Page 52 of 52 < 1 2 ... 50 51 52
Topic Options
#1461329 - 09/04/2018 20:54 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7501
Loc: Adelaide Hills
Based on observations of broader to smaller scale weather dynamics in the Australian region [since about the 19th of March this year], the next probable significant [maximum] temperature change [fall] and increase in dew-point for the Greater Adelaide Area, seems to be starting within the next 3 days -- by the 12th. Any showers and/or rain needs to be steady-enough [overall] to avoid stripping top soil or causing landslides.


Edited by Seira (09/04/2018 21:03)
_________________________
Getting peace of mind and invoking kindness!

Top
#1462494 - 24/04/2018 22:29 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7501
Loc: Adelaide Hills
Originally Posted By: Seira
Based on observations of broader to smaller scale weather dynamics in the Australian region [since about the 19th of March this year], the next probable significant [maximum] temperature change [fall] and increase in dew-point for the Greater Adelaide Area, seems to be starting within the next 3 days -- by the 12th. Any showers and/or rain needs to be steady-enough [overall] to avoid stripping top soil or causing landslides.

Some top soil stripped from paddocks [haze] – due to stronger northerly winds leading up to the initial change (on the 12th of April), rather than from rain. Rainfall was about 38.6 mm over 4 days [14th-17th of April]; slight run-off. Most significant rainfall/shower period since Late November-Early December 2017 in the Greater Adelaide Area.

Many daily maximum temperatures in the vicinity of the Greater Adelaide Area [GAA] fell by 10-to-15 degrees between the 11th and 12th of April, while minimums maintained at about their pre-12th variability. A surface low with multiple associated NNW-SSE … (across the interior, towards Broome WA, and near Esperance) … and WNW-ESE (across the Tasman Sea, towards New Zealand) surface troughs formed near Kangaroo Island [KI] in front (east-of) an approaching longer-wave trough. This longer-wave trough was approaching from the Deep SW (south of Albany WA). The surface troughs [extending from the KI surface low] implied upper ridge conditions, with milder upper tropospheric temperatures, running from the upper-ridge centre – NNE of Adelaide – towards Queenstown Tasmania. This generated a somewhat unstable environment in which a narrow band of shower activity could pass mostly SE of the GAA.

The change in the maximum daily temperatures allowed water-vapour, siphoning along the NNW-SSE surface-trough/s, to drifting SSE along a temperature and pressure gradient. This was moisture moving from a higher pressure and temperature environment, to a lower one. Then uplifting to form cloud. This cloud consequently became thicker further SSE, and more convective in nature, generating mildly steeper lapse rates, with minimum temperature variability remaining mostly static.

This change in the maximum temperature [12th of April], combined with NNW-SSE-aligned surface troughs –provided the impetus for a change in the wind-direction from easterly (NE-SE) to more westerly. The eastward movement of the KI surface low would have allowed this wind-change to occur more than once along multiple trough-lines. These surface troughs were a convergent boundary, where the axis of the KI surface-low, also drifted from a previous front (moving towards New Zealand).


Edited by Seira (24/04/2018 22:30)

Top
#1465642 - 15/06/2018 00:05 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7501
Loc: Adelaide Hills
Local [Adelaide Hills] run-off is beginning to [measurably] respond to rainfall in the last few days smile .
_________________________
Getting peace of mind and invoking kindness!

Top
#1465746 - 16/06/2018 16:29 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7501
Loc: Adelaide Hills
Looks like a middle-to-upper-level shorter-wave trough has arrived in the Greater Adelaide Area; accompanied by a now-easterly-moving surface counterpart. Southern-to-Polar Maritime air-streams now mostly prevailing. Let's see how observations go overnight smile .


Edited by Seira (16/06/2018 16:38)
_________________________
Getting peace of mind and invoking kindness!

Top
#1467012 - 06/07/2018 21:49 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7501
Loc: Adelaide Hills
Originally Posted By: Seira
Looks like a middle-to-upper-level shorter-wave trough has arrived in the Greater Adelaide Area; accompanied by a now-easterly-moving surface counterpart. Southern-to-Polar Maritime air-streams now mostly prevailing. Let's see how observations go overnight smile .

