June 2001 Forecast Outlook, Discussion & Report Page

Victoria
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Victorian Weather Glass
Check out the Melbourne webcam if you want to keep up with the weather in Melbourne.
30 Clyve Herbert Interesting to see what appears to be a mid level disturbance over central Vic this evening, there are two decks of AC with the lower deck at about 10,000 moving from the south and an upper deck of AC around 13,000 moving from the north, although non active its worth watching this upper system over the next 12 hours.
25 Clyve Herbert Another synoptic/broadscale sized 'Hockey stick' cloud band (I'm sick of the description northwest cloudband!) approaching west Aus, similar but not as big as the one several days ago. Also a large field of cold air south of 40 degrees over most of the ocean south of Australia, looks like  the west and south of Tasmania will be the place to be for consistent
showers/rain, although conditions look better for the southeast of Aus this coming Thursday/Friday with  the possibility of a more active cold front.
25 Harald Richter Not many of the classic severe parameters were in place for this event.  There was little in the way of CAPE, lapse rates, moisture, cyclogenesis etc.  The only ingredient of note was the low-level shear.
25 Kevin Parkyn From all accounts so far the damage is consistent with F0. Spoke to a chap who lives about 300 metres from the damage site who has an AWS in his backyard. He'll be sending in the reports from his AWS this week hopefully. The signature from the 3-D radar shows a cell of deep-convection near Ballarat at the time of the incident. Middle level capping of most cells occured around 4km, however the cell in question managed to break this resistance barrier and shoot up to 6km, but only magaged this feat for about 10 minutes. Bouyancy was nothing spectacular, however the extra vertical extent probably allowed middle level winds to mix to the surface. I suspect that negative bouyancy played a part adding to the already strong WSW winds aloft (about 40-50 knots).

Directional and possibly speed shear existed in the low levels right near the passage of the front on which the cell formed. Consequently a short lived tornado is not out of the question, however the damage is consistent with that caused by straight line winds.
21 Harald Richter The severe weather folks on the 26th floor are examining the data. From watching over their shoulder it looks like:
* the "event" had virtually zero analysed CAPE
* the reflectivity signature of the convection (at all tilts)shows nothing outrageous
* the low-level shear was fairly large (I think aircraft data showed ~50 knots of flow around 850-700

I am not sure whether I would be able to separate strong straight-line winds from an equally strong surface circulation in the dark with rain present. The data certainly do not show a high probability of a "coldie", but the shear profile suggests to me that you can't rule it out either.
21 "Freak wind storm hits Delacombe" report from the Ballarat Courier of last night's wind damage.
21 Clyve Herbert The upper cloud band across the top end of the NT looks impressive, appears to be associated with a marked strengthening of the 500hpa -300hpa flow from the northwest which may be responding to major cyclogenisis west of NZ.
20 Clyve Herbert A small cold pool south of Adelaide on the north side of a fast moving low looks to be heading for the southern part of Tasmania, this low is interesting and may indicate a brief strengthening of the ridge over the western Aus Bight region, also a weak baroclinic cloud area over the top end has also moved rapidly south-eastward towards northwest QLD indicating a strengthening mid and upper flow in theta region may indicate an upper system over central QLD.
19 Clyve Herbert Its still interesting to see some tropical showers still ligering not far north of Darwin, but what's interesting is the tongue of mid level (alto stratus/altocu mix) moisture spreading south-eastward across the top end and coming ashore just south west of the Darwin region. Also a nice long wave trough building well west of WA with a low below 966hpa south west of Perth.

The present high pressure phase affecting Australia looks to be rather strong and should persist for most of the week. The long wave trough over the Indian Ocean is slow moving but rather strong, although lacks the moisture inflow from the tropics indicating the jet is further south, unlike last week's effort which saw the sub tropical jet dragging heaps of moisture from north of Australia. It looks as if early next week this long wave trough will encroach onto the Australian Mainland and if the following high ridges to south of 50 degrees it may indeed inject a reasonable cold air field   across the southeast of Aus: although its a little early to be sure about this
12 Andrew McDonald Front should cross Victoria tomorrow afternoon and cold air should extend throughout by Wednesday midnight and snowfalls on the alps should start sometime around midnight and then the altitude snowfalls start at should drop rapidly and IMO bottom out somewhere between 400-600m (in Victoria). Following the front we should see showers, local hail and thunder and possible sleet in the suburbs of Melbourne (given the timing of the coldest
air to be early Thursday morning and coninciding with the coldest part of the day I think this is quite possible).  Overall snowfalls for Victoria: The areas between 600-1000m should see between 5-20cm of snow, 1000-1200m should see some heavier falls of up to 30cm and I think the alpine resorts (inc. NSW ones) could see as much as 50-60cm from Wednesday night until late Friday (maybe continuing very sparesly Friday night) with the heaviest falls being on Thursday.  I wouldn't be surprised to see some road closures due to heavy snowfalls and black ice.  The road through the Black Forest will be a shocker on Thursday as will be the Black Spur and the Alpine road (both ways out of Mt Hotham) and probably also the roads to Mt Baw Baw and Donna Buang may be closed. 


