRAY SHACK AREAS

The State Emergency Service (SES) advises that, as a result of the recent high rainfall, flows in the River Murray are increasing. Predicted water levels are likely to cause minor flooding in the shack areas between Cadell and Mannum.

Shack areas that are likely to be affected include Morgan, Brenda Park, Scotts Creek, Walker Flat and Bowhill.

Flows into South Australia are currently 55 GL/Day and will increase to around 65 GL/Day during the coming week. They are expected to remain high into December.
Posted by: Purnong

Re: Streamflow Observation - 04/11/2016 17:23

Originally Posted By: roves
60GL is enough for yabbies to get going so im happy with that though would love to see it go over 100GL to really give the flood plains a good drink.


I read they are predicting 95GL by the end of December so its getting there

http://www.adelaidenow.com.au/news/south...cce0289177b145b
Posted by: Seina

Re: Streamflow Observation - 08/11/2016 20:49

Local [Experimental!] Model Output suggests Mallee affected near the 13th of November.

Units, deg C/d, deg C/d, deg C/d, mm, dir (3 pm), dir (9 am)
Date, Max =, Min =, dpt =, Rain, tmWind, tnWind,

[Output]
12/11/2016, 27.7, 6, 3.8, 0, N, N,
13/11/2016, 15.9, 8.5, 9.4, 26.9, E, SE,
14/11/2016, 27.2, 9.5, 9, 1.2, N, NNW

See wind direction.

smile
Posted by: Seina

Re: Streamflow Observation - 09/11/2016 22:57

The previous post contains erroneous data -- the date was not reset to 8/11/2016, and remained on a previous tested data set date. Experimental it is.
Posted by: Seina

Re: Streamflow Observation - 12/11/2016 16:20

The dewpoint rose sharply yesterday afternoon, the vertical profile of the lower atmosphere becoming quite unstable with surface heating (i.e. colder-air characteristics above a mixed, warmer surface layer). Earlier signs of severe weather from about 1 pm ACDT near Hahndorf. The pressure fell below 1000 hPa which suggested stronger surface troughing (uplift with mixing) and convergence. This was not helped by the extent of troughing all the way to tropical regions in the north. It may have generated a huge temperature imbalance north-south, as the thickness raised inland temperatures and drew in moisture from the west. Hail was not only possible, but became a reality.

Minor flooding and large (2-3 cm) hail observed from Glen Osmond to Aldgate.

As note of benefit, the current system may retrograde slightly to become temporarily near-stationary over TAS/SE Australia, bringing a narrower plume of concentrated, higher-humidity air from the deep south NE-wards, forcing near-surface temperatures down, and shower activity to persist for another day or so over these areas.
Posted by: Seina

Re: Streamflow Observation - 14/11/2016 18:00

Riverland fruit-growers badly hit by Thunderstorms 11th-12th November frown . Falls between 30 and 70 mm recorded over a 3-day period in hills area.
Posted by: Seina

Re: Streamflow Observation - 27/11/2016 14:05

Notes: 24th of November 9:10 pm ACDT [Updated from 23rd, 8:30 pm]
It has become increasingly clear what has been happening recently…

There now appears to be a persistent plume of higher 500-1000 mb thickness air from the tropics (Broome-Darwin region) migrating S-SE into the Australian continental interior, which is not only driving interior temperatures up due to sensible heat, but pushing the northern edge of the west-coast ridge, south – compressing it as it drifts east. This will not cause fronts to buckle because the western, drifting ridge (which narrows north-south when it reaches the higher thickness) is weakened. The NW-SE troughing and diffuse regions of tropical lower-pressure disturbance across the interior are able to interact with the southerly upper trough. 700-500 hPa winds and moisture from the south may contribute to this by anchoring (at 500 hPa) in the NE region of the compressed ridge. This is also a mechanism for tropical (700 hPa), interior moisture to drift down, hitting a large temperature gradient.

Compression means the pressure-gradient force becomes greater than the Coriolis Force/Effect. This can induce troughs.

