Updated 1135   - 30th October 1999 - J ONeill
October 1999 Forecast Outlook, Discussion & Report Page

ASWA Victoria
Date Name

Information
1 Andrew McDonald GASp seems to have some sort of trough lingering over us almost all week. Some days its really weak and pretty irrelevant but others its not too bad. Seems to be a lack of moisture at the moment though - 3rd Oct could be interesting....
5 Clyve Herbert From Upfield Railway station at 1300AEST, a line of Cbs spotted to the NE of Melbourne along the Divide.   Definitely *not* forecast...........what's happening?
5 Andrew McDonald From what I can gather from some models - which are pretty difficult to analyse at this time of year - a front will come through sometime between Friday night and Saturday night. Could be some embedded thunderstorms in the front and one model has a cold pool (thickness below 540) sitting in behind it so we could possibly see some cold air cells behind the front too.
6 Andrew McDonald Cumulus Humilus over eastern and north eastern ranges due to the lingering weak (very) trough extending down from NSW. Cloud direction from N to S. Possibility of afternoon showers in the NE and E today clearing this evening as the ridge of high pressure pushes into the state bringing a warmer northerly airstream hence the forecast of warmer temperatures over the next few days. As for today's warmer than expected temperatures I would say that the ridge is moving slightly faster than expected which could see temperatures exceed 25C tomorrow and again Friday where I think we could see our first 30C+ day for the season.
8 Jimmy Deguara (NSW) Well, the Vics have finally got the possibility of some excellent action particularly on Sunday but keep watch of Saturday. However, the ingredient they need is surface moisture and anyone that decides to chase along the dry air and moist air boundary - bingo!!! Hopefully, you also don't have too much mid-level moisture. You need extremely dry air in the middle layers which I think will happen with a NW wind!!!
8 Paul Yole (Horsham) 1430 - Altocumulus castellanus with virga falling seen in the Horsham area.
8 Ben Quinn (Qld) All models have a nice shortwave upper level trough moving through VIC on Sunday.. these shortwaves are the ones you should watch out for.. they can really turn an ordinary trough system into a major storm producing system..
MRF (Thursdays run) also points to overnight storms for Melbourne on Saturday.. continuing into Sunday, although maybe more likely east of Melbourne on Sunday..
It will be interesting to see how this all unfolds.. the winds throughout the atmosphere are nice and strong, so I  wouldn't be surprised at some organised activity.. if not severe storms somewhere in VIC from this system..
9 Jane ONeill ASWA meeting - 9am start
10 Dane Newman
(Kilsyth)		 A good sound and light show over most of Melbourne last night which continued on and off till about 4am. Most Melbourne suburbs received between 20 and 30mm, the city itself had 31mm, we got 21.4mm here in Kilsyth. Overcast with light rain here at the moment (11.30am).
10 Peter Matters
(Broadford)		 With the storm cells last night came 25 mm rain (recorded between 6.30 pm and 9.00 am this morning).
10 Nick Sykes
(Ashwood)		 Had 24.3 mm for the 24 hours.
10 Phil Papas
(Heidelberg)		 Had 22.5 mm on Saturday night
10 Paul Graham
(NSW)		 It looks like a pre-frontal rain band has helped raised dew points near the surface through W Victoria which in turn may be aiding the development of the storms there this afternoon. Otherwise, the NW stream is very dry and unstable near the surface. But most of the moisture has been advected from the Indian Ocean in the mid levels hence contributing to the rain band.Looks like it could be a storm chaser's delight this afternoon since the winds look favourable for supercells. Only it still may be a bit too dry...
10 Dane Newman
(Kilsyth)

Storm just clearing the outer eastern suburbs now good display of mostly cc lightning, some loud thunder only 1 or 2 seconds gap between thunder and lightning at its peak (about 10.30pm), heavy rain and some small hail. Also wind gusted up to 25 knots(estimated) at times.

