VIC: Rain/showers & thunderstorms - October 12th- 14th

[typhoon29]

great the weather is looking interesting while I am up on the Gold Coast, typical! Leave tomorrow get back Friday and the temps here will be between 5 and 10 degs, lovely! Next Saturday 11! Great cricket weather, buuuurrrrrr! Got to love spring 20 odd one day 10 the next!

[droughtbreaker]

EC (on the Norwegian site) actually forecasting 'snow' now for the higher parts of Mount Macedon for Friday night.

http://www.yr.no/place/Australia/Victor ... _long.html" onclick="window.open(this.href);return false;"

This upcoming period of weather has it all basically. You have the warm, very moist air, a slow moving trough forming a low as a front and LWT joins in and very cold air interacts with the warm and humid air, and then a major cold outbreak with potential low level snow.

This is one of the reasons October is probably my favourite weather month. Particularly though, when we have a pumping La Nina doing its work.

[Blackee]

Sorry Ryan but Saturday is looking putrid for Cricket.
Listened to Terry Ryan (BOM) after the 11am news this morning and he was suggesting only 14c for Saturday with low level snow.
Wasn't overly bullish regarding the mid week event, but given the complexity, best to hold fire until this time tomorrow.

Was up at Numurkah overnight and the place is looking brilliant. Still lots of water lying in paddocks whilst the high water marks were easily identifiable at Nine Mile Creek, Broken Creek etc. Goulburn had dropped quite alot, but the channels were choc-a-block.

Back to the current topic, EC gives us 70mm from Tuesday til Sunday. Will be happy with half of that!

[johnno]

Heaps of convection today to the NE, N , NW and Western sky alot more than I thought there would be which really sets up nicely for the following few days

[Twister]

This is looking a VERY interesting week, but looks like here in the NW we may miss out on most of the big action.
As cold outbreaks do little up here. and the trough looks to really ramp up JUST east of here, so might be lucky to get 10mm for the week which would suck, be happy with 20mm for the week though.

Central and East areas looking quite good at this stage, NE areas looking really good for 50-100mm for the week, the mounts may see over 100mm which would be just unreal.

Trough wanders through Tuesday with storms looking good in the West, then rain and storms state wide Wednesday clearing far west Then it could do anything.

If cold pool and upper trough move up over SA then a Low will form Over E SA, W VIc that would be great for most of the state as many would get huge falls and then wrap around as low move E SE. This was looking Good on EC and Ac last night.

Today most models have the cold air moving up over W Vic this would cause more of a cold outbreak across the state and develop the low E Of Tassie so only gippy and coast and E burbs would do well out of this.

EC had an unreal Low over E SA yesterday, sadly now its Cold outbreak like most other models, but its early days and models will be all over the place till about Tuesday avro i think, then we will have a better idea of what to expect

SA Bom going for 20-40mm with that trough Mid week so if the troughs continues to develop then the low later in the week, NE and mount regions could see over 100mm for the week which you would think would cause more flooding.

Another week in were will be watching the models like a hawk, and hopefully this is the start of another 6 week long wet cycle

25c with light E NE wind atm, and not a cloud in the sky PREFECT.

Bring on a HUGE week of rain and storms for EVERYONE

[Harley34]

Well, what was a sunny day, has now turned rather cloudy (lines of small CU), and a little breezy. Good to see that the instability has already risen a notch from yesterday.

IMO, storms will be pretty decent this week, especially on Tuesday afternoon/Wednesday, although to get the best idea probably better off waiting until later tomorrow. Not really looking forward to this unseasonal cold outbreak they have forecast, although it could flare up a few storms here's hoping. I was rather hoping this transitional period would be quicker, although it still is October. I remember it being a couple of years ago, the middle of October and one day was 35, the next only 14, so anything can happen.

