Predictions 21-25th June Opening Weekend Cut Off Low

Vandans

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BOM now going from rain Saturday up to 40mm at Perisher!!!
 

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Fast Eddie

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BOM now going from rain Saturday up to 40mm at Perisher!!!
Or snow ;)
A8FF89DF-B93A-4D2E-922D-CE333FAB680A.png
 
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Mister Tee on XC Skis

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The modelling / forecast from Ms. Bunn is ping ponging between "just go surfing" and "wax those skis boyo!".
NEXT 7 DAYS

Mt Buller: 5cm
Mt Hotham: 1cm
Falls Creek: 2cm
Mt Baw Baw: 3cm
Perisher: 4cm
Thredbo : 6cm
Charlotte Pass: 10cm
Selwyn: 2cm
Lake Mountain: 1cm
Mt Stirling: 4cm
Ben Lomond: 2cm
Mt Mawson: 4cm

The BOM forecast for Mt. Hotham now looks a little better.
Sun protection not recommended, UV Index predicted to reach 2 [Low]

Saturday 20 June
Summary
snow.png

Min 2
Max 3
Snow. Wind easing.
Possible rainfall: 25 to 40 mm
Chance of any rain: 100%
rain_100.gif

Cloudy. Very high (near 100%) chance of snow, most likely in the morning and afternoon. The chance of a thunderstorm in the afternoon and evening. Winds northerly 35 to 45 km/h tending northwesterly 30 to 40 km/h during the morning then decreasing to 20 to 30 km/h during the day.

Sun protection not recommended, UV Index predicted to reach 2 [Low]

Sunday 21 June
Summary
snow.png

Min -1
Max 1
Snow showers.
Possible rainfall: 2 to 4 mm
Chance of any rain: 90%
rain_90.gif

Cloudy. Very high (90%) chance of snow showers. Winds northwesterly 15 to 20 km/h becoming light during the morning.

Monday 22 June
Summary
snow.png

Min -3
Max 2
Snow shower or two.
Possible rainfall: 1 to 4 mm
Chance of any rain: 70%
rain_70.gif

Cloudy. Patchy morning fog. High (70%) chance of snow showers, most likely later in the day. Light winds becoming south to southwesterly 20 to 30 km/h during the day.

Tuesday 23 June
Summary
snow.png

Min -2
Max 4
Showers or snow. Windy.
Possible rainfall: 2 to 6 mm
Chance of any rain: 80%
rain_80.gif

Cloudy. High (80%) chance of showers or snow. Winds southwesterly 25 to 30 km/h tending southerly 35 to 50 km/h during the morning.

[Moderators Edit: There's no need to use bold text we can see your post]
 

Jellybeans

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I think it's far from a fizzed.
Just damp at the start and end.
However the duration of the cold pool cutoff is extraordinary.
The cold low is no fizz. It’s going to be pretty epic.
As for the snowfall, jury isn’t gonna be here until Sunday.

5-10cm for the Main Range on EC 00z:
3EECEECF-AB99-4824-8889-BAC86AD8FC0D.png


And then 50cm on GFS 00z:
A3EEB2F8-CA5C-42B8-B48B-A9DF0D424FC1.png


So the reality is there are more questions, than answers right now.
This is one of those systems that is very hard to call, because it is based upon mesoscale changes in conditions.
 

Ken Kato

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upload_2020-6-17_19-38-23.png


upload_2020-6-17_19-38-31.png


Latest suggestions above from one of the ensembles (GEFS) re what percentages of its members are going for what snow depths on the ground (not snowfall accumulations). Well kind of latest – the map uses the 18z run. I'm personally not a fan of the 00z runs because I find them erratic despite the fact they're slightly newer.

Worth noting though that this ensemble is a bit GFS'ish since it's its ensemble and GFS has traditionally had a knack of undercooking snow depths. Remains to be seen whether it's going to be the case this time around too. Also has lower resolution than the EC ensemble so it can miss the smaller scale deeper snow depths due to topography. So would take these with half a grain of salt at the moment.
 

Jellybeans

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upload_2020-6-17_19-38-23.png


upload_2020-6-17_19-38-31.png


Latest suggestions above from one of the ensembles (GEFS) re what percentages of its members are going for what snow depths on the ground (not snowfall accumulations). Well kind of latest – the map uses the 18z run. I'm personally not a fan of the 00z runs because I find them erratic despite the fact they're slightly newer.

Worth noting though that this ensemble is a bit GFS'ish since it's its ensemble and GFS has traditionally had a knack of undercooking snow depths. Remains to be seen whether it's going to be the case this time around too. Also has lower resolution than the EC ensemble so it can miss the smaller scale deeper snow depths due to topography. So would take these with half a grain of salt at the moment.
Yeah IMO Thredbo could get more exciting than that.
 