If this continues, there seems a greater risk of more thunderstorm activity in the NE quadrant of the compressed ridge [Mallee/Riverland/SW NSW], plus isolated to scattered showers across SE Coasts. Also, areas adjacent Alice Springs may be a risk of significant weather outbreaks. These are humid sub-tropical conditions. The western ridging is acting as a catalyst.

This is valid roughly (+/-) 2 weeks from the 24th of November.

Again, these are my views, so I cannot guarantee their accuracy. I can however point in a reasonable direction smile .
Posted by: teckert

Re: Streamflow Observation - 27/11/2016 14:16

Think you are on the money there. Looks humid, thundery conditions for much of central and SE Australia from about the second week of December onwards.
Posted by: Seina

Re: Streamflow Observation - 28/11/2016 17:18

It was partially a precautionary note smile -- about the risk of significant weather outbreaks, hopefully not understating it.
Posted by: Seina

Re: Streamflow Observation - 03/12/2016 12:30

Dynamics have shifted slightly...however dew points are very interesting for next probable change -- ~ 18-to-20 range on ACCESS/GFS. That's a lot of moisture, I think.

Unless I'm mistaken, this moisture will (locally) be drifting off the eastern slopes of the Mount Lofty Ranges (NE-to-SW) with a north-westerly wind, because the higher temperatures are to the NE, lower, SW.
Posted by: Seina

Re: Streamflow Observation - 04/12/2016 11:52

19-20 C, near 90% RH.
Posted by: Seina

Re: Streamflow Observation - 06/12/2016 21:55

Originally Posted By: -Cosmic- (naz)
19-20 C, near 90% RH.

A note about humid sub-tropical conditions settling in, for the first event, with 6.6 mm to 2 pm that day.

Clarity: 18-to-20 probable/observed dewpoint range applies to end of forward 2-week period (i.e. 8th of Dec).
Posted by: Seina

Re: Streamflow Observation - 10/12/2016 15:19

Rewritten 8:35 pm ACDT:
It seems the southern-ocean 500-hPa troughs have been aligning to the north-eastern flank of the west-coast surface ridge, bringing with them milder temperatures due to travelling so far north (they gain latent heat), ...in the process they seem to be destabilising the northern thickness plumes (generating pressure gradients) and increasing mixing. 21.2 mm in 32 hours to 8 pm, 8th, not isolated stuff going by the area map for SA. There may potentially more on the way. A rough calculation gives:
Vapour pressure: 22.4 hPa (32/22, max-min Tuesday)
Dewpoint: 19.3 C
Surface barometric pressure: 995 hPa
Precipitable-Water: 25-40 mm.

The reference below may also help smile .
-------------------------------------------------------------

Post #1245515 - 03-03-2014 11:27 PM:

HypothesisIs Southern Australia becoming more Humid Sub-tropical?
Posted by: Seina

Re: Streamflow Observation - 17/12/2016 21:20

10-20 mm recorded in the Northern Flinders Ranges to 9 am, 15th.
Posted by: Seina

Re: Streamflow Observation - 21/12/2016 20:40

Originally Posted By: -Cosmic- (naz)
Rewritten 8:35 pm ACDT:
It seems the southern-ocean 500-hPa troughs have been aligning to the north-eastern flank of the west-coast surface ridge, bringing with them milder temperatures due to travelling so far north (they gain latent heat), ...in the process they seem to be destabilising the northern thickness plumes (generating pressure gradients) and increasing mixing. 21.2 mm in 32 hours to 8 pm, 8th, not isolated stuff going by the area map for SA. There may potentially more on the way. A rough calculation gives:
Vapour pressure: 22.4 hPa (32/22, max-min Tuesday)
Dewpoint: 19.3 C
Surface barometric pressure: 995 hPa
Precipitable-Water: 25-40 mm.

The reference below may also help smile .
-------------------------------------------------------------

Post #1245515 - 03-03-2014 11:27 PM:

HypothesisIs Southern Australia becoming more Humid Sub-tropical?