Please remember that this is based on the model runs I saw this morning (briefly) and also past experience with systems such as this. 
12 Nick Sykes The models are continuing to strengthenen this cold outbreak with it looking more and more likely that a very sharp, cold outbreak will effect SE on Thursday. The new GASP run has 528 thicknesses for Victoria, and 850 temps, not far of -4, this is very cold, and I would expect snowfalls below 500m if this continues.  This sytsem is looking more and more likely to have precipitation with it, with Eastern Vic, and the Alps looking, the best, significant snowfalls, around 30cm, possibility of more are looking likely. AVN, NGP and MRF all support the extent of this outbreak, and been only 2 days out, looks very nice.

Looking at the latest sat pic you can see how this system will hopefully unfold, and why it has the potential to be very cold.

You can see the cut off low that formed over SW WA a number of days ago now slipping SE, this is been deflected by the very strong jetstream to the NE (the large cloudband over the SE and the high to the east. This low is effectively setting up a cork. What I mean is that this low will impede the movement of the front (to our SW) east. This low will end up south of Tasmania.

The cold air pool (do not fear about the way it looks now, this is more an effect of latitude and origin (the further south they originate, the colder, and often a grey appearance is present. The familar, bright white speckled appearance does not start to become evident until the cold air moves over warmer waters further north, generating instability, and then the bright white topped cold air Cb's) than anything, and it is now showing signs of entering a maturing stage)

With the cork in place the front/cold air now evident will have no choice but to be deflected to the north (by now the jet now over the SE would have moved out into the Tasman). If you look at the orientation of the front, it is horizontal!!! This means it is been forced north, generally also associated with a very strong southerly jet.
5 Clyve Herbert One would have to be forgiven if your interpretation of the sat pic for the Australian region especially the fringing tropics as being closer to summer than June, but has anybody noticed (apart from the very nice and active semi cut off over SA) the huge amount of tropical moisture lurking north of a mid latitude long wave trough west of Australia. A similar tropical moisture plume has been affecting the central Pacific for the past two weeks, worth
keeping a close look.
5 David Jones I am quietly optimistic that much of SE Australia will get a major rain situation, but with the progs - well - looking so down-right weird one can't be certain. One thing that has caught my eye with the approaching system is the very high dew points which are starting to show up over much of southern/central Australia - widely 11-15C. I doubt this system will be a flooding event (the baroclinicity across the system is relatively modest), but it looks like it could provide the first substantial rain over most of Victoria and western NSW for 3+months. BTW, also noticed that the thickness over northern South Australia are going to be marginal for snow/sleet on the higher peak (thickness ~544gpdm) - pity "no" one will be there to observe anything.
4 Clyve Herbert Check out the massive area of cloud west of Papua NG, lots of embedded CBs, although very poorly organised this region of cloud developed at the north end of a major long wave mid lat trough a few days ago and has been drifting westward very slowly. The only sign of organised upper flow is in the northward moving outflow anvils over the eastern side of the cloud mass. This area is worth watching to see if there is any interaction with the approaching long wave trough now advancing/stalling over the western half of Australia.
3 Clyve Herbert A moderate strength cold pool is advancing north-eastward from well south of WA, also some reasonable baroclinic areas over much of the western half of Australia. Look for vorticity around the western Aus Bight over the next 12 to 24 hours.
1 Clyve Herbert Things look better next week with what seems to be a major cyclonic phase moving into south-eastern Australia, with some reasonable chance of snow later in the week across the Victorian High country and Tasmania, might even get into the Blue Mountains - some good rain across Victoria too

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