Victoria - November 2001 Forecast Outlook, Discussion & Report Page



November 2001 Forecast Outlook, Discussion & Report Page Victoria
Date	Name	Information
.	.	Victorian Weather Glass
		Go to December 2001 Forecast Outlook, Discussion & Report page
17	Clyve Herbert	For those of you who actually like high pressure systems a king high pressure area south of WA is pushing towards the top 10% of expected highest surface pressure in our location (1038hpa), although this will be good for southeast Aus with a good slingshot of cold air coming up its east side and a cut off low forming near Adelaide, but check the pressure gradient between the low and the high: 1002hpa to 1038hpa.
16	Clyve Herbert	The low east of Thursday Island (which most of you have noticed) does show some interesting structure although a little on the weak side, there is better outflow towards the west with one almost detached band showing a nice anticyclonic curve through the Gulf of Carpentaria. The east side of the structure looks a little worse for wear with rather limited low to mid level convergence. Sea surface temps around the Gulf waters should be about 30C which is better than the Coral Sea about 27C +/- 1C, the system is still being steered to the westward which is good, well worth keeping a look at over the next 12 hours, also in the northern hemisphere there is a tropical storm well south of Hong Kong with rather good outflow to the northeast.
15	Clyve Herbert	Although a bit of a wish forecast the cloud mass over the northern Coral Sea does show some weak upper divergence and rather weakish low to mid level convergence,this development can be traced to northeast of Papua a couple of days ago.
15	Clyve Herbert	By last Sunday it was possible to see the area of vorticity developing over the Bass Strait region and near to southern Vic with mid and upper cloud moving in from the south on the western edge of the developing cold low.
14	David Jones	Thoughts on last weekend: The coldest air with the weekend's system past to the west of Tasmania, and crossed the west coast of Victoria near Portland, and so the effects were most pronounced in Victoria. On nearing Victoria, the sharp thickness trough substantially cut-off in association with the cyclogenesis which occurred near Bass Strait, and the coldest air eventually becoming "more or less" stagnant over Victoria, or more particularly showed a slow cyclonic rotation over the state...... for example the coldest air on Saturday night sat near Portland, on Sunday night northeast of Melbourne and Monday night directly over Melbourne. Going by the weekends news reports and rainfall figures, Victoria, and particularly southern Victoria between Cape Otway and Wilson Promontory saw the best of the action. RE this weekend... Still not sure what to make of this. It seems that the eventual outcome is totally dependent on whether the low currently developing over Western Australia is successfully captured in the westerlies by the cold front currently developing south of WA (the UK scenario) giving another strong cold blast in the SE (very similar to last weekends), and strong cyclogenesis near Bass Strait. This scenario looks as "interesting" in terms of snow/hail/thunder as last weekends, but most likely wetter as there is substantial moisture available to this system. The alternative scenario favoured by NOGAPS is for a failed capture, and a rather an anticyclonic change for the SE Australia. Yesterdays ECMWF sat between the two, while GASP is tending towards a significant system... I guess only time will tell. One thing to watch will be the possibility of heavy rain, as the catchments in southern Victoria are now saturated, and any significant rain could result in flooding (and on a positive note good inflows into Melbourne's dams).
14	Tornado	Information being collected at http://www.stormchasers.au.com/13_11_01.htm
14	Peter Creswick Tornado	It struck me that the warm bay waters would have been a perfect "breeder" with cold Bass Strait air coming in above from the S/SW. A few charts for the time of the event. http://www.theweather.com.au/uploads/Tor_Nov12_1500z.zip
13	Tornado	Summary - Aspendale Tornado Damage track ~2km long, 50m wide, SSW - NNE, approx 500m from Port Phillip Bay. Walls knocked down, glass & seating thrown a couple of hundred metres. Good directional shear in the lower layers, upper winds increased to 30knots & possible low level trough went through the area as the Fawkner Beacon recorded wind shifting from SW to NW & back to SW at the time. 60dBz at ~1-2km with tops ~4km. Rating: F0 - weak F1 Lasted 5 - 10 minutes Residents heard a loud wooshing sound, went out & saw a spinning funnel against the darker clouds. House next to a house damaged has an AWS - they are waiting on the reading from this. News reports courtesy Melbourne Age, Herald Sun & ABC Online PS: keep your ears peeled for further reports of a possible tornado yesterday morning in Port Melbourne being investigated atm.