Observations demonstrated the frequency and intensity of showers along the said air-streams were insufficient for additional, significant changes to run-off in the area…

In fact, nowhere across the country recorded additional, significant changes to run-off from "Below Flood Level" that are apparent, even with much higher falls across the Victorian Alps.

--------------------------------------------
Today (6th of July):

Potential for reasonable run-off overnight into tomorrow within the Greater Adelaide Area, that is by the 8th of July.
[Intense rainfall exceeding 20 mm recorded in the last 24 hrs. Local stream flow response evident.]


Edited by Seira (06/07/2018 21:58)
_________________________
Getting peace of mind and invoking kindness!

Top
#1467118 - 08/07/2018 20:19 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7501
Loc: Adelaide Hills
Originally Posted By: Seira
Originally Posted By: Seira
Looks like a middle-to-upper-level shorter-wave trough has arrived in the Greater Adelaide Area; accompanied by a now-easterly-moving surface counterpart. Southern-to-Polar Maritime air-streams now mostly prevailing. Let's see how observations go overnight smile .

Observations demonstrated the frequency and intensity of showers along the said air-streams were insufficient for additional, significant changes to run-off in the area…

In fact, nowhere across the country recorded additional, significant changes to run-off from "Below Flood Level" that are apparent, even with much higher falls across the Victorian Alps.

--------------------------------------------
Today (6th of July):

Potential for reasonable run-off overnight into tomorrow within the Greater Adelaide Area, that is by the 8th of July.
[Intense rainfall exceeding 20 mm recorded in the last 24 hrs. Local stream flow response evident.]

Rainfall, all ~ 37 mm of it since 12 am on the 5th, contributed to a mild-to-modest change in local run-off smile .


Edited by Seira (08/07/2018 20:19)
_________________________
Getting peace of mind and invoking kindness!

Top
#1467446 - 16/07/2018 20:50 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7501
Loc: Adelaide Hills
Another period of intensification of the longer-wave upper-trough system is approaching Southern Australia. Potentially rainfall in the range 10 to 40 mm+ between approximately Port Lincoln, Adelaide and Mt. Gambier SA. That's one way of looking at it anyway smile . It seems likely there will be a period before about the 20th-22nd [of July] when the day-night temperature range will moderate substantially, while the dew point remains high, relative to the overnight low. It's already on the Bureau's forecast by the looks of it.
_________________________
Getting peace of mind and invoking kindness!

Top
#1468220 - 03/08/2018 11:13 Re: Streamflow Observation [Re: Seira]
Flowin Offline
Weather Freak

Registered: 15/10/2017
Posts: 492
Loc: Pinjarra Hills, Qld
I think quite a bit of eastern australia (at least NSW and Qld) would like to see anything like the minor flows in Adelaide area streams seen overnight / today.

Top
#1468258 - 03/08/2018 23:20 Re: Streamflow Observation [Re: Flowin]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7501
Loc: Adelaide Hills
Originally Posted By: Flowin
I think quite a bit of eastern australia (at least NSW and Qld) would like to see anything like the minor flows in Adelaide area streams seen overnight / today.

My previous post is valid until midnight, 10th-11th of August...so hopefully something -- after the next significant upper-trough wave to reach SA coasts over the weekend / Monday -- will reach wide-enough east of Port Lincoln smile . Hopefully tapping some north-northeastern moisture streams.

Written 20th, Updated 29th: For Information
Dewpoint change observed 19th-20th [per previous post => 20th-22nd].
Potential Moderate-to-significant streamflow possible.
150 mm as upper limit => 30-40 mm 24-hour falls already recorded.
Extended to Eucla WA, and Omeo VIC.
Disclaimer: See previous.

A description of possible dynamics follows:

As the broader, shallower upper ridge over the NE-WA interior progresses further east, the next moderate-to-significant upper-trough wave peaks – in the Bight. This induces the upper-ridge to compress in the Tasman Sea [due to sustained wind gradients], thus forcing the upper-trough in the Bight to jack-knife and reach maximum amplitude through/near Eucla WA. An aggressive intrusion of surface-to-upper Southern-turned-Polar maritime air is propelled north into the interior, the upper-ridge in the east – near New Zealand – is dampened by the west-to-east progression of the westerly-belt. The jack-knifing of the upper dynamics forces the Indian-Ocean upper ridge SE.