And now for part 2:

Notes -- Probable Rain Event 27th-29th of December 2016:

Written 18th of December 2016:
There is a chance a shallow upper (500-hPa) trough will drift across the Southeast of SA (south of about 33-to-34 degrees latitude; Ceduna, SA) overnight Monday into Tuesday (20th of December). A moderately strong ridge skirting SW WA (near Perth-to-Albany) is again being compressed – from the north and south. The northern compression involves the development of tropical features…venturing south from near Java. These include strengthening cyclonic activity and higher 500-1000 mb thickness plumes extending from Geraldton WA, to approximately Alice Springs. The strengthening cyclonic activity may significantly influence the direction and flow of [middle-level] moisture, dragging it away from the continental interior towards the WA coastline. This implies a possible convergence of moisture (surface to 700 hPa) between Geraldton, WA, and Alice Springs, NT (i.e. Ngaanyatjarra-Giles, WA). As the temperature profile is first stronger north-south (in the eastern interior) then north-south (in the western interior), this suggests more latent heat will be moving west rather than east across interior, feeding into the cyclonic activity. Where the stronger troughing is (Darwin to Geraldton) this can generate erratic wind direction changes, and compress the isobars running parallel. This, I think, is a recipe for increased storm activity near the WA/SA/NT border intersect.

Written 19th of December 2016:
As the cyclonic activity moves down the northern WA coast, towards Broome then Geraldton, it is likely to destabilise ridging in the region (NE-SW WA coastal fringes). This can give rise to more surface- and middle-level troughing (surface to 700 hPa), subsequently changing the wind direction and movement of moisture. During this time, it is likely the pressure-gradient force on the western edge of the cyclonic activity (Eastern Indian Ocean) will be greater than the Coriolis Effect (cooler ocean water, warmer inland). Additionally, the cyclonic activity seems likely to drag warm, drier air from the edge of the 500-1000 mb plume (Alice Springs vicinity) across the region where south-westerly winds have been more prevalent (Eucla, WA), thus reducing temperatures, and increasing precipitable-water. This wind-change dynamic has the capacity to drag lows and troughing inland towards SA as the central interior becomes cooler and more conducive to moisture build-up.

Written 20th of December 2016:
Places likely to be affected by this cyclonic-upper trough-inland wind and moisture dynamic would be those in the central south-western quadrant and Southeast of the country (i.e. Ceduna-Adelaide, SA). As the 500-100 mb thickness difference – temperature- and kinetic energy-gradient – increases with a [500-hPa] shallow-to-moderate upper trough intersecting 70-90% RH 700-hPa cyclonic moisture somewhere between Albany and Ngaanyatjarra-Giles, hot-to-very-hot winds would drift west from near NE SA. High-precipitation under extensive cloud-cover (severe thunderstorms, embedded with a rainband) seems likely to affect the Western-Central SA. Falls of 20-40 mm seem likely, isolated 50-100. It is difficult to tell how far the 700 hPa moisture can drift east before the impact of inland warmth becomes telling. One thing is telling though with both ACCESS and GFS models – the thickness gradient SW-NE is impressive for the 27th-28th:

Attempted Forecast Variables for the 28th of December 2016, Ceduna-Adelaide, SA (21st):
Dewpoint 22-24 C;
Air Temperature Max/Min 33/21 C.
Pressure: ~ 989 hPa.
Precipitable-water: 60-80 mm.
Sultry, thick cloud; CAPE 1200 J/Kg; CINH -250 J/Kg.
Posted by: Seina

Re: Streamflow Observation - 27/12/2016 11:30

80-90% confident of river rises to near/greater than minor flood level late 28th-early 29th of December 2016...east of a line Ceduna-Adelaide, SA!!
Posted by: Seina

Re: Streamflow Observation - 27/12/2016 14:15

Originally Posted By: -Cosmic- (naz)
One thing is telling though with both ACCESS and GFS models – the thickness gradient SW-NE is impressive for the 27th-28th:

The 576 thickness is likely to be around half way between the tropical feature travelling south, and the more south-westerly system.
Posted by: Seina

Re: Streamflow Observation - 29/12/2016 13:07

Woodsides annual rainfall record probably shattered, power out since 3 to 4 am yesterday not due till 8.15 pm, river almost minor 28th. Highest 6 hour rainfall that i know of. 891 am emergency radio broadcaster from nsw, what the....shocking winds during low peak. Forgot to mention....Damage.
Posted by: Seina

Re: Streamflow Observation - 29/12/2016 22:49

This is a bloody waste of time...unless someone else has had in excess of 36 hours without power, and wants to talk about what caused it, bye!
Posted by: bundybear

Re: Streamflow Observation - 30/12/2016 01:06

Originally Posted By: -Cosmic- (naz)
This is a bloody waste of time...unless someone else has had in excess of 36 hours without power, and wants to talk about what caused it, bye!


