Predictions 9-11April Cut Off Low

[POW Hungry]

Bit early for the talk of cut off lows but it's been progged for a few days now. Both GFS, EC going for a cut off scenario into the Tasman with good upgrades run to run, across moisture and cold air. Alps look to get a good dousing with a real possibility of snow accumulation above 1800m as mentioned yesterday.

Cut of low into the Tasman is progged with stark contrasting temps between the Bight and Tasman SSTs being the main driver here.

GFS progs the affects of the cut off scenario to deepen over Tues/Weds in the Tasman which could propagate some good swell and more rainfall for Southern NSW/SE Vicco.

 

[Jellybeans]

@POW_hungry Images not working.
Edit: Never mind

 

[POW Hungry]

@POW_hungry Images not working.

Better? Damn XenForo!

 

[Jellybeans]

For Main Range.
GFS = Dusting
EC = 10-20cm
GEM = Dusting
Wait for the disagreement to clear a bit.

 

[POW Hungry]

EC has a big mouth for this time of year... Queue the downgrades.
PERISHER:

 

[POW Hungry]

The wash up for swell next Monday... ~4m swells for Sou-Coast NSW

 

[rocketboy]

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Winter wise this SST set up is basically backwards to what we want - correct?

 

[Jellybeans]

[QUOTE="

Winter wise this SST set up is basically backwards to what we want - correct?[/QUOTE]

No actually I would say that's a good set up. Cool in the Bight to keep temps cool and Warm in the Tasman to add moisture to ECLs and Tasman Lows. Most forecasts including POAMA are for a cooling Bight.

 

[POW Hungry]

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+'tive temp anoms aren't ideal for (snow bearing) frontogensis, but obviously it's hardly close to winter.
Go here for a little read on SST influence on Aussie snow.

 

[Kletterer]

Looks like a good combo for Hotham/Falls/Buller.

 

[POW Hungry]

Looks like a good combo for Hotham/Falls/Buller.

Buller for sure with the SW flow.
Thredbo won't do so bad IF the cut-off lingers off the SE coastline.

 

[Jellybeans]

Buller for sure with the SW flow.
Thredbo won't do so bad IF the cut-off lingers off the SE coastline.

Baw Baw with a SW flow? If the freezing level gets low enough which it probably won't.
Edit: GFS says yes to Baw Baw! 1500m FLs in the area.

 

[POW Hungry]

Still some heavy precip rates on GFS's 18Z run, although not as bullish as last night.

 

[xuěboarder]

I was planning to hike feathertop on sunday, im assuming this will put a stop to those plans?

 

[Claude Cat]

I was planning to hike feathertop on sunday, im assuming this will put a stop to those plans?

It would be sub-optimal. IMO

 

[Untele-whippet]

Buller for sure with the SW flow.
Thredbo won't do so bad IF the cut-off lingers off the SE coastline.

Still MTB season at Thredbo, they will not like.

 

[POW Hungry]

Still MTB season at Thredbo, they will not like.

Long way to go and at this stage it's not something that is likely to produce inconvenient snowfalls to village level IMO.

 

[climberman]

Long way to go and at this stage it's not something that is likely to produce inconvenient snowfalls to village level IMO.

trails go to >1900!

 

[POW Hungry]

trails go to >1900!

...and models are still >144hrs out!

 

[POW Hungry]

System still on track on the latest (12Z) run, although lack of alignment lies in the QPFs. EC upgrading QPFs for Eastern Vic/Sou-Coast NSW and Snowies.

Snow still above 1800m IMO.

 

[POW Hungry]

Thredbo Top Station - Note snow due well after the max of 7C on Sunday.

 

[Jellybeans]

For Main Range
EC = 10cm
GFS = Dusting
GEM = Nothing

 

[POW Hungry]

GFS doesn't seem overly interested in it because of the Tassie Shadowing (straight South system).
EC going for a bit more 'hook'. Next few days should play out well...

 

[jwx]

ens still looking solid.

deterministic/cutoff 540 cell.

 

[Vermillion]

Not too bad, pressure isnt that low so i'm not sure about some of the snowline predictions, at this stage anyway. It's going to rely on cool uppers to get snow on the peaks, but for rainfall it looks great.

 

[jwx]

I agree with the others cc,pow its don't really matter if snows
or it don't at this time of the year. What does matter is the models,
are trending the seasonal switch is knocking at the door.

That said,EC temps down@2 metres suggesting to me atm,
if there is moisture then the snow is on the table.

 

[POW Hungry]

EC & GFS now looking very much aligned for Sunday eve, Monday on the 12Z run.
Good falls back on the cards for a GFS scenario with a more hooky set-up IMO. EC staying strong with this one.
10 cents above 1800m for me.

Worth locking in, in the next day or two.