Large swathes of the coastal SA plus peripheral countryside could experience very cold sub-10-degree days following the change evident on the map [6 pm ACST, 1st of August], moderately-humid and mostly wet conditions out to about the 10th of August. At the moment, at the highest end, the Bureau [per the 5.37 pm ACST forecast, 1st of August] had up to 50-100 mm by the 7th of August.


Edited by Seira (03/08/2018 23:26)
_________________________
Getting peace of mind and invoking kindness!

Top
#1468261 - 03/08/2018 23:54 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7501
Loc: Adelaide Hills
Thank you for your input to this thread Flowin smile .
_________________________
Getting peace of mind and invoking kindness!

Top
#1468422 - 06/08/2018 19:58 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7501
Loc: Adelaide Hills
There have been some significant stream responses between about Oakbank, Lenswood, Charleston in the Adelaide Hills, as can be seen in the flow meter readings for those areas on the Bureau's website [and by direct observations]. In the order of 60-70 mm has fallen in the last 1.5-2 days [highest rainfall totals], with more approaching / here now.


Edited by Seira (06/08/2018 20:03)
_________________________
Getting peace of mind and invoking kindness!

Top
#1468558 - 09/08/2018 20:07 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7501
Loc: Adelaide Hills
Originally Posted By: Seira
There have been some significant stream responses between about Oakbank, Lenswood, Charleston in the Adelaide Hills, as can be seen in the flow meter readings for those areas on the Bureau's website [and by direct observations]. In the order of 60-70 mm has fallen in the last 1.5-2 days [highest rainfall totals], with more approaching / here now.

Some 90 mm 12 am, 1st to 7th of August, 5.30 pm ACST.

Afternoon of the 9th:

It is very clear that some of the run-off from the previous [1st-7th] rain / shower periods has not fully soaked into the upper soil ... in fact, I think it's a bit of an understatement with puddles in lower-lying areas of the region, no where near soaking in; stagnant if anything.

Bureau forecast is currently [5.26 pm ACST] 95% chance of any rain, with 10 to 30 possible tomorrow...and a further 90%, with 8 to 20 Saturday. Therefore, streamflow may [again] respond significantly by midnight 10th-11th...deep into the Southern Australian Winter.
_________________________
Getting peace of mind and invoking kindness!

Top
#1468953 - 16/08/2018 20:43 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7501
Loc: Adelaide Hills
Originally Posted By: Seira
streamflow may [again] respond significantly by midnight 10th-11th...deep into the Southern Australian Winter.

Streamflow responded [again]...modestly peaking, reasonably early on the 11th.
_________________________
Getting peace of mind and invoking kindness!

Top
#1469176 - 19/08/2018 20:20 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7501
Loc: Adelaide Hills
It looks like streamflow responded quite abruptly and rapidly on Saturday [just gone] to a storm event in the early morning. A high probably of cause-effect anyway.
_________________________
Getting peace of mind and invoking kindness!

Top
#1469227 - Yesterday at 20:40 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7501
Loc: Adelaide Hills
Originally Posted By: Seira
It looks like streamflow responded quite abruptly and rapidly on Saturday [just gone] to a storm event in the early morning. A high probably of cause-effect anyway.

The storm in question was most likely moving in an NNE-ENE direction.
_________________________
Getting peace of mind and invoking kindness!

Top
Page 52 of 52 < 1 2 ... 50 51 52


Who's Online
0 registered (), 328 Guests and 1 Spider online.
Key: Admin, Global Mod, Mod
Today's Birthdays
Caldoche, David Obeid, desblair, Morrisjub, rmj007, rummy21, StormQueen
Forum Stats
29636 Members
32 Forums
23952 Topics
1495993 Posts

Max Online: 2925 @ 02/02/2011 22:23
Satellite Image