If I remember rightly in the last big flood we had here we were without mains power for 5 days. No phone for about 3 weeks. No mobiles for a week and a half unless you got lucky.

It took the council 3 days to realise there was even something wrong in the area as we are at the butt end to them and whilst they had rain we had flood.

After that it took them a couple of months to fix the bridge which was our route to town. Either had to head to the town to the north or take the very long way which is about 3 hours.
Posted by: Seina

Re: Streamflow Observation - 30/12/2016 15:08

So you empathise with people affected by the recent SA power outage/severe weather?
Posted by: Seina

Re: Streamflow Observation - 06/01/2017 15:22

Monthly Rainfall, Estimated Flow:- Northern Woodside, 2016 (in mm).
Month, (Highest Daily, Date), Estimated Streamflow Peak, Old [2013] Model (metres).

Jan-16 61.9, (32.5, 29th), 1.055.
Feb-16 22, (20.8, 2nd), 0.796.
Mar-16 38.9, (18.5, 10th), 0.635.
Apr-16 16.2, (6.6, 29th), 0.246.
May-16 182.3, (77.2, 7th), 2.564.
[9th of May river started filling from scratch due to pasture run-off.]

Jun-16 125.8, (32, 23rd), 1.218.
Jul-16 239, (34, 26th), 1.868.
[July--Highest monthly rainfall since January 2010.]

Aug-16 86.6, (16.7, 19th), 0.680.
Sep-16 208, (53.2, 29th), 2.285.
Oct-16 158.9, (38.3, 3rd), 1.759.
Nov-16 31, (11.6, 10th), 0.540.
Dec-16 133.2, (84, 28th), 2.885.
[Dec 28th--Quickest river rise observed since estimated records began.

Estimates Dec:

25th--0.04 m.
26th--0.20 m.
27th--0.36 m.
28th--2.89 m.
29th--1.74 m.

Actual Dec: BoM.

25th--0.05 m.
26th--0.29 m.
27th--0.08 m.
28th--1.74 m.
29th--0.29 m.]

Annual Rainfall: 1303.8 mm.
Average Annual Rainfall: Unknown for area, nearest longer-term official gauge 800-860 mm, 23829 (BoM).
Posted by: Seina

Re: Streamflow Observation - 10/01/2017 21:35

8th of January 2017:
The next potential date-ranges for reasonable (10+ mm) rain-bearing weather in an area Port Lincoln-Hawker-Renmark-Cape Jervis SA maybe the 12th-14th, and 17th-19th [of January]. Falls exceeding 10 mm have already been recorded in the state’s Mid North 9 am to 6 pm, 9th, in a precursor event.

12th-14th:
Estimated Max/Min: 25/21. Dewpoint: 15-20 degrees C.
Estimated Surface Barometric Pressure: 990 hPa.
Estimated Precipitable-Water: 20-40 mm.
Cloudy-to-Overcast (thick nimbostratus, stratus, cumulus).
Estimated rain-range: widespread 15-20 mm.

Estimated run-off impact: slight-to-mild [0.64 with 20 mm, up from 0.04].

17th-19th:
Estimated Max/Min: 21/15. Dewpoint: 8-15 degrees C.
Estimated Surface Barometric Pressure: 1000 hPa.
Estimated Precipitable-Water: 25-45 mm.
Partly cloudy-to-cloudy (stratus, cumulonimbus, altocumulus).
Estimated rain-range: unknown, possibly in a narrow band of activity.