[stratospear]

I'm not overly optimistic about big rainfall totals here (north of divide) this week, although Tuesday's trough could surprise. It's interesting watching the MJO pulse which is super-strong in phase 5 atm. This is often a precursor to a burst of wet weather.
http://cawcr.gov.au/bmrc/clfor/cfstaff/ ... 0days.html" onclick="window.open(this.href);return false;" onclick="window.open(this.href);return false;

[droughtbreaker]

This is going to be more a rain event than storms IMHO. Sure there will be some decent storms around, mainly in the western half of the state, but the models seem to be downgrading. I am no expert though and there is a lot more to it than just LIs and CAPE so I'll leave the authoritative analysis to those in the know. Either way, the storms that do form have the potential to deliver flash flooding and rain areas will be heavy.

If anything the cold outbreak is ramping up even more for Friday night into Saturday but I am just looking at latest GFS for that. Some -6C 850T now apparent in the progs for parts of the NE of the state. Also very interested in the -1 to -2 LIs with the cold burst Friday night. Upper levels are progged very cold and there will be some serious instability with a big outbreak of cold air Cb. It could get very interesting, particularly for eastern Melbourne through to the Yarra Ranges, South Gippsland and Mount Baw Baw.

Thundersnow anyone?

[Karl Lijnders]

Will be stronger storms than last week come Tues and moreso Wednesday after the rain breaks.

Can't take any of the LIs or Cape values seriously at this time but as a guide.

Models had nothing here Wednesday last week and I had 30mm in 30mins.

North VIC will get 50-80mm IMO.

No problems that I can see and I fear that a slight wobble I can see in prognostics are being interpreted as a downgrade which is not the case.

[Supercellimpact]

Hope this system does it for some decent storms here in bendigo.

[Twister]

Yeah E of Swan hill should see big falls 40-60mm with up to and over 80-100mm in the NE as rain and storms feed into NE Vic from the N NW as trough just hangs through Central NSW and into N, NE Vic.
Hoping trough can stall just a little further west through W NSW and into W and Central Vic then everyone would get big falls.

Looking more cold out break, than big cut off low late week, but first have this almost stationary trough to get through which will dump widespread impressive falls and some nice storms about to
Wish it was Tuesday morning lol

Was 28c today with light NE winds, just great

BTW as mentioned it is looking quite cold on Friday and Saturday, with temps in the low teens and would guess snow to about 800m maybe lower, will be a big shock for people enjoying the warmth next few days

Might see up to 30cm of snow which would be pretty impressive but not rare

[droughtbreaker]

Will be stronger storms than last week come Tues and moreso Wednesday after the rain breaks.

Can't take any of the LIs or Cape values seriously at this time but as a guide.

Models had nothing here Wednesday last week and I had 30mm in 30mins.

North VIC will get 50-80mm IMO.

No problems that I can see and I fear that a slight wobble I can see in prognostics are being interpreted as a downgrade which is not the case.

It's not the rainfall that is downgrading, it's the storm potential. There is a chance that thick cloud and rain areas could impede thunderstorm development, this happens a lot in summer when we have a hot and very humid air mass with instability, in this scenario with warm air and very high humidity you would expect rain areas to develop pretty rapidly.

[Ken]

The numbers currently being suggested by EC (re the cold air) are pretty amazing for this time of year. Its scenario calls for sub-zero 850hpa temps to start pushing up over southwest WA from Thur morning before surging up over a big chunk of SA followed by most of VIC, southwest NSW and southeast SA. Then comes the sub -3C 850T's surging up over VIC/southern NSW by Sat morning with pockets of sub -4C before shearing off as a cold pool that continues moving NE across the rest of VIC and southern/central NSW while most of SE Oz is left under sub-zero 850T's til later in the weekend.

EC's forecast 1000-500mb thickness values are also remarkable with values down below 532 dm reaching southeast SA/western VIC by Fri morning and sub 528 dm values over central VIC before shearing off and continuing NE'wards.

