Vic: Long warm/hot spell, unsettled end - December 24-31 2016

[hillybilly]

Progs showing a long warm to hot spell starting around December 24. We have a monsoonal low or TC to our northwest and a upper low over Queensland which set up a blocking pattern over the southeast. Uppers are hot - mostly in the 15-22C range so away from coastal sea breezes should be mid 30s+

Progs trying to develop the odd thundery shower which might break up the heat.

Fair bit of uncertainty in the details as the track of the low will determine whether we get much tropical moisture of just the heat.

[JasmineStorm]

Thanks for the thread HB
One of Earth's largest and most influential weather systems is coming to say gday again and it's setting up a serious weather scenario for Victoria in this thread. Agree with HB in that it will depend on the position of the tropical low's / cyclone but this morning the big models are starting to whistle the same tune with regards to the path it's taking. Monsoonal related low's are notorious for changing their minds though...... I'm also seeing the high pressure systems dropping a lot further south now meaning the Hadley cell is near 30 latitude! Summer has arrived!!

On current guidance of EC, Access and GFS ....we have an explosive set up involving a very warm build up to possible multiple days over 40's (26th,27th & 28th) with a band of rain and storms to follow. IMO at the moment unless that big low / Cyclone goes out to sea, it looks ominous for extreme to code red days around the 27th and 28th

[jimmyay]

BOM going for 30 degrees on Christmas Day now Might go a couple of degrees higher than that I'd think.

[Harley34]

Some of you might not have noticed, but if you look at the bureau's latest 4-day synoptic chart, it has the highs and lows building a pattern, to where it all connects. The connection looks like dominoes, where each weather system helps to assist in moving the others, but in a beneficial way towards severe weather or rain. If there's a hot day or 2, it'll will be the key to good precipitation and convection. Things are looking exciting. I've been on this forum for 6 years and I'm 24, so to say that I'm keen again has been because of the weather returning to interesting.

Indian Ocean and the Monsoon looks crazy from tomorrow onwards. The amount of lows and the inclination for deepening is awesome. The waters are boiling up north and even a general Australian news website said this, so something is up...

[JasmineStorm]

Some of you might not have noticed, but if you look at the bureau's latest 4-day synoptic chart, it has the highs and lows building a pattern, to where it all connects. The connection looks like dominoes, where each weather system helps to assist in moving the others, but in a beneficial way towards severe weather or rain. If there's a hot day or 2, it'll will be the key to good precipitation and convection. Things are looking exciting. I've been on this forum for 6 years and I'm 24, so to say that I'm keen again has been because of the weather returning to interesting.

Indian Ocean and the Monsoon looks crazy from tomorrow onwards. The amount of lows and the inclination for deepening is awesome. The waters are boiling up north and even a general Australian news website said this, so something is up...

Yes, there is plenty going on with the BoMs 4 day chart. The latest wind map at 700 hPa is starting to show the lows giving a nice rotation with the north westerly monsoon bursts getting them cranking
https://earth.nullschool.net/#current/w ... 091,-9.316

[I_Love_Storms]

Latest GFS is insane for WA and NT, never seen estimated rainfall totals like it so much and so widespread (500-800mm!!) surely Gfs has mucked 06z run up. Btw even though the airmass here looks hot it's also forecast to be pretty humid, so not sure about really bad fire weather fortunately. Precipitable water values are 30mm on 24/25/26 dec! The monsoon is off its chops. Don't be surprised at some gigantic systems including potentially explosive cyclones up north in the very near future. If this GfS 06z run comes off it'll be a catastrophe for inland Australia. I can't imagine 500mm+ falling over a very widespread area over a few days

http://stormcast.com.au/raincast.html?o ... :192:wa#sc

[hillybilly]

Latest progs are nasty. 850Ts into the mid 20s with light winds, mainly off shore. Would be hard for places like Mildura to avoid multiple low/mid 40s. Even Melbourne could see a numbers of 40s. Will come down to cloud, humidity (convection) and if the sea breezes can come in.

Thankfully winds aren't too strong on most days.

[JasmineStorm]

Models are becoming really hostile now.....I love it when the monsoon arrives Bamboozles everyone and every model hours at a time. There is dynamite in every last model run but for different reasons. Currently all have a very warm to hot lead up...then I see the following across Vic.

CMC = Explosive line of storms early Dec 27th followed in by a tropical fed water bomb on Dec 27th 100+mm
GFS = Decent Heat wave from Dec 23rd then a stormy change on Dec 27th. 5 to 15mm
Access = Moderate heat wave with a stormy rain band change Dec 27th. 30 to 60mm
EC = Moderate heat wave then a stormy rain band Dec 27th. 10 to 40mm.

But watch it all change if the monsoonal lows change their minds.....which they normally do! Looking at the latest on the low's, the Indian ocean low is now showing signs of cyclogenesis. Dropped to 1003 hPa, has a small eye and 60 km/h surface winds on the northern flank. 2nd low near Darwin is starting to deepen slowly at 1004 hPa. Some models have them merging in the next 2 days. https://earth.nullschool.net/#current/w ... 26,-15.429

GFS changes it mind on the southerly affecting coastal victoria every run but the last run looks hot for some southern areas at chrissy. BoM's forecast will be interesting later.