Estimated run-off impact: unknown, dependent on the events of 12th-14th [minor flooding requires ~ 62 mm in 24 hours assuming 20 mm from the previous event].
Posted by: Seina

Re: Streamflow Observation - 12/01/2017 15:25

Originally Posted By: -Cosmic- (naz)
8th of January 2017:
The next potential date-ranges for reasonable (10+ mm) rain-bearing weather in an area Port Lincoln-Hawker-Renmark-Cape Jervis SA maybe the 12th-14th, and 17th-19th [of January]. Falls exceeding 10 mm have already been recorded in the state’s Mid North 9 am to 6 pm, 9th, in a precursor event.

12th-14th:
Estimated Max/Min: 25/21. Dewpoint: 15-20 degrees C.
Estimated Surface Barometric Pressure: 990 hPa.
Estimated Precipitable-Water: 20-40 mm.
Cloudy-to-Overcast (thick nimbostratus, stratus, cumulus).
Estimated rain-range: widespread 15-20 mm.

Estimated run-off impact: slight-to-mild [0.64 with 20 mm, up from 0.04].

Higher probability of moderate run-off - 1.1 to 2.1 metres.
Posted by: Seina

Re: Streamflow Observation - 12/01/2017 15:46

Anything more than about 63 mm in less than 24 hours and there looks to be a strong chance of low-lying flooding (modelled) in the Central Adelaide Hills of SA.
Posted by: Seina

Re: Streamflow Observation - 13/01/2017 19:34

Originally Posted By: -Cosmic- (naz)
12th-14th:
Estimated rain-range: widespread 15-20 mm.

Estimated run-off impact: slight-to-mild [0.64 with 20 mm, up from 0.04].

12.7 mm to 7 pm from 12 am. Not bad considering highest local falls were 20-30 mm smile . Minimal run-off.
Posted by: Seina

Re: Streamflow Observation - 18/01/2017 19:29

Originally Posted By: -Cosmic- (naz)
Originally Posted By: -Cosmic- (naz)
12th-14th:
Estimated rain-range: widespread 15-20 mm.

Estimated run-off impact: slight-to-mild [0.64 with 20 mm, up from 0.04].

12.7 mm to 7 pm from 12 am. Not bad considering highest local falls were 20-30 mm smile . Minimal run-off.

Minimal run-off estimate was 0.26 metres (the model underestimates stream flow peaks and overestimates troughs).

-------------------------------------------------------------

Some additional insight into why I thought the 12th-14th of January 2017 would be a light-to-moderate rain event, and why the 17th-19th (maybe now 18th-20th) could be more unknown:

Written 8th of January 2017 [Updated 9th]:
In addition to:

Quote:
Notes: 24th of November 9:10 pm ACDT [Updated from 23rd, 8:30 pm]

Extensions (and descriptive excerpt to the 18th of January):

Quote:
There now appears to be a persistent plume of higher 500-1000 mb thickness air from the tropics (Broome-Darwin region) migrating S-SE into the Australian continental interior, which is not only driving interior temperatures up due to sensible heat, but pushing the northern edge of the west-coast ridge, south – compressing it as it drifts east.

Quote:
This will not cause [cold]* fronts to buckle because the western, drifting ridge (which narrows north-south when it reaches the higher thickness) is weakened [west-east, the winds become more variable than for under the influence of a strong ridge]*.

Quote:
The NW-SE troughing and diffuse regions of tropical lower-pressure disturbance across the interior are able to interact with the southerly upper trough [next one perhaps by the 10th of January, with the main long-wave upper rossby-wave]*.

Quote:
700-500 hPa winds and moisture from the south may contribute to this by anchoring (at 500 hPa) in the NE region of the compressed ridge. This is also a mechanism for tropical (700 hPa), interior moisture to drift down, hitting a large temperature gradient [SW-NE]*.

Quote:
Compression means the pressure-gradient force [stronger, more variable winds]* becomes greater than the Coriolis Force/Effect [calmer, more settled conditions]*. This can induce troughs [see next quote below]*.

Quote:
These are humid sub-tropical conditions. The western ridging is acting as a catalyst [for trough formation, by allowing 700 hPa – low-to-middle level – moisture to converge near the 576 thickness interface]*.

