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#1436297 - 07/10/2017 16:05 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7163
Loc: Adelaide Hills.
May be a chance of a [heavy-rain] storm or storms somewhere between Whyalla SA, Bourke NSW and Queenstown TAS, 10th-12th of October...with very high dewpoints!


Edited by Seira (07/10/2017 16:11)
Edit Reason: Details

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#1436598 - 10/10/2017 20:39 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7163
Loc: Adelaide Hills.
Originally Posted By: Seira
May be a chance of a [heavy-rain] storm or storms somewhere between Whyalla SA, Bourke NSW and Queenstown TAS, 10th-12th of October...with very high dewpoints!

7th of October 2017
A Snapshot of the Situation/Scenario smile :

SE SA, SW QLD, NW NSW, W VIC, W TAS – Rain/Thunderstorms Leading to Run-off.
10th-12th of October 2017:


An upper level disturbance travelling across the continental interior has interacted with tropical moisture coming from a surface trough down the NE QLD coastal fringe. This has recently led a higher-pressure ridge in the Indian Ocean to become elongated at a WNW-ESE angle [3rd-4th of October]. This elongation provides momentum for shorter-wave pockets of upper air (with cooler/colder temperatures) from the westerly belt. These winds are forced up the ridge’s eastern edge. Winds – along this edge – that reach far enough inland will lose moisture and dry out, before interacting with unstable air coming from NW-NE direction (from surface-trough/s and uplift, WA-NT). The Coral Sea may contribute as well – from E-NE.

As the WNW-ESE aligned ridge starts moving east, as well, the sub-tropical ridge becomes “/---\” shaped [7th of October], allowing a much larger gap between. This is possible because the NE edge of the WNW-ENE angled ridge interacts with middle-to-upper level moisture, leading that ridge to become weaker. This allows the longer-wave upper trough system through, into the Bight. 2-3 of these longer-waves (nodes) would be enough to have the ridge weaken further near the gap. Tropical-in-feeds from the ITCZ direction are then likely. These in-feeds would hit the NE-ridge axis, before being forced to convect with a southerly change moving inland towards the NT-SA-QLD border intersect.

Disclaimer: As previous.


Edited by Seira (10/10/2017 20:42)
Edit Reason: Grammar.

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#1437114 - 14/10/2017 18:05 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7163
Loc: Adelaide Hills.
Observations, 11th of October 2017:
After 16 mm of rain since midnight (rounded to nearest mm), run-off in the Adelaide Hills between about Crafers and Lobethal was clearly visible...after a somewhat dry period (no run-off causing rain). General falls of 15-30 have been recorded across the Hills [9 am to 8 pm CDT], with higher totals of 30+ mm recorded in NW interior SA. Lesser falls forecast in the next 24 hours.

SE SA/W VIC/NW TAS, 11th of October:
Falls of 10-20 mm have been recorded in the Lower SE, while falls [9 am to 9 pm local time] of 25-35 mm at, at least 2 locations in W VIC – Warrnambool AWS and Edenhope Airport – have been recorded. Falls up to 27 mm, 9 pm local time, NW TAS.

SW QLD/NW NSW, More Falls for W VIC, 11th of October:
Not yet – see second paragraph in previous post.
[SE QLD/NE NSW may be an extension of middle-to-upper level moisture moving ESE.]

Observations, 13th of October 2017:
Fall, Week Ending 13th of October were:
15-25 mm in SW VIC;
50-100 mm NW SA;
25-50 NW NSW;
50-100 SE Inland QLD;
and 50-150 NE Inland/Coastal NSW.
Additional falls of 25-50 SW NT/Far East-Central WA with in-feeds.

Source: Bureau.

Another surface low and trough in Inland Central QLD contributing more rainfall (25-49 mm last 24 hours) following passage of initial front, which clipped ITCZ moisture plumes along the way. This surface low and trough are clearly on the NE axis of the sub-tropical ridge:
[MSLP Analysis from 06:00 UTC, Thursday 12th to 24 hours later]

10th of October:

Quote:
Tropical-in-feeds from the ITCZ direction are then likely. These in-feeds would hit the NE-ridge axis, before being forced to convect with a southerly change moving inland towards the NT-SA-QLD border intersect.

Bold Added.

Validity period of previous post ended last night [13th-14th].

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#1437531 - 16/10/2017 16:49 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7163
Loc: Adelaide Hills.
Originally Posted By: Seira
SW QLD/NW NSW, More Falls for W VIC, 11th of October:
Not yet – see second paragraph in previous post.
[SE QLD/NE NSW may be an extension of middle-to-upper level moisture moving ESE.]

15th of October 2017:
Middle-to-upper level moisture (related to the middle-to-upper level disturbance's migration from the west) continues to feed into surface troughing from middle-level winds (originating from ITCZ), near SE QLD/NE NSW. The [middle-level] winds are blocked from venturing further south due to easterlies in circulation around the higher-pressure ridge off the coast of Sydney. The disturbance mentioned has a mild temperature-gradient, due to being forced ENE by the extent of ridge – losing steam because it is becoming cut-off. A relic of the initial movement from SW WA. However, with the near-surface temperature becoming milder (probably below 20 degrees), the Clausius-Clapeyron relation suggests the lower volume/temperature atmosphere will not be able to retain as much moisture (absolute humidity). This observation of lower-temperature influence is supported by the 576-thickness being further against the NE QLD coast, associated with the Sydney ridge – no clear in-feed, yet surface troughing northerly-to-southerly; the moisture is off the Coral Sea to the east. The next clear in-feed appears to be due (west-to-east) for another 3-5 days. The absolute humidity can be higher, just not at a higher (equatorial) temperature. The winds (near the surface) are from the east, therefore as they veer SW along the coastal trough features, they will cool, the near-surface air temperature and dewpoint coming closer together (probably below 20 degrees). The result is more cloud cover, yielding reduced CAPE within about 2 days; conducive to nimbostratus-type clouds.