12	Clyve Herbert	Just had a squall line move up from the south across the Bellarine Peninsular (Leopold) with some interesting bits and pieces hanging off the not bad looking shelf type cloud line ahead of the rain, a careful study of the infrared sat pic shows what appears to be a vorticity pivot point just east of King island, it will be interesting to see if any of the large infeed band over the Tasman will wrap around over the next 6 hours.
11	Jane ONeill / Andrew McDonald / Ross Buscall	Images of snowchase & Victoria today (report to follow)
10	Clyve Herbert	The coldest air pocket can be seen northwest of the 500hpa vorticity centre at 140east and 43south moving northeast, although there is some evidence of a 'wrap around' look to it as this area moves around the developing low south of Tasmania,still the overall field of cold air is rather large and southern Vic should start to see the affects later this afternoon.
9	Clyve Herbert	Vorticity can be seen at 140 east and 46 south near to the 500hpa cold pool advancing northeastward towards south-eastern Australia, not a bad field of cold air following either. I can't make up my mind, warm air storms or cold air storms?.....I will take what I can get!. Any way should see a consolidation of a dominant low east of Tasmania by tomorrow and the high moving to the Aust Bight will slingshot the cold air over Vic. On a tropo note, Typhoon Ling Ling is looking better all the time seems to be moving west northwest towards South Vietnam.
9	Harald Richter	A SW (surface) change has pushed through MLL by now (12.40pm), and I fear the MML sounding might end up suffering MTG's (Mt Gambier's) fate of a strong inversion around 800 hPa overlaid by a prohibitively warm atmosphere. A line of showers and weak thunderstorms is stretching from NNW of Lilydale to W of Seymour. The Seymour ``cluster'' is of reasonable size and has reflectivities exceeding ~50 dBZ (pink) on the 0.3 deg. 01:00 UTC scan out of Laverton. Ooops, back to 'yellow' at 01:20 (S of Seymour) with the cell N of Lilydale up to 'pink' - the nature of pulsing. I suspect that the line of storms is forced by surface convergence along a weak SW change that might have undercut those storms as per the 00:30 UTC VIC surface obs (the change seems to be ahead of the storms). That means the storms are elevated which will strongly limit their potential intensification. If you are reading this email from near one of those storms (and outside any outflow regions) and if you are experiencing W or SW flow, you might consider moving E or NE. One possible scenario is that the undercut storms die while new ones form (way) ahead to the E/NE seemingly making the storm jump eastward.
9	David Jones	I wouldn't want to be the one to jinx it, but after teasing all week with varying scenarios the models are attempting to converge in for the weekend. It now looks like the SE "could" experience a very significant out of season cold-outbreak, with thickness values over the Vic/Tas/SE SA/NSW progged by all models to approach 530 or even lower Saturday evening into Sunday. With the temperatures in Bass Strait and Port Phillip/Western Port Bay now well in excess of their winter minimum, such very cold air would support very vigorous cold air showers, thunderstorms and hail for Victoria, while snow levels should be significantly below the 1000m level in Tasmania and Victoria (and in the more extreme scenarios (GASP, US, and EC) should approach 500m. The biggest question mark on this system seems to be whether the cold pool will track NE (near central Victoria) or further west (near Mt Gambier).
8	Nick Sykes	Just down a fairly extensive run down of the models and it looks like there could be some storms develop through Victoria overnight and tomorrow. LI's are progged to be around -2 over the central Vic overnight and around -2 out east tomorrow. I like the possibility of something developing north of Melbourne and drifting south.
.	.	Melbourne Real Time Temperature Observations Graph Melbourne Real Time Rainfall Graph Port Phillip Bay Wind & Temperatures