Quote:
Written 18th of December 2016:
[…]
As the temperature profile is first stronger [with more sensible heat]* north-south (in the eastern interior) then north-south (in the western interior), this suggests more latent heat [for forming clouds]* will be moving west rather than east across interior [Clausius Statement of the 2nd Law of Thermodynamics]*, feeding into [...] [low/trough]* activity [nearer the West Coast]. Where the stronger troughing is (Darwin to Geraldton) this can generate erratic wind direction changes, and compress the isobars running parallel [lead to variable troughing and changes in wind direction where compression occurs]*.

Quote:
Written 19th of December 2016:
As the […] [low/trough]* activity moves down the northern WA coast, towards Broome then Geraldton, it is likely to destabilise ridging in the region (NE-SW WA coastal fringes). This can give rise to more surface- and middle-level troughing (surface to 700 hPa), subsequently changing the wind direction and movement of moisture [more S-SE than SE]*. During this time, it is likely the pressure-gradient force on the western edge of the […] [low/trough]* activity (Eastern Indian Ocean) will be greater than the Coriolis Effect (cooler ocean water, warmer inland). Additionally, […] [this]* activity seems likely to drag warm, drier air from the edge of the 500-1000 mb plume (Alice Springs vicinity) across the region where south-westerly winds have been more prevalent (Eucla, WA), thus reducing temperatures, and increasing precipitable-water. This wind-change dynamic has the capacity to drag lows and troughing inland towards SA as the central interior becomes cooler and more conducive to moisture build-up.

Written 8th of January 2017 [Updated 9th]:
In the case of the approaching NW-SW thickness-plume-upper-trough interaction (around the 13th of January), the change in wind speed to the west and south of West Coast low and/or trough formation [10th of January] can bring a mild 500-hPa plume from the south to interact the with a 500-1000 mb thickness plume (shifting towards SW WA, from about Geraldton). This interaction seems likely to pick up moisture in lower- and middle-levels of the troposphere as it drifts east – as the [southern] upper-trough (which is not embedded) meets the southern axis of the northern thickness plume (with the ridge to the immediate west). It will likely gain more ocean wind stress and momentum (because the surface-to-500-hPa temperature-gradient will be stronger, land-to-water). However, this can be tempered by the weak surface ridge over which the 500-hPa upper trough arcs to reach northeast. Surface trough activity is not unlikely between the two.

Of more interest rainfall-wise (though further out, the 18th of January) is an embedded upper trough in the main Southern-Ocean rossby-wave, which becomes annexed, capable of bringing heavy falls inland, Adelaide-Hawker-Renmark, SA. This is a fair way out, but noteworthy I think. This embedded upper 500-hPa would be unlikely without the main Southern-Ocean rossby-wave travelling west-east near the 13th.

Underline, []* Added. […] Removed.

Revision:
18th-20th:
Estimated Max/Min: 20/12 (18th), 31/14 (19th), 23/16 (20th).
Estimated Dewpoints: 8-15 degrees C (~ 14.5 (18th), 13.5 (19th), 16 (20th)).
Estimated Surface Barometric Pressure: 998-1004 hPa.
Estimated Precipitable-Water: 18-141 mm* (~ 51 average).
Partly cloudy-to-cloudy (stratus, cumulonimbus, cirrus, altocumulus).
Estimated rain-range: anything up to 50-60 mm (entire period).

*Possibly in a narrow band of activity. Please note falls may be heavily-dependent on where and when any rainbands/thunderstorms form.

Estimated run-off impact: 1.26 m (60 mm).
Posted by: Seina

Re: Streamflow Observation - 03/02/2017 17:21

Attempted Dynamic Weather Forecast: 28th of January to 8th of February 2017:
Variables:
Wind direction, Max/Min, Dewpoint, Rain Probability:
S-SE, 23/10, 9, Medium (20-60%) (afternoon, 28th).

