Predictions 22nd - 26th June System

Vermillion

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Majikthise

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I am used to the models dipping and dampening expectations but I like to see this a bit further out
..reckon @PlowKing was on the money
.range should be 25-27th and follow up 30->
 
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janesweather

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My explanation this morning:

Tropical moisture from the Indian Ocean surges down and meets up with a strong front. This should form the trifecta of moisture, instability and cold air, perfect for snow. A centre of low pressure should form and become cut off from the westerly airflow (that wants to move our weather systems through quickly). This is even better for snow, as its slow-moving and can deliver snow for longer.

The slow movement does mean there is time for the atmosphere to warm up a bit, on Monday and Tuesday (but not like we’ve seen recently). This system will be carrying plenty of cold air and plenty of moisture, so the initial rain will quickly change to snow. I’d expect rain to develop late Tuesday, and turn to HEAVY SNOW during Wednesday. Then, front after front should be able to move through, and deliver EVEN MORE SNOW. This has the potential to add up to a big snowfall next week (more than 50cm), but most of it above 1600 metres.
 

The Plowking

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My explanation this morning:

Tropical moisture from the Indian Ocean surges down and meets up with a strong front. This should form the trifecta of moisture, instability and cold air, perfect for snow. A centre of low pressure should form and become cut off from the westerly airflow (that wants to move our weather systems through quickly). This is even better for snow, as its slow-moving and can deliver snow for longer.

The slow movement does mean there is time for the atmosphere to warm up a bit, on Monday and Tuesday (but not like we’ve seen recently). This system will be carrying plenty of cold air and plenty of moisture, so the initial rain will quickly change to snow. I’d expect rain to develop late Tuesday, and turn to HEAVY SNOW during Wednesday. Then, front after front should be able to move through, and deliver EVEN MORE SNOW. This has the potential to add up to a big snowfall next week (more than 50cm), but most of it above 1600 metres.
Just potential imo.
 
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Gerg

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I guess we need a primer Verm. Why is tropopause adiabatic 1000 hPa temperature (very roughly tropopause height) a good measure to look at? Any special things we should look for, beyond the general "LWT" shape? Sure does makes a nice plot...

(Did you study with Hakim?)
 

Claude Cat

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mean_sea_level_pressure_and_24h_cumulated_precipitations!120!Australia!msl!pop!od!oper!w_mslrain!2015061812!!chart.gif

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IMO the system is not nearly as cold (as we said yesterday), yet there's plenty of moisture.
Nothing much on the 22nd but slowly building Thursday and Friday. Temps will be marginal but good above 1600m. There a hint of a wandering cold pool on GFS which might help 500 hPas of -25 would see a lower now level.
 
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Vermillion

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I guess we need a primer Verm. Why is tropopause adiabatic 1000 hPa temperature (very roughly tropopause height) a good measure to look at? Any special things we should look for, beyond the general "LWT" shape? Sure does makes a nice plot...

(Did you study with Hakim?)

Sorry, as it's an observation I should have put it in the Obs thread. I am looking at the cutoff low over us (there used to be 2), and also looking at what's coming. Here's a quick list of tips for these charts:
1) Look for the blueish bits. A front will be along the eastern boundary of it.
2) If there is a decent gradient between the red and blue along the eastern boundary, expect a rainband.
3) Development always occurs to the east of the blue. So in our case, the lows are developing to the east of these two cut-offs.
4) The darker the blue, the colder the air and more energy in the system.
5) If the blue is on its own and surrounded by less blue to yellow or red, this is a cut-off and expect development to its east. It may take a few days to a week but it will happen.
6) If you havea big region of yellow or red, its a high. In this case, see how the green is cutting to the south of the blue over us. This is why the cold air is "cut-off"
7) The boundary between the dark red and yellow/green/blue is the axis of the sub-tropical jet stream.

No, I didnt study with Hakim.
 
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Vermillion

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Nov 13, 2005
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mean_sea_level_pressure_and_24h_cumulated_precipitations!120!Australia!msl!pop!od!oper!w_mslrain!2015061812!!chart.gif

get_legacy_plot-web249-21afb3424b395e92cb7f1b5bc9f473fd-FFxCBF.gif


get_legacy_plot-web248-21afb3424b395e92cb7f1b5bc9f473fd-MjXyTa.gif


get_legacy_plot-web249-21afb3424b395e92cb7f1b5bc9f473fd-jhGKh6.gif


IMO the system is not nearly as cold (as we said yesterday), yet there's plenty of moisture.
Nothing much on the 22nd but slowly building Thursday and Friday. Temps will be marginal but good above 1600m. There a hint of a wandering cold pool on GFS which might help 500 hPas of -25 would see a lower now level.

Might be suitable for NSW, but this isnt going to start the season at Buller and VIC based on the current charts. But remember it was just a couple of days ago some people were talking 700-800m snow level for these systems...
 

Claude Cat

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Might be suitable for NSW, but this isnt going to start the season at Buller and VIC based on the current charts. But remember it was just a couple of days ago some people were talking 700-800m snow level for these systems...

I don't think it will open up much in Victoria IMO. At best it will consolidate the man made areas, perhaps open a few more of those up.

The best chance is that the cold pool marries up with the moisture and we could see snow down to lower levels.

15062500_1812.gif


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but with nearly a week to run, anything can happen and predicting those cold pool movements is tricky.
 

7wombathead

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My vibe at the moment is that system is jinxed by a low forming in the south western pacific that will slow it down and it will get marginal as already GFS is suggesting. But whats behind it will deliver winter. Looks like embedded fronts and lots of cold air. I was just hoping for a base before it arrived.

