Victoria: Rain/Storm event: 29th Nov - 5th Dec (Analysis)

[mick]

The birds are scattering like crazy here. Its on its way thats for sure. I suspect this time tomorrow it wont be such a pleasant evening, the light is superb. The air over us is crystal clear compared to everything else we usually get even the southerly as that is too moist. Could clearly see the paddocks in the dandenongs from 60 k away this arvo, no humidity at all about down here. Dont get such a crisp view often, maybe once a year everything lines up.

[Anthony Violi]

Ec is coming around Jake, wont go into Southerlies. High is too far South and another inland trough will be dipping down quickly as GFS suggests..

Expect EC to go all in, in the next few runs.

[Jake Smethurst]

Ah yes I see what you mean Anthony. High is a bit far south. Will allow a new trough to push in as per GFS. Will be interesting to see what models have in the next few days and obviously as we get closer. Lots of cold air to play with ....

[mick]

Amazing sunset atm.

[I_Love_Storms]

There we go, our trough is back!

[Meso]

Can anyone explain the current weather situation in a bit more detail for those of us who aren't quite up to speed on these things? The main thing I want to know is, howcome the trough/low and all the weather are coming across from the east atm, when 99% of the time a low will just spin up out of the bight and come in from the west of the state? Is it because it's formed over the top of us or something?

Sorry if the answer is fairly obvious, but this is something I haven't seen (on this scale anyway) since I really begun learning more about weather, but I am finding it fascinating.

[Rivergirl]

Yes fantastic sunset, took lots of pics Last night was lovely too. Whenever you get those wispy clouds in the sky like last night they go pink after the sun sets.

I'm sure I'll love the DVD Dean

[stevco123]

Just having a look on the radar, is that rain band to the north east of melbourne likely to come here.it looks like its heading straight for us.its weird to see so much rain coming from the east instead of the west.

[Jake Smethurst]

Hi Meso. There is no such thing as a silly question.

What we have is a trough (the same trough that caused the weekend rainfall) currently sitting roughly right up through central Queensland, extending south over New South Wales and into central Victoria at the moment. Near or attached to this trough is an upper low pressure system, to Victoria's northwest. These are causing east to northeast winds (fairly obvious) which as a result is increasing the moisture profile across Victoria and the eastern states. Due to the trough and upper low, steering is actually out of the northeast or east, so general flow of showers/storms/rain has been towards the southwest or west, as seen tonight. It is the upper wind profile which is resulting in the rainfall coming out of the northeast. Does this explain things for you ?

The trough is retrograding further westwards to near the SA/VIC border from tomorrow, so showers/storms will be possible statewide from Wednesday, with the chances of them increasing through the week. We will probably see rain areas similar to tonight on and near the ranges during the next few days late in the days thanks to high moisture levels.

[Karl Lijnders]

I think that any day is still likely to give some pretty decent storm activity across the state, but the peak days seem to be Thurs/Fri/Sat then early next week. Models look plain crazy for next week with some hinting and lows and cold air, LWTs and all sorts of fun combining with strong moisture profiling to deliver widespread heavy rainfall. Remains to be seen.

Next few days are just going to be plain nasty for those working outside.

Storms should stay inland today as flow is too ESE over southern areas still.

[Karl Lijnders]

Latest JMA looks very impressive for rainfall accumulations but how reliable is it?? Hmmmm. Has widespread 50-100mm falls over the week. US does as well.

CMC keeps things north but really looks like it is having a moment and NOGAPS pushes things NW but keeps the E dry.. I don't think so.

Very high moisture now travelling down from NSW. Cloud has thickened dramatically.

[Anthony Violi]

Yeah I think they will still end up at the same result..decent showers or rain next 5 or 6 days, then a big event next week. They still aren't connecting it all but they soon will..tomorrow and Friday look very humid, and some decent totals should accumulate, especially about the ranges.

[Supercellimpact]

Tuesday had massive instability 3200 cape and -8 li's over northern Vic. Long way off but next week looks big, and has for a while now.