There is a [surface] ridge in the Bight; a [surface] ridge in Eastern IO disrupted by lower-pressure system moving in a south-westerly direction. Inland WA troughing north of the 576-thickness is forcing winds off the equatorial-originating low [moving towards the S-SW] to interact with those related to a shallow upper-to-middle level (UML) trough moving up from the SW [between Eastern IO ridge and the one in the Bight]. The dewpoints with the winds coming down through the WA interior are much higher than those associated with the UML trough (below the 576-line), hence a strong indication of much higher inland WA absolute humidity in comparison. The thickness gradient (N-S) has a greater capacity for moisture to be retained inland (to the east of the migrating lower-pressure system) than with the SW UML trough. The wind-direction between these two features is around the spiralling low, towards the UML trough, which could form an arc of winds – S, to SW, to W, to NW – north of Perth (WA). The thickness [temperature] gradient means the moisture from inland WA can be directed towards the lower thickness region to the south of the 576-thickness line, which implies it could rain out (eventually), Geraldton-Perth-Albany-Eucla, in coming [28th-31st] days. The disruption of the Eastern IO ridge [by the migrating low] also implies the Southern-Ocean rossby-wave may compensate by allow more [shallow] UML troughs to reach Central SA.

As more UML troughs reach Central SA shores [due to the SW-migrating low in the Eastern IO], the higher-pressure system in the Bight can be disrupted in such a way as to allow a more dynamic, trough-based patterns to emerge. The displacement of the ridge in the Bight implies another ridge will attempt to take its place, from the west, in the process itself becoming compressed between the 576-line and tropical plume over the interior [WA/NT]. As UML troughs continue passage through (above the surface ridge in the Bight, in vertically), there may come a point when their arcing, and the changing in the 576-line, meets the very humid, warm air from the north [interior], bringing heavier falls to Ceduna-Port Wakefield-Nuriootpa-Loxton-Ouyen.

Written 31st of January 2017:
4th-8th of February 2017:.
Estimates (Adelaide Hills):
Date: Winds, Moisture Source, Max/Min, Dewpoint, Rain Probability (%).
4th, S-SW, Tm-Sm, 25/7, 4.3, Medium (20-60%).
5th, S-SE, Sm-Pm, 23/13, 12.4, High (60%+).
6th, SE, Pm-Tm, 23/9, 7.7, Medium (20-60%).
7th, ESE, Tm, 25/13, 12.2, High (60%+).
8th, E-ENE, Tm-Tc, 27/13, 12, Medium (20-60%).

Tm: Tropical Maritime.
Sm: Southern Maritime.
Pm: Polar Maritime.
Tc: Tropical Continental.

Estimated Surface Barometric Pressure: 1007 hPa.
Estimated Precipitable-Water: 12-35 mm on high probability days (~ 22 average per day).
Cloudy-to-overcast (stratus, embedded cumulus, nimbostratus, cirrus, altocumulus).
Estimated rain-range: anything between 30-50 mm (entire period), isolated 50-80.
700-hPa winds, Relative Humidity: Westerly, 70%+.

Surface run-off impact: minimal-to-slight, mostly soil moisture [although this depends on the rain-rate].
Posted by: Seina

Re: Streamflow Observation - 06/02/2017 18:42

38 mm, 12 am, 5th of February to 6 pm, 6th. Owen further in NW had 52 in 24 hours smile . Totals smaller further NE and SE. Not entire period over yet though.
Posted by: Seina

Re: Streamflow Observation - 21/02/2017 21:38

Bureau: As of 19th, 9 am, to 20th, 9 am, or later (2-3 days)

McArthur River Borroloola (514700, NT):
216 mm (24 hours) to 9 am (19th).
90 mm to 9 am (20th).
34 mm since 9 am, 20th (6.7 hours).
340 mm total (54.7 hours).
Minor Flood Level Exceeded (34.7 hours).

Roma AWS (43091, QLD):
28 mm (24 hours) to 9 am, 19th (local time).
29 mm since 9 am (10.5 hours).
57 mm total (34.5 hours).

Durah Homestead AL (542010, QLD):
36 mm (24 hours) to 9 am, 19th.
28 mm since 9 am (10.7 hours).
64 mm total (34.7 hours).

Strahan (97072, TAS):<