The above-mentioned forecast values are cold enough to satisfy the thresholds for most of the past snowfall events on Melbourne's nearby hills while they fall a bit short of snow down to sea level or in Melbourne itself. That's of course, if this scenario pans out exactly as expected. The cold air surging up over SE Oz is a realistic prospect but just how cold and exactly where, is still up in the air (EC's uncertainty maps still show a fair bit of uncertainty around the coldest air which is typical of systems that have, or are about to cut off). OCF as well as EC currently suggest a max of only 12C for Melbourne Airport on Fri. The front ahead of it is progged to stand up impressively so with the instability ahead of it, it will be interesting to watch. Meanwhile, below is one of the progged snowfall forecasts for the next 4-6 days:

[johnno]

If I'm reading things right EC tonight has snow down to 400 metres Ken Friday night/Saturday morning?

[droughtbreaker]

It is probably the main interest with this system now. Not because we are not going to see heavy rain and storms around through this week, we will, but this progged cold outbreak would be highly significant in historical terms if it came off.

It probably won't be quite as amazing as the October 1995 system was.

Broken Hill had maximums of 35.2C, 11.8C and 6C on consecutive days from the 19th to 21st October that year. It is a solid reminder that our weather 'used to be like this'.

[droughtbreaker]

If I'm reading things right EC tonight has snow down to 400 metres Ken Friday night/Saturday morning?

I know that GFS is definitely saying 600m at this stage but quite easily could be as low as 400m. Not sure about EC though, I'll let Ken answer the question.

[Ken]

I would think it's a possibility johnno but as most here know, it really depends on whether the air will be as cold as suggested and in the right area. Given it's still early days and the level of uncertainty atm, I don't think it's something to bet money on yet. To give you an idea, EC ensemble is currently painting a small area of up to 15% probability of snowfall around the higher parts of the Grampians by Fri night (around 30 to 50% in the Alpine areas). By Sat night, the Alpine areas are showing up to around 60% with lower probabilies extending further SE over lower terrain. There's some very low probabilities ( <5%) being smeared over some lower areas surrounding Melbourne and to the west but this might be more due to the uncertainty from extreme outliers in this model. So given the spread being indicated, a future downgrade/upgrade in the forecasts from this model isn't out of the question yet.

Btw the snow forecast map in my previous post is from snow-forecast.com (which I believe still uses GFS data).

[Twister]

BTW another interesting note is the HUGE rain band forming on the edge of this cold air through NT, QLD, and NSW easy 50-80mm band through much of these states looks very wet again for N NSW and much of QLD and NT.

Cold air is looking quite impressive snow to 400m would be quite impressive this time of year.
Also the CAA (cold air advection) proged on models over SA is intense, gale force S winds across much of SA and into W Vic later, temps will drop quickly behind this front late Thursday into Friday

With such impressive CAA and WAA would expect a strong and deep low to form over SE NSW, E, NE VIC, and quickly move SE bombing in the Tasmen

Still looking like we will be dry slotted up here in NW Vic, and parts of E SA and far SW NSW, hoping trough can deliver locally.

Once again east of a line Swan hill to Melbourne looking to get big falls once again which is typical La Nina wheres its effects are less in far W Vic than Central and E Vic
Though cold burst will bring good falls to SW Vic with onshore flow.

Lots of weather to come very active week looking forward to it.

[Rhino]

Fri/Sat looking really interesting not just for cold air and snow but big falls probable. EC has always had soild falls around Fri but seems to be a big upgrade tonight, although the details will change somewhat over the coming runs. Has around 70mm for my area locally Fri-Sat and I really never gave that system much of a thought as I thought the systems earlier in the week would be more productive, now I have no idea what to think, certainly not going to complain though. This week will be a good one,warm temps to start it off, heavy rain, storms, snow and bloody cold temps to top it off.

Rhino.

[Karl Lijnders]

I think the cold pool will ease somewhat in upcoming prognostics, and this will see higher rainfall return to higher ranges etc.

I suspect still substantial storm activity developing over the west Tuesday, spreading to C areas overnight into Wednesday. ACCESS potentially has 60mm in some areas of Central areas on the first band if the best case scenario unfolds.

I do think the weekend will hold another 50-70mm over this area if it is just a cold blast with showery cyclonic SW winds.