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#1442476 - 27/11/2017 17:33 Re: Streamflow Observation [Re: Seira]
Seira Offline
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Registered: 27/08/2003
Posts: 7584
Loc: Adelaide Hills
I think there's a system coming by the end of month, affecting the E to SE regions of the country. Question of magnitude of falls and how much the of current pattern/s will be disrupted. Dewpoints look to spike substantially, and absolute humidity with them.

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#1442499 - 27/11/2017 20:53 Re: Streamflow Observation [Re: Seira]
Flowin Offline
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Registered: 15/10/2017
Posts: 526
Loc: Pinjarra Hills, Qld
Agree 50 - 100mm in South Australia is a good dose of rain with runoff likely.
I have seen rain events in Queensland where more than 150mm absorbed and not showing signs of waterway flow at gauges... Albeit that does not happen often. And suchlike rain can bring runoff at the paddock scale that does reach river flows.
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Models are for estimating and gauges are for knowledge.

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#1442523 - 27/11/2017 22:51 Re: Streamflow Observation [Re: Seira]
Seira Offline
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Registered: 27/08/2003
Posts: 7584
Loc: Adelaide Hills
Was originally thinking 50-80 mm, SA/VIC/NSW/SE QLD, with significant run-off grading from remote chance to moderate, west-to-east.

Friday Max/Min, 18/13. (Bureau).

Surface Pressure: ~ 1002 hPa
Precipitable-Water: ~ 18 mm
Relative Humidity: ~ 70%
Rain: ~ 63 mm
Dewpoint: 13 C.


Edited by Seira (27/11/2017 23:01)

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#1442525 - 27/11/2017 23:04 Re: Streamflow Observation [Re: Seira]
Flowin Offline
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Registered: 15/10/2017
Posts: 526
Loc: Pinjarra Hills, Qld
Apologies I meant 50 to 100 mm in last event. Haven't looked at upcoming SA potential event, but if expected 50 to 80mm expected runoff would be a good chance
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Models are for estimating and gauges are for knowledge.

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#1442529 - 27/11/2017 23:14 Re: Streamflow Observation [Re: Seira]
Flowin Offline
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Registered: 15/10/2017
Posts: 526
Loc: Pinjarra Hills, Qld
When I looked at 23 nov 9am totals a few days ago for central to south SA I thought I saw 25 to 50, with one gauge over 50.
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Models are for estimating and gauges are for knowledge.

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#1442530 - 27/11/2017 23:19 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7584
Loc: Adelaide Hills
Originally Posted By: Flowin
When I looked at 23 nov 9am totals a few days ago for central to south SA I thought I saw 25 to 50, with one gauge over 50.

Rain gauges, yes, maybe two sites in that range (23rd Nov), streamflow gauges (i.e. recorded run-off) I don't know.


Edited by Seira (27/11/2017 23:24)

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#1442531 - 27/11/2017 23:41 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7584
Loc: Adelaide Hills
Post #1442523 temperatures refers to Adelaide/Hills only.


Edited by Seira (27/11/2017 23:43)
Edit Reason: Last Edit.

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#1442794 - 29/11/2017 21:59 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7584
Loc: Adelaide Hills
The system currently/beginning to form across SE Australia is likely to shift the synoptic pattern -- temperatures falling, and remaining noticeably low.

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#1442948 - 30/11/2017 18:15 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7584
Loc: Adelaide Hills
I'm going to wait for tributaries to start responding to rain for the approaching system, and draw conclusions from observations 30th of November to 2nd of December 2017 smile .

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#1443156 - 01/12/2017 17:58 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7584
Loc: Adelaide Hills
Originally Posted By: Seira
I'm going to wait for tributaries to start responding to rain for the approaching system, and draw conclusions from observations 30th of November to 2nd of December 2017 smile .

Ok, going to revise that.

NE VIC/SE NSW, especially west of the Ranges, I think is at a serious risk of flooding over the next 24 to 36 hours.

Going by ACCESS-R forecast dewpoints for the past 2 days for Saturday the 2nd of December, into the 3rd. For affected areas west of the Great Dividing Range, dewpoints are about 18-22 deg C. This implies a much narrower diurnal range – about 23/21, or higher, max/min. Estimated falls up to and/or exceeding 200 mm in that time frame. The air pressure likely 990-1000 hPa MSL adjusted. The upper trough is aligned SW-NE and anchored, as an offshoot, to the NE edge of the high in the Bight, plus to the main Deep SW trough system.

