Victoria: Rain and Thunderstorm event - August 28th to 31st 2009

Looks like another possible event is on the way for the weekend and models line up for some rain to come in from the North West all have a trough and low coming down from the NW with some moisture attached to it with hot air stuck to the North of this band and cold air coming up from South of WA this band could thicken up nicely over SE Australia but few things have to go our way but at this moment I would say widespread 10-20mm is likely. EC has changed things round tonight though adding alot of wind to this system which I don't personally tend to like. Others thoughts?


John.

This system is certainly looking interesting. It looks like an almost classic late spring set up with a heat low getting caught in the westerlies. EC does have some very good rainfall with the system (about 30mm over 2 days around Melbourne) which would make it the biggest event for the year.... if it came off. Also some exceptional heat likely in the north - the guidance I've seen suggests 40C is a chance in southwest QLD.

What I like it establishes a few days of SW/W winds and frontal activity and this could keep showers going well after the solid rainband. It is a very good prospect.

Also EC late in it's run is beginning to warm up ahead of the next frontal feature which could be another thunderstorm producer, but that is way off.

BUT NO BLOCKS!!!!

Well would be more than welcome up here as it would be a good follow up. Got a nice surprise in the gauge with 12.5mm in the bottom. Having some more solid rain after this would be great and good for the crops.

Hey guys.

Well from what I have seen over the past month or so, the models have been fairly good at picking rain events, instead of the usual massive downgrade, they are only small or none at all, infact some upgrades. So I think this weekend and midweeks systems are both goers. Still speculating on how much, but will look at things closer tomorrow.

EC has some pretty decent rainfall out of this weekends system. Looks very widespread too so fingers crossed.

Looks like EC has backed off a little and clears us up quicker in the resolving westerly. But other models look ok still, so a good drop still possible.

Yeah the system itself I think has intensified with more rain even in the Ec scenario but the westerlies early next week are weaker now but thats ok as long as we get a good drop this weekend to compensate for it then another system by mid week next week I'll be happy with that

Latest EC has almost the "prefect" track on the developing low on Saturday with it developing very rapidly just southwest of Vic and then sliding through Bass Strait to be east of Tassie. UK, GFS and GASP are all very similar (UK is perhaps the best of the lot). EC has 28mm for the Melbourne CBD over Fri->Mon which is about as good as you'll see for that model. The central pressure drops by 20hPa in 24 hours so quite a bomb.

If it comes off as expected it looks like a quite general 10-30mm event to me (perhaps even a little heavier about the northern slopes). The upper trough also sharpens up which suggests the rain donut won't be such an issue and there should be some hefty showers behind the change.

This event could be nasty for the snowfields - 850T of 6C and rain, rain and more rain...

PS EC has dropped the westerlies for next week but now has a cut off low with a humid rainy north/northwest/northeast set up for the southeast.

Latest US indicating a rainband crossing the state and starting to increase it a little.

Fingers crossed your right DJ.

BTW the next system is crucial beyond the weekend.

Yes GASP, GFS have 15-30mm around for us down here, JMA 20-30mm, as you say DJ UKMet looks good too as does EC by the sounds of it. EC, UK and JMA have the most rain out of the models progged for this event especially through Central Vic and Melbourne so be interesting how this one turns out

If the progs continue the way they are I would assume BOM would issue a flood watch for the North East within the next 48 hours as alot of rivers are quite high there at the moment cos of the recent rains. 30-60mm is feasible up there through the higher NE catchments perhaps bit more, if these totals were to fall I would say few rivers will end up having some kind of flood warning again.

Well Bom is saying rain areas... first time I have heard that for a while. They are getting carried away though. Saying 10mm widespread with bigger totals around and especially in the NE.

Rain areas is appropriate and I would be very suprised if you did not get 10mm. Forecasts to me are spot on.

Sorry that was meant tot say NOT getting carried away! Haha bugger missed one word!!! Do you reckon there will be much chance of thinder in this or will rain be the go?

Personally no. Just a lot of cloud and rain. Will supress convection. Only chance will be along the upper trough.

Fair enough. Rain areas are better for widspread even rain over a large areas so people/places don't miss out. Better when you need rain. Thanks mate.

Looks on track to me both UKmet and JMA move the system right over us and give a good drop of rain 10-30mm. GFS has it slightly more North and Laps well thats just off the rails keeping the system well North. EC seems to be more inline with JMA and UK.

Keep an eye on next week as well models starting to throw around the idea of a low developing with colder uppers and some moisture about, the low be over Eastern or SE Australia GFS keeps it well North mainly in NSW while EC has it in our sweet spot over Bass straight or just East of us and slow moving as well but yeah alot of time between now and then but signs are suddenly looking up for better prospects of rain.

Sat loop over WA is starting to develop in the central parts and moving the the SE, Should see a fair bit out there by morning

12mm of rain in Alice Springs today which is Alice Springs entire August monthly average anyway thats a good sign for us over the coming days that there is now moisture in the Centre which will track SE over the next 72 hours

Hey John!! I got your SMS's but my phone died out on the road!! It is charging and will get back to you.

Some good signs early, the fact that the Alice has had it's average rainfall gives us hope. Can this system give us ours??

Anyhow a couple of days to go but nice to see those fronts coming through Sunday and Monday are a little stronger again. Gales and a few showers on both.

No Probs Karl thought that may of happend as you were out and about. Hopefully DJ can give us his input of how he see things as well soon

Really not much more to add Johnoo. Looks like a good solid event. EC has the low passing just southern of Melbourne at 996hPa (and dropping fast) at 10am Saturday. EC has 30mm Fri->Sun. UK/JMA/GASP look the same (almost the spitting image of the EC) and all have very good falls across pretty much the whole state (I'd expect LAPS to flip on the next run as it incorporates the latest GASP boundary conditions).

Looks like a good solid period of rain - personally can't wait!

I do reckon post rain band we could see some hefty showers and wouldn't rule out some cold air thunderstorms/hail with 850T down to about -2 to -3 on Sunday morning. BTW also exceptional warmth ahead of the front (won't impact most of us, but further north and east will get very mild). The 850T get to ~11C over northeast Vic Saturday morning. Could see some very rapid snow melt with that warm air and a warm rain.

After what I saw last night I now think anything is possible. Maybe if the warm/cold mix is big enough there may be the prospect of storms again upon the frontal passage moving through the metro area.

Melting snow plus decent rain equals very solid flows into rivers so might be seeing widespread flood warnings with this. Catchments are already wet so keep an eye on flows coming into dams. Sounds like the low is in a good spot for rain. IMO not the best for the far NW but OK for the rest(I like the lows to pass about Hamilton to Geelong for us to get the best rain).