 

[jungfrau]

EC & GFS now looking very much aligned for Sunday eve, Monday on the 12Z run.
Good falls back on the cards for a GFS scenario with a more hooky set-up IMO. EC staying strong with this one.
10 cents above 1800m for me.

Worth locking in, in the next day or two.

Timing for rain turning to snow (Hotham) is likely evening or during day Sunday?

 

[POW Hungry]

Timing for rain turning to snow (Hotham) is likely evening or during day Sunday?

Somewhere around mid arvo Sunday for Hotham IMO.

 

[Jellybeans]

GFS Freezing Levels are pretty crap, only conducive for snow on the top of the Main Range and maybe Bogong.

EC looks much better with below -20 500mb uppers, showing a clear cutoff low.

And EC snowfall estimates are around 25cm for the Main Range.
Compared to 0cm on GFS and GEM. More time for this to pan out.

 

[jwx]

Canuck ens lining up the low pressure in trough axis, inline with
the other ens atm. Roughly 60+mm precip in the parcel maybe.

 

[cookieman]

Looking promising for 10+ cm on the highest peaks.
Resort marketing machines will go on overdrive for claims of great start to 2017 ski season.
Mountain streams fishing should be very good at Easter weekend after this rain event.

 

[jwx]

GFS 10metre height kts, indicates the low works down to the surface. with gales upto 80/90kms along the coast.

 

[jwx]

Back to the 12z 9th EC is supportive @850mb/700mb is - cold enough.

Note precip increases over the next 12hrs.

All the ingredients are looking good

 

[The Plowking]

Looking promising for 10+ cm on the highest peaks.
Resort marketing machines will go on overdrive for claims of great start to 2017 ski season.
Mountain streams fishing should be very good at Easter weekend after this rain event.

might start a few going upstream

 

[Majikthise]

4 day rule now applies.

 

[Scoober]

BOM says snow above 1200m on Sunday...

 

[POW Hungry]

BOM says snow above 1200m on Sunday...

A very isolated, deep airmass will be the determining factor here. if these -28C temps eventuate @ 500mb then yes, it's likely to snow down to those sort of levels at least. But as you can see it's very localised at the moment:

 

[POW Hungry]

00Z GFS upgrades moisture with the Low lingering around the NSW Sou-Coast on Monday. EC, GFS & The Canadian Model now virtually inseparable on this one.
Some solid coastal falls looking likely IMO.

As for snow I still like it for ~10cm above 1800m, anything lower is a 'bonus' IMO.

 

[POW Hungry]

EC Ensemble

 

[jwx]

Both freezing within the cell,roughly -36c @500mb.

 

[POW Hungry]

GFS going colder again with -28C temps at 500mb, further and wider over the alps. -30C above Bass Straight... Those are mid-winter temps! She's looking colder each day. All over by early morning Monday though.

Swells (& wind) on the south coast are set to be massive. I know a few southern corners that will pump. I am sure @SAsurfa is keeping an eye on this one from AK.

 

[Vermillion]

This encourages me a little less, but for mid April i'm not too concerned about how much snow falls.

 

[POW Hungry]

Considering it's early April, some beautiful temps progged for Sunday eve over the alps.
Nice, moist lower-mid atmos (to about 5k).

Progged sounding is for Thredbo 10pm Sunday:

A few cents in Thredbo village is now likely IMO.

 

[jwx]

12z frosty. Those Trop theta heights are low enough and plenty cold.

 

[Majikthise]

GFS going colder again with -28C temps at 500mb, further and wider over the alps. -30C above Bass Straight... Those are mid-winter temps! She's looking colder each day. All over by early morning Monday though.

Swells (& wind) on the south coast are set to be massive. I know a few southern corners that will pump. I am sure @SAsurfa is keeping an eye on this one from AK.

I drew the attention of my surfing colleaugue to this on Monday. He is already packed .

 

[jungfrau]

12z frosty. Those Trop theta heights are low enough and plenty cold.

Do you have a similar map 12hrs earlier?

 

[Jellybeans]

For the Main Range:
EC still the best of the pack with 15cm
GFS about 5-10cm
GEM Dusting
UKMO looks cold enough for 5cm or so.

Meanwhile EC EFI is not very optimistic for snowfall over the period. But I would use this product with caution.

If you don't know what EFI is:
"The Extreme Forecast Index (EFI) was developed at ECMWF as a tool to provide some general guidance on potential extreme events. By comparing the EPS distribution of a chosen weather parameter to the model’s climatological distribution, the EFI indicates occasions when there is an increased risk of an extreme event occurring"
Source: WMO

 

[jwx]

Do a little better for you 78hrs+
jungfrau

Nice 534 powder line to the S to bad its not winter.
78hrs

90hrs

 

[jungfrau]

Do a little better for you 78hrs+
jungfrau

Nice 534 powder line to the S to bad its not winter.
78hrs

90hrs

Thanks jwx!