Disclaimer: Follow Bureau Warnings. Follow this precis at own risk.


Edited by Seira (01/12/2017 18:00)

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#1443776 - 04/12/2017 17:21 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7584
Loc: Adelaide Hills
System made it to about SE QLD's latitude Flowin smile . Even looks like it might have influenced latitudes as far north as Bowen.

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#1443832 - 04/12/2017 22:54 Re: Streamflow Observation [Re: Seira]
Flowin Offline
Weather Freak

Registered: 15/10/2017
Posts: 526
Loc: Pinjarra Hills, Qld
Yes Seira, the event of the last few days did have a wide influence from the south up to us in the sub tropical areas and further north. The initial rain front for us in SEQ on Saturday going into Sunday was uneventful but today's consolidation produced some good falls and streamflow. Reached minor flood levels at a few gauges.
For some periods it did have "atmospheric river like" look in terms of water vapour feed generally north to south and today south east across to NZ.🙃

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#1444179 - 07/12/2017 21:07 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7584
Loc: Adelaide Hills
Originally Posted By: Flowin
Yes Seira, the event of the last few days did have a wide influence from the south up to us in the sub tropical areas and further north. The initial rain front for us in SEQ on Saturday going into Sunday was uneventful but today's consolidation produced some good falls and streamflow. Reached minor flood levels at a few gauges.
For some periods it did have "atmospheric river like" look in terms of water vapour feed generally north to south and today south east across to NZ.🙃

Written the same day:

I see what you mean about minor flood level being reached. Fisherman’s Pocket TM fluctuated and is now rising, based on the readings (10.50 pm SA time), while Nagigan Road TM reached moderate flood level at about 6.30 pm local time, yesterday (3rd). Both near Gympie QLD.

Bureau are indicating a further 20 to 60 mm possible near Gympie, chance of any being 90% [8.20 pm AEST], maybe with a morning thunderstorm.

The streamflow response from the 30th to the 2nd/3rd was (and to an extent still is) having an effect at Seven Creeks at Kialla West, near Shepparton VIC. Still at moderate level.

…and yes, atmospheric rivers are interesting smile in the role they play in IWVT and where (in liquid form) the water-vapour ends up (on the ground).

The following day: Further falls recorded (50-150 mm range), near Gympie.


Edited by Seira (07/12/2017 21:08)

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#1456570 - 10/03/2018 22:13 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7584
Loc: Adelaide Hills
Hopefully there will be a mild south-westerly change around the 13th-14th of this month, and another about the 20th-23rd, with a higher probability of 10+ mm for SE SA smile [second wind change]. Also potential for further inland run-off through QLD, NSW, Alps with the second wind change.

Follow at own risk.


Edited by Seira (10/03/2018 22:16)

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#1457319 - 15/03/2018 21:47 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7584
Loc: Adelaide Hills
Originally Posted By: Seira
Hopefully there will be a mild south-westerly change around the 13th-14th of this month, and another about the 20th-23rd, with a higher probability of 10+ mm for SE SA smile [second wind change]. Also potential for further inland run-off through QLD, NSW, Alps with the second wind change.

Follow at own risk.

Update and Corrections:

Written 14th of March 2018 [Modified 15th]:

For those living and working in SE SA, the next likely [first for 2018] mild-to-moderate rainfall period with a chance of affecting run-off/soil moisture may be late March and into early April [between approximately 16th to 23rd]. A mild change with falling overnight lows in the Adelaide Hills – in the last 3-5 days, with the Sub-Tropical Ridge prevailing across the SE SA region, has led to an increasing onset of autumn-like conditions. A further vigorous SW wind change with a sharply-inclined axis, originating from the longer-wave westerly-belt, is likely (60-80%) to glance this region, bringing much stronger SW wind speeds. In the east, a [now] 1005-hPa low [Coral Sea] is likely to force N-NE winds across inland Western QLD, NSW, VIC and SA, with surface trough-like conditions prevailing between SE SA and more [SA-VIC] border regions. Much higher temperatures [35 C+] are possible east of this trough. This SW change will probably reach SE SA between the 17th and 19th, with the potential for thunderstorms in the said Western [QLD, NSW, VIC, SA] areas. Rainfall is likely to be of a convective nature initially, with more embedded convective activity in a stratiform cloud mix after the initial trough/s.