[JasmineStorm]

http://www.bom.gov.au/cyclone/index.shtml

As I suspected from this morning.....it started to deepen quicker than models forecast. 996 hPa now

[I_Love_Storms]

At least one 40 day looks likely maybe a spike day up to 42 or so is even possible if latest GfS is to be believed with high wind as well, but still a rather moist airmass for that level of heat. Let's see where this cyclone goes. It could be the difference between nothing and 100mm

[Jake Smethurst]

Good pick up Jasmine re the low deepening.

Models very much agreeing on this heat now, it will just come down to whether or not coastal regions, including bayside Melbourne, can escape the worst with any seabreezes. My two cents worth, I think the northerlies will keep on top of any seabrezes during the majority of the days. I suspect the BoM will adjust their maximums a little closer upwards.

The biggest question now is, can we hook into that moisture from the tropical cyclone and pick up a nice system for ourselves? Most models tend to agree on some sort of moisture capture as Jasmine beautifully pointed out above, but to what extent is yet to be seen. Definitely looks like storms will play a role on whatever change moves through next week.

Also could be quite windy ahead of whatever system takes form, that's another variable the models are indicating, which means a couple of bad fire weather days likely. Fortunately, the state is not as dry as what it could be at the moment.

[hillybilly]

Progs are messy, but seem to be consolidating a bit. We've basically got a weak trough near central Vic Fri/Sat/Sun which moves through for Boxing Day, before we go back into northerlies for a day or so before a rainy front. Most day don't have much wind, and the flow will vary form northeast to southeat (though Chrismas Day and around the 27th look more northerly).

North of the divide is basically just hot starting Thursday. 850Ts will support a series of 40s

Progs pretty keen on the odd shower and storm for central areas Fri, Sat, Sun and Monday. Not a lot in it (except about the northeast and far east) but a bit.

Hottest days in the south look like being the 25th and 27th.

Of course, could all change with the next set of runs. The critical thing for us is if the tropical lows come across north of the ridge (good for rain/storms) or south of the ridge (bad).

[JasmineStorm]

Well….. what a thread this has potential to be. At the moment, I think anything beyond Dec 26th is a guessing game for every human and model. Volatile swings with the models every time they run. Yesterday’s BoM 4 day map was out of date as soon as it was published with the rapid intensification of the Indian Ocean low….. EC had an upgrade and downgrade for Vic in 24 hours that had to be seen to be believed.

Here’s what I currently see
Indian ocean low is currently located over surface water that was measured at UTC 12pm yesterday to be 30 to 31 degrees and is starting to look organised. NT low is slowly deepening at 1001 hPa but is less organised at this moment.

https://earth.nullschool.net/#current/w ... 33,-12.480

What these 2 monsoonal lows do beyond Dec 22nd is up in the air so every scenario after Dec 26th for Victoria is up for debate. Here are my favourite snap shots from today’s models (The access Dec 28th run made me check the gutters for gum leaves and twigs)

Image 1 – The Access oven. Dec 28th 5pm at 850 hPa.
Image 2 – The CMC nuclear storm front. Dec 28th with a follow up Dec 29th mid latitude cat 1 cyclone.

[Horts]

Really looking forward to all this, look at that heat!

heat.JPG (150.4 KiB) Viewed 11077 times

[jimmyay]

Bom now going for 35 Xmas Day
Can't see the cooler Boxing Day temp of 32 myself, think that may also upgrade.

[hillybilly]

Model jumps continue. EC now has the second low coming over the top of the approaching high passing close to Vic with a linger trough. The scenario would bring down alot of tropical moisture. GFS is very different with the low passing into the westerlies to our west and largely missing us.

Hope EC's correct

[Macedonian]

Sounds like a christmas from hell to me.
yuk.

[JasmineStorm]

low near Darwin is showing strong signs of cyclogenesis....pressure dropping below 998 hPa , 60 km/h on the northern flank and her core is now over boiling water with heaps of convection.

https://earth.nullschool.net/#current/w ... 80,-13.639

According to the big boys at JTWC the Indian Ocean low is already a cyclone..... BoM have a different threshold.
https://metoc.ndbc.noaa.gov/ProductFeed ... sh0217.gif

This is one crazy set up currently underway. 2 cyclones a real chance IMO .....for at least a short period

[hillybilly]

Progs just keep evolving. Christmas Eve now looks like being a bit thundery. Boxing Day front is much stronger and should have a rain or shower band.

Also watch for convective showers on the 23rd - ACCESS, CMC and GFS all have showers around.

Quite a split between the models from the 27th EC quicker. GFS and ACCESS slower. The one day that looks very hot across all models is the 28th. Is going to be hard for Melbourne to stay below 40C that day

[JasmineStorm]

I'm keeping a close eye on these lows..... as they are changing the model scenario's almost hourly at the moment. The Indian ocean low is having a real struggle with shear which is why its not a cyclone yet and it's moving real slow. I think the last model runs don't factor that in as much.....I can see why the BoM have very short outlook cyclone tracking maps

http://tropic.ssec.wisc.edu/real-time/s ... 000&loop=0