100-200 mm may be possible locally N-NW of Brisbane at this time, with minor-to-moderate run-off [+24-48 hours].

Disclaimer: As with previous notes of this kind.


Edited by Seira (16/10/2017 16:55)

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#1437761 - 17/10/2017 22:14 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7163
Loc: Adelaide Hills.
Run-off Observations
48-hours out: Axis of heaviest falls approximately Mcilwraith-Bundaberg QLD -- Major Flood Warnings Issued (Bureau)!
Falls exceeding 350 mm Kolan Catchment [since 9 am 15th of October].
Potentially 50-100 more on way!
Got some serious diurnal/dewpoint changes going on out there!

Disclaimer: As previous. Follow Bureau’s warnings!


Edited by Seira (17/10/2017 22:23)

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#1438112 - 19/10/2017 19:24 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7163
Loc: Adelaide Hills.
Originally Posted By: Seira
Run-off Observations
48-hours out: Axis of heaviest falls approximately Mcilwraith-Bundaberg QLD -- Major Flood Warnings Issued (Bureau)!
Falls exceeding 350 mm Kolan Catchment [since 9 am 15th of October].
Potentially 50-100 more on way!
Got some serious diurnal/dewpoint changes going on out there!

Disclaimer: As previous. Follow Bureau’s warnings!

505 mm recorded at Springfield AL in SE QLD, from 9 am on the 15th to the same time (locally) on the 19th.

Major Flood Level [~ 11 metres] reached.

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#1439614 - 29/10/2017 17:09 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7163
Loc: Adelaide Hills.
Strahan-Queenstown area [Tasmania] will probably receive 20-40+ mm over the next 24-48 hours, with lesser totals [2-5 mm] in the coming week. MSLP will likely drop below 1000 hPa, thickness to 5400-5300 m, maybe lower, with the implication of hail. Mostly contributing to soil moisture.

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#1440120 - 02/11/2017 13:38 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7163
Loc: Adelaide Hills.
Chance of an impact on streamflow levels in WA, SA, inland VIC/NSW this month.

Disclaimer: As previous.

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#1440745 - 07/11/2017 19:20 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7163
Loc: Adelaide Hills.
Originally Posted By: Seira
Chance of an impact on streamflow levels in WA, SA, inland VIC/NSW this month.

An upper ridge seems likely to cross the Bight to be centred around Keith SA in the next 2-3 days.

Disclaimer: As previous.


Edited by Seira (07/11/2017 19:21)

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#1440948 - 10/11/2017 20:55 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7163
Loc: Adelaide Hills.
Originally Posted By: Seira
Originally Posted By: Seira
Chance of an impact on streamflow levels in WA, SA, inland VIC/NSW this month.

An upper ridge seems likely to cross the Bight to be centred around Keith SA in the next 2-3 days.

ACCESS-R’s Analysis Chart for the 500-hPa Temperature, Wind and Height, for 1100 am AEDT 9th of November showed an upper ridge approximately near Naracoorte/Keith SA.

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#1440988 - 11/11/2017 15:36 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7163
Loc: Adelaide Hills.
Originally Posted By: Seira
Originally Posted By: Seira
Originally Posted By: Seira
Chance of an impact on streamflow levels in WA, SA, inland VIC/NSW this month.

An upper ridge seems likely to cross the Bight to be centred around Keith SA in the next 2-3 days.

ACCESS-R’s Analysis Chart for the 500-hPa Temperature, Wind and Height, for 1100 am AEDT 9th of November showed an upper ridge approximately near Naracoorte/Keith SA.

Today till about the 17th. NW TAS included. Equatorial moisture near surface trough convective activity - thunderstorms/sultry rain and/or showers - with influences from upper-trough dynamics, and some wind disturbances. Slower-moving.

Disclaimer: As previous.


Edited by Seira (11/11/2017 15:42)

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#1441278 - 15/11/2017 23:10 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7163
Loc: Adelaide Hills.
Minor yet noticeable streamflow response after midday. Audible. Upper Onkaparinga.


Edited by Seira (15/11/2017 23:13)

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#1441319 - 16/11/2017 13:56 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7163
Loc: Adelaide Hills.
24-hour falls to 9 am, 16th of November: widespread 25-100 mm, 10-24 mm – see Bureau map.

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#1441995 - Yesterday at 16:57 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7163
Loc: Adelaide Hills.
Rapid run-off response may be possible over the next 24-48 hours across South-Central SA, with meeting of Southern Maritime (cold/wet), Tropical Maritime (warm wet) and Tropical Continental (warm/drier) airstreams.


Edited by Seira (Yesterday at 16:59)

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#1442031 - Today at 00:27 Re: Streamflow Observation [Re: Seira]
Seira Offline
Meteorological Motor Mouth

Registered: 27/08/2003
Posts: 7163
Loc: Adelaide Hills.
No disclaimer in previous post due to no feedback. Assumed by default from now on.

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