Disclaimer: As previous.


Edited by Seira (15/03/2018 21:50)

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#1458721 - 24/03/2018 13:20 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7584
Loc: Adelaide Hills
Rainfall mostly infiltrated the upper soil layers, or evaporated, with some run-off evident in concreted areas (in the city). Falls exceeding 10 mm were recorded in the Kangarilla Area of the Adelaide Hills. Further lighter falls (up to 2-3 mm) were recorded in the following 1-2 days [from the 18th].


Edited by Seira (24/03/2018 13:21)

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#1460776 - 03/04/2018 20:43 Re: Streamflow Observation [Re: Seira]
Flowin Offline
Weather Freak

Registered: 15/10/2017
Posts: 526
Loc: Pinjarra Hills, Qld
Originally Posted By: Seira
Rainfall mostly infiltrated the upper soil layers, or evaporated, with some run-off evident in concreted areas

That extract from your post Seira, is a key point in streamflow and runoff forecasting. There is notable uncertainty when "rainfall losses" are of similar magnitude to rainfall. When rainfall far exceeds "losses" such as what is infiltrated / "absorbed" or evaporation, runoff is easier to forecast, but streamflow at a location in catchment still has notable uncertainty related to catchment runoff accumulation and travel time for that flow.
_________________________
Models are for estimating and gauges are for knowledge.

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#1460960 - 04/04/2018 21:25 Re: Streamflow Observation [Re: Flowin]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7584
Loc: Adelaide Hills
Originally Posted By: Flowin
Originally Posted By: Seira
Rainfall mostly infiltrated the upper soil layers, or evaporated, with some run-off evident in concreted areas

That extract from your post Seira, is a key point in streamflow and runoff forecasting. There is notable uncertainty when "rainfall losses" are of similar magnitude to rainfall. When rainfall far exceeds "losses" such as what is infiltrated / "absorbed" or evaporation, runoff is easier to forecast, but streamflow at a location in catchment still has notable uncertainty related to catchment runoff accumulation and travel time for that flow.

To be quite honest the extract you quoted was an observation. I made an observation. If you think it's significant and stands out from other observations, then great smile ... it [the extract] was also connected to the post before it.


Edited by Seira (04/04/2018 21:30)

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#1461012 - 05/04/2018 15:48 Re: Streamflow Observation [Re: Seira]
Flowin Offline
Weather Freak

Registered: 15/10/2017
Posts: 526
Loc: Pinjarra Hills, Qld
All good smile . I took it as observation and an 'opportunity' to comment on the difficulties of streamflow forecasting. There is a fair bit on the forum about the challenges and uncertainty of weather forecasting. In the streamflow forecasting there are additional challenges such as the status of catchments as whole, and variability across the catchment.

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#1461149 - 07/04/2018 13:15 Re: Streamflow Observation [Re: Flowin]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7584
Loc: Adelaide Hills
Originally Posted By: Flowin
All good smile . I took it as observation and an 'opportunity' to comment on the difficulties of streamflow forecasting. There is a fair bit on the forum about the challenges and uncertainty of weather forecasting. In the streamflow forecasting there are additional challenges such as the status of catchments as whole, and variability across the catchment.

Yes, ok smile .

I would agree that there are a number of challenges (for lack of a more pertinent word) regarding forecasting the behaviour of the natural environment. I would think that a lot of the challenges would relate to or be connected with gaps in understanding the weather, climate or catchments. For example, if you were to ask anyone in the street, who was not familiar, what cirrus clouds are mostly comprised of, they may not know, and would have to guess. They may not even know what these clouds are...

The physics of the atmosphere, bar a few exceptions, makes it clear that they are mostly comprised of ice crystals, based on a number of known principles. This may or may not come as a surprise to an interested or curious onlooker, however it is essential understanding to the workings of the environment in which we live, work and play. It is also this kind of information and insight which needs to be conveyed if the differing levels of uncertainty are to be addressed adequately within the environmental science community – it is not all fun and games, even if they do have their place.


Edited by Seira (07/04/2018 13:18)

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