Event SE Aus Cut Off Low & Severe WX for 7-10th June

POW_hungry

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We're several days out and global models still trying to pin the tail on the donkey for the next week. It is however looking likely that we'll see some severe weather and cold temps from Vic to NSW/ACT & SE QLD, all anomaly relative.

The model spread is huge with GFS bouncing around over the last few days, now EC with a big wobble from the trend on this mornings 12Z run.
Snow is looking a sure bet along the NSW/QLD GDR, with snowfall risk from the Southern Tablelands to the Granite Belt.

NB. Via the Alpine Forum we've been talking about the snow impacts in the alpine region for a good week now, should you wish to discuss this snow event impacting the Australian Alpine region refer & contribute to this thread:

Latest GFS putting the bullseye of cold air on the BMs and CT's:
1622850559997.png
 

POW_hungry

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Latest EC Ensembles guidance puts the low straddling central Vic with a broad-reaching moisture feed from the Tasman.
This puts the bulk of the shear, surface winds and moisture bullseye on Vic. Whilst the Cold air extends meridionally up the GDR.
EC Ensembles Thursday:
Screen Shot 2021-06-05 at 10.01.59 am.png


EC Ensembles then transitions this trough/frontal band through SW Slopes & Riverina of NSW:
Screen Shot 2021-06-05 at 10.09.29 am.png
 

Ken Kato

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Latest (00z) GEFS snowfall probabilities above. Apologies for the seemingly obvious caveats in red - had to dumb it down a bit for social media purposes. Naturally, the position of the broad low and any of the smaller multiple centres embedded inside it and pivoting around will be key to who exactly gets what. Those smaller centres certainly don't help our cause re predictability. Will endeavour to do some snow depth script outputs in the next couple of days as opposed to many of the conventional snowfall products around since the latter typically uses an assumed 10:1 snow to liquid ratio and concentrate on snowFALL rather than the amounts that people see lying on the ground at any given time.
 

POW_hungry

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51226039346_e740984ce5_oa.png

Latest (00z) GEFS snowfall probabilities above. Apologies for the seemingly obvious caveats in red - had to dumb it down a bit for social media purposes. Naturally, the position of the broad low and any of the smaller multiple centres embedded inside it and pivoting around will be key to who exactly gets what. Those smaller centres certainly don't help our cause re predictability. Will endeavour to do some snow depth script outputs in the next couple of days as opposed to many of the conventional snowfall products around since the latter typically uses an assumed 10:1 snow to liquid ratio and concentrate on snowFALL rather than the amounts that people see lying on the ground at any given time.
I am interested to hear your thoughts on moisture availability hitting the NT's but particularly the QLD GDR/Granite Belt @Ken Kato
You guys seem to be realists on the lack of moisture through the region of late.
Does this winter front change anything for you mob?
Wednesday PM looks like the best chance of snow on NT's at this stage.
 
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Ken Kato

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I am interested to hear your thoughts on moisture availability hitting the NT's but particularly the QLD GDR/Granite Belt @Ken Kato
You guys seem to be realists on the lack of moisture through the region of late.
Does this winter front change anything for you mob?
Wednesday PM looks like the best chance of snow on NT's at this stage.
I haven't had a close look yet at that side of things since yesterday to be honest but from what I saw then, the depth of moisture improved a lot in the lower levels in the soundings for around the Granite Belt and NT's compared to some earlier runs. So much so that it was actually saturated all the way up through the DGZ as you can see in this sounding from yesterday for Eukey near Stanthorpe. No wonder then that it was putting the word Snow in the best guess precip type panel in the bottom right.

But I just had a quick and dirty look at the latest GFS soundings for Eukey and they look drier as well as warmer aloft. Not the biggest fan of the currently forecast W to NW component of the low level flow in that area due to the position of the low. But still a lot of wriggle room for that to change in future runs (possibly).

I'll have a closer look at the all important 1000-700 and 1000-850hpa thickness values for the area tomorrow since 1000-850hpa thicknesses close to or below 131dm have correlated well with past snowfalls in that area.
If future runs in say a couple of days time are showing reasonable moisture/cloud depth up through the DGZ with sufficiently cold lowers, I'd probably be ready to say yep, it's a guarantee. More a formality to me though since I've had accom arranged near my fave spot for awhile now so I'll be going there regardless.
 

bas1

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Yes Thursdays freezing levels not good down south
Much better as you go further north
 
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bas1

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Mount trickett freezing levels
 

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Snowmaker7

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WOW. This morning's runs on both GFS and EC look scary. GFS going for near 70cm for the Oberon plateau, 20cms for the SHs, ~50cm for Crookwell/Goulburn and 50-70cm for a large area of the Snowys. EC is not too far off. Possible snow chase to Crookwell on the cards for Wednesday. Although it could be absolute chaos
 

Humphrey

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WOW. This morning's runs on both GFS and EC look scary. GFS going for near 70cm for the Oberon plateau, 20cms for the SHs, ~50cm for Crookwell/Goulburn and 50-70cm for a large area of the Snowys. EC is not too far off. Possible snow chase to Crookwell on the cards for Wednesday. Although it could be absolute chaos
 

Snowmaker7

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Yeah, I am not seeing anything remotely close to that for OP.
That GFS run was a big outlier.

