ASWA Victoria - August 1999 Forecast Outlook, Discussion & Report Page

Updated 2124- 23rd August 1999 - J ONeill
August 1999 Forecast Outlook, Discussion & Report Page ASWA Victoria
Date	Name	Information
3	Andrew McDonald	NGP has forecast thickness to 528 Sunday morning and MRF has it down to 534 so I think we can expect some form of cold weather in the later part of the weekend and early part of next week. Snow WILL fall in large quantities from Saturday night until at least Tuesday dumping up to 50cm on the major resorts (maybe more) and up to 30cm on the lower resorts and I think the hills around Melbourne might even cop a dusting if we are lucky on Sunday night. Hail showers would also result and slight possibility of cold air naders if the wind profile hangs about like it is at the moment.
7	Jane ONeill	ASWA meeting
9	Laurier Wiiliams (NSW)	The US and Aussie global models are predicting a major cold outbreak across southern Australia, starting with WA on Wed/Thurs, moving to the east and intensifying over NSW/Vic/Tas on Saturday. There are some variations in intensity and timing, with NOGAPS the least spectacular, but both GASP and the MRF have thicknesses below 530 and 850 temps down around minus 5 well up into NSW on Saturday. More significant is the MRF prediction of a strong southerly jet at 300hPa to the west of Tassie on Saturday -- all good polar outbreaks have depth, and this feature bodes well for a snowy weekend. GASP has been quite consistent from run to run for the past 3 or 4 runs, too
10	Andrew McDonald	This coming weekend seems to be shaping up pretty well for some decent snowfalls. MRF, GASP and NGP all have varying degrees of intensity of the cold outbreak with thickness forecast as low at 528 Friday night. The worst outlook (as in the weakest) was for thickness getting down to 535 over Melbourne. This may drop the temperature slightly below 14C that has been forecast. The models indicated two cold fronts coming through - one Thursday and another, stronger one Friday. The 540 line is basically sitting along the line of the first cold front and the 530 line is sitting back a bit on the edge of the second front. If all remains as promising as it is now, there should be significant snowfalls right across the Victorian Alps and a fair way up the NSW Alps as well as the cold air stretches northwards. I believe there will be falls of up to 50cm at Falls Creek and Mt Hotham, 35-40cm at Mt Buller and up to 25cm at the lower Victorian resorts such as Lake Mountain and Mt Baw Baw. If the thickness does get down near 530 I think we could expect the snowline to drop pretty low - maybe down to 600m on Friday night. Hope this makes a few people happy!!!!
11	Rod Aikman	Bendigo rainfall figures for the rain event 8/9 &10th August 24 hrs to 09:00 8/8/99: 25.9 mm 24 hrs to 09:00 9/8/99: 13.3 mm 24 hrs to 09:00 10/8/99: 2.4 mm Total from this rain event: 41.6 mm
13	Rod Aikman	Last night (12/8) at about 18:00 a heavy shower passed over the southern suburbs of Golden Square and Kangaroo Flat, accompanied by small hail and thunder. At my house in central Bendigo, I only received 0.2 mm from the extreme northern fringe of the storm. After a frosty night (minimum 0.8 deg.), the morning started off mostly clear and sunny: by mid morning there was cumulus development; and by lunch time there were showers scattered about the district. During the afternoon cirrostratus started to invade from the west, thicken and lower, as a rainband (cold front) approached. There appeared to be cyclogenesis associated with this front, as the barometer fell, and the wind shifted to the north during the afternoon. The wind has now backed around to the south, and the rain band has cleared. (21:30)at about 20:30 there was a sudden increase in barometric pressure, and a sudden fall in temperature, indicating the frontal passage.
15	Dane Newman	Yesterday in the hills north of Noojee, about 100kms east of Melbourne. encountered patchy snow on the ground at about the 800 metre level, by the time we reached the highest point on the road 1100 metres the snow was about 15 to 20cms deep, it was also thick on the trees. The snow was falling off the trees everywhere, there were several quite heavy snow showers while we were there but snow flakes were small less than 1cm.
15	Jane ONeill	Ranger at Mt Donna Buang confirmed that the snow line was 800m.
16	Chris Gribben	The indications from the various models for the next system predicted to affect Victoria are quite interesting, but are certainly not classic cold outbreak indications at the moment. The most noticeable thing about this system is the way the models have it running almost west to east. MRF has tot-tots at 00z Friday at 45-50, A 70-80kn WNW jet stream, 850mb (about 5000ft) temps of between 0 and 2, thickness levels of around 538, precip water at 10-15 and 500mb temps of around -23C. This would indicate to me that this event is not going to be too intense and certainly not like the last system we had that gave us good snowfalls on the Alps. The 850mb temp is low enough for snow on the higher peaks but I don't expect the snow to reach low levels at this stage. Hail is possible but will most likely occur early in the morning should the system come through overnight Thursday. The jet stream is nice and strong but I don't think it will have an affect on this system apart from steering it in this interesting direction. Rainfall will be in the vicinity of 10mm with sparse falls to 20mm in my opinion.
20	Jane ONeill	Interesting cold pool in the Bight which has remained almost stationery (if not retrograde) for the last 48 hours whilst in close proximity to the southern edge of the upper jet. Continues to show signs of instability in the cold Cb's that appear on the satpic even though the pressure movement has the system filling in over the last 6 hours. If it moves landward, it may drift E - NE.
23	Clyve Herbert	Interesting altocumulus floccus & castellanus developing over Melbourne this evening reflecting middle level instability probably indicating radiational cooling of the 850 hPa level (approx). Suspect the possibility of middle and upper level trough developing over the west central & west of Victoria. These cloud patches are made more interesting by the atmospheric pressure of 1030hPa - if it was January we'd probably see thunderstorms tomorrow. Also interesting is the 300hPa sounding at Wagga this morning of -48C. Let's keep our fingers crossed.....