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POW Hungry

Old n' Crusty
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The big falls progged have the moisture being acquired from the North; not ideal IMO.
once the lows (+ cold pool) move in over Vic and the GDR the tap is turned off.
That is until the low deepens in the Tasman, which again isn't ideal:
 

Jellybeans

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EC - The Deep layer Shear affects are still avoiding the Alps too much. Im always wary of flow patterns like this one. Warm advection in the mix may hamper the outcome. Not blow your hair back kinda stuff imo. Hope im wrong.
QED, hence why EC isn’t showing the exciting stuff.
You gotta have a bit easterly beat all the odds magic here for this to work.
 
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Astro66

Still looking for a park in Thredbo
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My take. Not a lot of overlap on the 540 and the moisture. Moisture appears to be just about done, when the cold pool rolls in, on the front end.

gfs_mslp_pcpn_frzn_aus_14.png
 
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Jellybeans

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My take. Not a lot of overlap on the 540 and the moisture. Moisture appears to be just about done, when the cold pool rolls in, on the front end.

gfs_mslp_pcpn_frzn_aus_14.png
The backend, that’s where they sell the best tickets. But then again, you might go home disappointed.

GFS 6z has gone from 50cm to just below 30cm.
Still nearly quadruple EC’s totals
EC gonna have to take the heat now.
 

Jellybeans

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Back end doesn't look much better. Especially with the Northely Feed. Looks warm and wet, IMO.

gfs_mslp_pcpn_aus_23.png
It all depends on where that low is, and whether it’s early enough and perfect enough to interplay with the well-noted cold airmass.

Maybe it’s too perfect. But we won’t know until it happens.
 
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Astro66

Still looking for a park in Thredbo
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It all depends on where that low is, and whether it’s early enough and perfect enough to interplay with the well-noted cold airmass.

Maybe it’s too perfect. But we won’t know until it happens.
Yeah ......... maybe ........ It looks like it might be cold enough.

gfs_z500aNorm_aus_24.png
 

POW Hungry

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When it does start winding in the GAB. look @ ascat data if you can. Won't be surprised it will have gusts in the 45-50kt range within its outta wind field.
Substantial neg-zonal 35-40knot wind-field (not incl gusts).
For posterity & verification, EC 00z Sat 4am.
Screen Shot 2020-06-17 at 8.59.22 pm.png


AXS coming in hot a bit earlier Sat morning (EDIT).
Screen Shot 2020-06-17 at 9.05.15 pm.png
 

Ken Kato

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Yeah true. But usually you can get a good pass in the GAB with the whole wind structure.They are a scientific data tool used by all reliable agencies world wide.
Hehe yep I know @stormkite2000 , I was just being sarcastic. Was just a reference to a particularly cursed frustrating time in the Bureau when ASCAT passes kept missing the vital quads of developing TC's just when the data was needed the most. And a lot of the otherwise good data suffered rain contamination. Was like a conspiracy on the part of the satellites.
 

Ken Kato

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Yeah mick, its size and multiple emedded centres belies the likelihood that it's probably not going to be a high end system in terms of geographical extent of heavy snow, heavy rain and damaging winds, although you typically don't expect too much inside complex lows anyway. And of course it'd help if it was further south too. Some areas should still see some action though and given how intensely cold the mids are inside the complex low as well as weaker steering winds aloft, would not be surprised to see a reasonable amount of small hail for some places which manage to get any thunder. I'm still yet to be convinced about this system being too exceptional for the majority at the moment unless there's a good upgrade in the coming days (which isn't impossible but time is running out for one).
 

rowdyflat

A Local
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Jun 21, 2003
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Warm wet system. I would buy that if we were talking tropical lows up north in summer.
Ok cool but relatively warm with lots of northerly moisture feed first which wont have anything to melt ,westerly snow later , which wont be great for Falls IMO but as usual it depends where the centre of the low sits and whether a cold pool settles over NE Vic..
 

Xwing

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Jun 22, 2016
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Yr. No will update at 11.15am
At times they end up quite accurate. When I see such a mix of forecasts and even one site saying 2-5cm on one page but 10-20cm on another page (for the same location), I begin to wonder about the editorial process for sake of consistency and accuracy.
 

Ken Kato

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Latest 3D winds (1st graphic) using 12z GFS data for 4pm Sun to 1am Mon. Can clearly see the almost vertically stacked nature of the low extending up into the upper levels.

The 2nd graphic was using a slightly older run (18z) for 4am to 1pm Mon.

Graphics via Unidata/IDV/UCAR:

50018026107_a12467eb95_b.jpg


50015645723_bc5dc5bd89_b.jpg
 

Ken Kato

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I think you meant a 500mb low extending down to the surface. Not visa versa as with tc lows.Selection_188.png
Assuming you were talking about my post containing the graphics @stormkite2000 , not sure what you're getting at there? I was simply referring to the fact that the low extends up through a decent depth of the atmosphere figuratively speaking, once it's fully developed i.e. it wasn't a reference to whether it originates from the midlevels or the surface then develops downwards or upwards through the atmosphere.
 
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