11 Clyve Herbert Aurora australis to the south of Victoria 1am - 2.30am this morning with middle level cloud & occasional flashes of lightning.  This aurora (pink curtains) propagated from the south to the north. 
Dozens & dozens of frogs hopping around a street in Leopold just before 1am this morning - last time I saw this was in 1992 - just before one of the wettest summers on record!!!???!!!
11 Clyve Herbert Keep your eyes towards the middle / latter part of this week.  Trough developing over WA and good jetstream in SW WA at present.  Suggest rain & local storms Wednesday to Friday as the system moves east.
19 Clyve Herbert Suspect cold air advection at 600 - 500hPa over central Victoria, possibly indicating a cold pool. Destabilisation of lower and middle layers this morning with the possibility of small hail & the risk of isolated thunder.  This situation reflects cyclogenesis over the Tasman Sea intensifying the south to north flow over Victoria for a period today.  Most of the cold Cbs over central Victoria are topping between 18 - 20,000 feet with bases of 300 - 400 metres.  Possibility of a cold pool developing over central Victoria in the vicinity of Cb cluster, but it's more likely to drift NE and be absorbed in the developing low over the Tasman.
20 Andrew McDonald We may get some decent action Friday with 850 temps dropping to -5C and thickness to about 533 and LI's close to 0 at the surface (probably below 0 at 700mb).  I wouldn't be surprised if the forecast for Friday changes to showers with local hail and thunder in the south.  Snowfalls down to 1200m Friday night. 
20 Clyve Herbert Early prognosis: Strong high building Thursday through Friday in the western Bight area.  Trough and front moving through Victoria during Thursday afternoon / evening.  The present high pressure over Victoria will collapse.  Risks of: major cyclogenesis as the strengthening high in the Bight accelerates cold air north eastwards across SE Australia resulting in cyclogenesis probably E of 145E between 35 & 40S.  This may result in good rain situations developing in areas E of 145E & south of 30S with potential risk E of 142E.   Either way there is a potentially strong risk of cold air shower activity across southern Victoria Thursday through Friday. (NMP)
20 Nick Sykes It's looking like a late season cold outbreak, the sat pic animations show the front pushing up nicely from the SW and a nice pool of cold air is evident. Look out for some cold air Cb's.
20 Andrew McDonald Friday 22nd. -   cold air cells - not that good in terms of wind profile but we might get some small hail and thunder.  Upper low possible.
Monday 25th/Tuesday 26th. - Not quite sure about this as it is a fair way off but the potential is there for weak to moderate thunderstorms.
Saturday 30th - Once again a long way off but the potential is there for a nice trough and associated upper cold pool.
Scale is as follows:
Weak TS = thundery showers, thundery rain.
Moderate TS = moderate winds and rain associated with TS
Strong TS = hail, winds, heavy rain (but not quite severe)
Severe TS = non-supercells
Very Severe TS = supercells
21 Clyve Herbert Lightning SW of Dandenong 1840AEST
21 Jane ONeill Lightning NW of Lilydale 1849AEST
22 Andrew McDonald Possible funnel sighting at 1240AEST on NW quadrant of Cb that passed to the east of Melbourne CBD. (photos coming)
22 Chas Osborn Strahan (Tasmania)
Showers overnight and this morning some with soft hail. Current temperature 12 noon EDST 10C. The wind was calm this morning but has now picked up from the SW. Hobart had a noon temperature of 8C with reports of sleet in some suburbs. Snow reported down to 600m with a forecast for more this afternoon and tonight. The east coast is expecting rain from a low that is developing off the mainland.
23 Clyve Herbert Interesting observation at Leopold this morning. Barometer dropped 3hPa in 1.5 hours. Strengthening SE to 40-55kmh. Band of cirrus advancing from the north.  Low level glaciating cumulus showing freezing level at ~1200m. 
Suggest upper level disturbance over W-NW of the state.  Risk of major cyclogenesis continuing over SE Australia & becoming complex.

Potential: moderate-heavy rain east of 145E, possibly to 144E & south of 35S.  Risk of flood precipitation over the SE coast and eastern Victoria in the next 24 hours. Heavy snowfalls possible over the Alps in the next 24 hours. (NMP)
26 Clyve Herbert Cold air Cb's developing across southern Victoria this afternoon may generate 1 or 2 isolated thunderstorms.

Risks: brief squalls with isolated small hail especially in coastal areas.  Between midday & 2pm, isolated lightning discharges detected on hand held lightning detector (Sony) at Leopold, probably originating over Bass Strait.
26 Andrew McDonald Greensborough - 1505AEST - pea sized hail
26 Nick Sykes Ashwood - 1600AEST - small cell just moved over my house bringing a brief squall with heavy rain and a bit of small winter type hail. Plenty of cold air Cb's over southern Vic as an upper level trough moves through. Radar is showing plenty of cells around and this is backed up by sat pic which shows a well defined cold air pool over southern Victoria.
27 Clyve Herbert Increasing instability in lower and middle layers as a weak front approaches.  Risk of isolated thunderstorms between 1800 & 2400AEST.
28 Andrew McDonald (0748) Saturday 30th Oct - BoM are seeming pretty certain about these thunderstorms supposedly developing in all district so on that note I will definitely go for thunderstorms but the intensity is hard to pick as the models are all pretty different.  A lot depends on the timing of the trough/front.  Temp is forecast to go up to 26C so there will definitely be some heating around and hopefully some moisture left behind by that front (due Friday morning). At the moment I'll go for weak-strong thunderstorms but i may change this later depending on the other models and their wind profiles.

Wednesday/Thursday 3rd/4th Nov - Still a fair way off but some models are suggesting a very nice low pressure system moving down from SA right over us directing moist NE'ly over us.  These are sometimes great thunderstorm producers - if not for us for the people in NSW.  At the moment I'll go for weak - strong thunderstorms.  If the models remain the same I think we could quite possibly see some severe thunderstorms from this but I will watch the charts later in the week to see if i need to upgrade.

Saturday 6th Nov - If the low mentioned above intensifies as it slips SE'ly we could quite easily see some pretty cool air get sucked up in SW quadrant of it resulting in some cold air Cb's Saturday and Sunday morning.  I can only put weak - moderate thunderstorms on these for now but i will reassess the situation at the time draws nearer.
28 Andrew McDonald (1930) I think we'll be lucky to get weak-moderate storms across the whole state on Saturday ....little heating forecast now....LI's are apparently not negative (according to AVN and MRF) and CAPE is not great either. I might leave it until tomorrow to change it though. Next week we should see either a nice outbreak of STS or a decent heavy rainfall event - followed by a nice cold outbreak.
29 Clyve Herbert Large cloud mass moving from South Australia SE towards Victoria.  Cold front moving NE through the Bight.   Potential for interaction between cold front & cloudmass bringing moderate to good rain to Victoria on Saturday.  Best falls likely along the northern divide, central / west Gippsland & NE high country.  Risk of storms more likely in the far north & NE country at this stage.
30 Clyve Herbert Interesting flow pattern in the middle level cloud over south/central Victoria this morning showing orientation from 350deg. Low level cumulus developing in the broken patches running from 010deg.   Signs of vorticity over W Victoria, although weak.

Early clear patches may induce isolated storm activity.   Extensive upper & middle level cloud may dampen activity however. Trough & cold front to the west may trigger isolated activity with low & middle levels being quite moist.

Back to MSC