[I_Love_Storms]

GFS has been on this for a long time now with little variance...instability prolonged now as well until at least next Wed. Rainfall totals huge but believable in this scenario...

Instability Tuesday 5pm:



Rainfall accumulations next 8 days:

[Meso]

This is just getting ridiculous now, I keep expecting to check it and see an end in sight, but if GFS is to be believed we've got storms across the state for another 7 days, with some massive days amongst it all. Are we living Oklahoma now or something?

[Meso]

Hi Meso. There is no such thing as a silly question.

What we have is a trough (the same trough that caused the weekend rainfall) currently sitting roughly right up through central Queensland, extending south over New South Wales and into central Victoria at the moment. Near or attached to this trough is an upper low pressure system, to Victoria's northwest. These are causing east to northeast winds (fairly obvious) which as a result is increasing the moisture profile across Victoria and the eastern states. Due to the trough and upper low, steering is actually out of the northeast or east, so general flow of showers/storms/rain has been towards the southwest or west, as seen tonight. It is the upper wind profile which is resulting in the rainfall coming out of the northeast. Does this explain things for you ?

Hmm, it does kind of, Jake. And thanks for taking the time to reply. I'm just struggling to wrap my head around why it doesn't happen very often. I guess I've just gotten so used to the typical pattern of lows coming up through the bight and clipping us before drifting off out to sea.

Is the low eventually going to tilt right back around and put everything back in a westerly pattern? Kinda looks like that is whats happening on the satelite with the trough starting to drift off the east coast, but I'm probably way off!

[Karl Lijnders]

Upper low is driving the storm focus and that shifts SSE over the coming days. We will stay in a NE flow until next week with the block continuing in the region.

[Jake Smethurst]

That's alright Meso, just trying to help you out here.

We see this type of pattern more frequently in Summer, however I cannot remember one time where US has been progging this much instability for so long in its model runs. Very rare. Shower/storm motion should by Saturday start to move towards the southeast again as usual, upper profile changes, so instead of things coming in from the northeast, they will come in from the northwest again. Unless models change again that is. Surface flow will be NE though into next week.

[Harley34]

Storms look to be EPIC on Monday/Tuesday..

Different sort of situation, with a Low in the Bight moving into VIC.

[Pengaz]

Hi Meso. There is no such thing as a silly question.

What we have is a trough (the same trough that caused the weekend rainfall) currently sitting roughly right up through central Queensland, extending south over New South Wales and into central Victoria at the moment. Near or attached to this trough is an upper low pressure system, to Victoria's northwest. These are causing east to northeast winds (fairly obvious) which as a result is increasing the moisture profile across Victoria and the eastern states. Due to the trough and upper low, steering is actually out of the northeast or east, so general flow of showers/storms/rain has been towards the southwest or west, as seen tonight. It is the upper wind profile which is resulting in the rainfall coming out of the northeast. Does this explain things for you ?

Hmm, it does kind of, Jake. And thanks for taking the time to reply. I'm just struggling to wrap my head around why it doesn't happen very often. I guess I've just gotten so used to the typical pattern of lows coming up through the bight and clipping us before drifting off out to sea.

Is the low eventually going to tilt right back around and put everything back in a westerly pattern? Kinda looks like that is whats happening on the satelite with the trough starting to drift off the east coast, but I'm probably way off!

Also worth mentioning Meso that this scenario often occurs when there is a strong to very strong High Pressure System in the Tasman Sea/NZ. This creates a blocking pattern for typical west-east weather pattern movements that we are used to (i.e. lows and cold fronts are not strong enough to penetrate through). Rather, we tend to see a more stagnant weather pattern develop, with North Easterly winds on the west side of the strong high pressure system influencing our weather through directing tropical moisture further south than usual (often hear the term "fetch" used to describe this). This results in the Low pressure trough and upper low extending into Victoria (and the associated sporadic shower and thunderstorm activity- as is the case at the moment).

We're normally used to the trough located further north over NSW and QLD (as in a typical Late Spring to Early Summer pattern)- in December 2004 a similar weather pattern lasted for a week here and delivered good rains to most of Victoria.