Check it out.
IDY20001.T-500hPa.144.png
 

Donza

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As @Claude Cat has said .
GFS offers quite a nice scenario for NSW.
Moves a broad cold pool through Tuesday night @500 and with nice winds at 300
You can see via the spag that its very upper level and cutoff.
Me thinks people are looking at the thickness thin blue line a wee bit too much.
 
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Donza

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Fairly broad area of decent tot tots as well. Value of 55's with a nice hook at 300 over Victoria @144 hrs via GFS.
 
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Donza

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To get tot tots of 55 or so something has to be cooking in the upper atmosphere , thats for sure.
Hence why GFS has progged so much moisture .
 

Snorkler

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My explanation this morning:

Tropical moisture from the Indian Ocean surges down and meets up with a strong front. This should form the trifecta of moisture, instability and cold air, perfect for snow. A centre of low pressure should form and become cut off from the westerly airflow (that wants to move our weather systems through quickly). This is even better for snow, as its slow-moving and can deliver snow for longer.

The slow movement does mean there is time for the atmosphere to warm up a bit, on Monday and Tuesday (but not like we’ve seen recently). This system will be carrying plenty of cold air and plenty of moisture, so the initial rain will quickly change to snow. I’d expect rain to develop late Tuesday, and turn to HEAVY SNOW during Wednesday. Then, front after front should be able to move through, and deliver EVEN MORE SNOW. This has the potential to add up to a big snowfall next week (more than 50cm), but most of it above 1600 metres.

I like how it's so digestible
 
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7wombathead

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Observe how Low in South West Pacific wedges High and stalls the Cut off low and cold pool slips south of Alps. Then the next deep polar low 930 rises north and bang.

Me thinks the date range needs to extended out to the next system to cover the dominant Polar low.

IDY20001.mslp-precip.132.png
 
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Karicta

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It's all about the race between the ridging high and the cold front in the 24 hours after the above prognosis. I fear the ridge will win.
 

Donza

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What I've done is compare the runs of both axs-r and gfs.
Both are way colder and less cutoff.
AXS- R doesn't elongate the high near perth. Hence the low doesn't get as cutoff.
 

Donza

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Point in case
EC vs AXS-R
huge huge divergence
temps- EC is cutoff, AX-R is not
shape- elongation
pressure. Check EC's central pressure and contrast to AXS-R
IMO folks , beyond 72 hours is a lottery , when progression is being talked about.
This is on the upswing
10445523_10153025528038178_5033798960587910129_n.jpg


11125266_10153025448093178_7032652183990402925_n.jpg
 

Astro66

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Access G shows the Low Pressure starting at about 994 millibars. But the time it crosses into VIC its dropped right off to 1004 millibars.

output_S20gCy.gif


GFS shows pretty much the same.

output_nSPJdC.gif
 

Astro66

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And with the death of the low. The cold air being drawn in quite clearly when the low is lowest, doesn't hook around and we end up with this cold pool lagging behind.

output_62OM5W.gif
 

Donza

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And with the death of the low. The cold air being drawn in quite clearly when the low is lowest, doesn't hook around and we end up with this cold pool lagging behind.

output_62OM5W.gif
850hpa charts don't really show Cold pools
Just sayin
cold pools are shown on 500hpa charts
 

Donza

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In conclusion. I'm concerned about the cold pool arriving too late, just as it did this week.
No, next week has no correlation (in any way) to what happened last week.
posting 850hpa charts as evidence of something that may occur is a folly .
 
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Astro66

Still looking for a park in Thredbo
Jul 27, 2009
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So I've synced up the Moisture Vs 850's.

Then I've roughly highlighted the Cold Air at Resort levels, in Blue, and Moisture in Purple, to make it more obvious.

Moisture appears to be dried up before cold air arrives.

I'm hoping this better highlights my concerns.

C'mon astro it's a totally different set up
Toatally agree they are different systems. I'm only worried that the Cold Air and Moisture don't sync. :)


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I am Fallen

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Sorry all, I left my password at work so have had to set up a temporary account but as the name says, I am the Fallen. Hope this is OK CC?

I am liking the look of this one and the follow up for a couple of reasons. First one is a shout out to Falls Expat who has been providing some awesome info on the Nino setup which if anyone was following last year, Falls called Snowmagedon a few weeks out from memory. Sorry if I misquote you Falls but a few weeks before the big July dumps (sorry Donz) you mentioned that MJO was moving into its 4/5 region which would lead to a weakening of the Sub Tropical Highs and allow the fronts to penetrate north. And we ended up with over a meter about 2 weeks later.

Falls has just called another weakening of the highs over the next few weeks so it is a good sign. See the El Nino Thread for more info.

Add in the Long Wave showing a good period over the next week and strengthening Polar Lows under Africa.

Back onto my area, there is a warm pool that has established itself under the SW corner of WA sitting at about 19c. The remainder of the bight is still at 12 to 13c so enough of a difference to influence passing systems.

Going by the Models, the incoming low looks to Intensify over this warm pool during Sunday before following the coastline across to Vic by Tuesday Night/Wed Morning.

This is an interesting one to watch as the low will build over the warm pool and pickup a pile of moisture but then needs to travel over cooler water as it heads across the bight which I am hoping will mean it does not warm up too much before it makes its way toward Melbourne.

This is a prime example of what the warm pools do when they are under SA or Western Vic but because this one is peaking under WA, there is a fair distance to cover before it hits the Alps but in this instance, I think the cooler than average Temps in the Central Bight are going to work in our favour and keep this one cold enough to deliver over 1600. I am fairly confident IMO that it is game on for Perisher above 1800 but fingers crossed it delivers for Vic down to 1600.
 
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