Perhaps 10-20cm for the OP, IMO.
18z is not too dissimilar, but not as much snow for the CTs, and colder air further south. Places like jindabyne, Bombala etc could get hammered. GFS saying 80cm for Jindy. EC obviously looking a little more realistic.

Trajectory of the cold air is vital (and still changing run to run), but I think you can almost certainly lock in an amount of snow in a place that has not been seen for many years
 

POW_hungry

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18z is not too dissimilar, but not as much snow for the CTs, and colder air further south. Places like jindabyne, Bombala etc could get hammered. GFS saying 80cm for Jindy. EC obviously looking a little more realistic.

Trajectory of the cold air is vital (and still changing run to run), but I think you can almost certainly lock in an amount of snow in a place that has not been seen for many years
Yeah, look at the synoptic set-up, the Tasman moisture has to come over the GDR and wrap to hit the CTs.
It's not the set-up for the falls suggested above IMO.

MAYBE 20-30cm for places like Mount Trickett IMO.

However, I agree the ST's above 800m in the firing line Wednesday/Thursday IMO.
 

Ken Kato

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For what it's worth, here's the latest (18z) suggestion from GFS. Should go without saying that this is the max snow depth on the ground achieved during the given period by the model (where the model factors in various snow to liquid ratios and accumulation vs melting/sublimation rates).

It's not a forecast snowfall amount map which is the most common type of snowfall map on websites that typically use an assumed standard 10:1 snow to liquid ratio which varies depending on the type of snow that falls and therefore, isn't necessarily representative of the depth of snow lying on the ground at any given time (also due to the fact that snowfall amounts aren't the same as snow depths due to some melting, etc).
Of course there'll be locally much deeper or shallower depths in some places from what's shown on this map due to topography, model error, etc.
 

bas1

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I’m going to leave sydney around 3 pm
So should be in Oberon 530 ish
This could be a one in 20 year event ❄️❄️❄️
 
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Jellybeans

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Be careful up that way. August last year I did a snow chase to Oberon and there were punters off the road everywhere. Expect Jenolan Caves Rd to close from Hartley
I think they closed all the roads in the Oberon shire at some point during one of the systems.
 
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Humphrey

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I’m going to leave sydney around 3 pm
So should be in Oberon 530 ish
This could be a one in 20 year event ❄️❄️❄️
We will be in Oberon around 1 to 2 pm
Staying overnight and will be in a white high top Troopy .
Say hello if you see us .
Cheers
 
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ecowain

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Be careful up that way. August last year I did a snow chase to Oberon and there were punters off the road everywhere. Expect Jenolan Caves Rd to close from Hartley
Plus the locals got pretty riled up by the bogan snow seeker behaviour last time around. Also, the road south of Hampton has only just reopened to thru traffic. Last thing they want is it to get blocked again... Going to be messy on the roads, I predict.

My wife will be working out in the middle of Kanangra for the whole week, she's taking pretty much the clothing she takes when ski touring.
 

SnowBound

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Maybe I’ll leave a little earlier
Ec is suggesting the bulk of the snow is from after 8 pm Wednesday
You might be alright then. I’ll be in Blackheath from lunchtime Wednesday at my folks place. Fingers crossed we get something. Usually when the OP gets 20cm, Blackheath gets a dusting.
 

almontyrat

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Just had some flooding in my kitchen in NW tassie. Not from below (I live on top of a hill) but raining down inside in volume. I called my landlord (who conveniently lives next door) who held the ladder while I climbed up in torrential rain to unblock the down pipe. We will have a proper look in the morning so I just hope I cleared it well enough not to wake to a reflooded kitchen.
 

Ken Kato

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Understandably, the expected rainfall's another aspect of this system that's been overshadowed by the snow but eastern VIC/southeast NSW still looking like they're in with a shot at pretty decent wetness. Only if the low and the wraparound behaves though.
Also, some GEFS snow stuff for those either side of the QLD/NSW border.

P.S. LOL @ bogan snowseeker behaviour... had plenty of them during the deep big 2015 snowfalls up here as well, trampling fences, wandering onto private property, etc.
 
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