Model Output Discussion. 3/12/2022. How cold will it get?

[danm]

1 minute ago, Tim Bland said:

Indeed, produces a fair amount of snow for the north / wales esp high ground.

would selfishly like it to all be further south though and this would increase the longevity of our cold spell for all !

Tbh this is an absolute lifetime away in modelling terms. 

[Kentspur]

8 minutes ago, Tim Bland said:

Indeed, produces a fair amount of snow for the north / wales esp high ground.

would selfishly like it to all be further south though and this would increase the longevity of our cold spell for all !

 North of th

Wheres the dislike button for us southern softies   Its North of the... Thames for me

Edited December 5, 2022 by Kentspur

[Catacol]

2 minutes ago, bluearmy said:

Irrespective of the Azores low saga, the NH profile in week 2 is beginning to grab my attention 

You mean this kind of profile?

GEM returning to this kind of shape more than once now. I still think a Scandy High is going to build but perhaps we can cross fingers it builds AFTER what this is suggesting happens next.

[Derecho]

2 minutes ago, Battleground Snow said:

Cold air is drifting west on the ukmo at day 7.

The low is closing in slowly, somewhere would get a huge fall under that set up 

Yes this Azores low can make things interesting if the UKMO comes off (which is excellent) though the Scandi high is important. 

Good to see the GFS slowing down its approach a bit though without the Scandi high we are exposed to milder air making more inroads, especially from any systems that come in behind the Azores low.

The model output I think has made another turn this morning, from the low staying out rest being a favoured scenario to it now becoming a big player (we still have EC to arrive). The low is forming now so uncertainty should begin to reduce after a few more runs.

Nothing is without its drama when it comes to UK weather model output is it?

[Singularity]

Yeah, confidence is low on where we'll be to begin next week. Take the UKM 00z (left) v 12z (right) for example: A small low dropping through the Greenland Sea (upper-left of image) kicks off a chain reaction that sends the cut-off high eastward to Scandinavia. Hence the situation at run's end looks a lot less finely balanced than it did on the 00z.

GEM 12z is along similar lines to the GFS 00z and to a lesser extent 06z runs, in that it stops just short of feeding the low by the Azores some extra positive vorticity via a breakaway low Mon-Tue. The GFS 12z threw that right across to the big low which allowed it to sustain as a highly organised system for a bit longer. That a significant snow event was still modelled for central UK speaks for itself.

Overall, another very interesting set of runs so far, with a wide variety of details for the UK that affect just how cold conditions are and how much snow falls (...which aren't always positively correlated). Clear that a lot of key moving parts are still to be resolved.

[E17boy]

Yes a lot to be resolved but I pray for that Scandi high as us here in London will fair better with an easterly set up fingers crossed. 

[Johnp]

7 minutes ago, bluearmy said:

Irrespective of the Azores low saga, the NH profile in week 2 is beginning to grab my attention 

In a bad way presumably? Looks like the pv wants to regroup. 

[MattStoke]

27 minutes ago, MATTWOLVES said:

There we have it around day 9 the signs of milder air trying to make inroads North. 

Will it power through?

Will it grind to a halt as the cold air says step aside whimp!

Will it blast that cold air back and say step aside troll from Trondheim!.

Or will it simply not even make the journey here and say sod you blighty I'm off to Jules neck of the woods!

I wish I had the answers but I'm kind of like......

Bank

[icykev]

23 minutes ago, MATTWOLVES said:

There we have it around day 9 the signs of milder air trying to make inroads North. 

Will it power through?

Will it grind to a halt as the cold air says step aside whimp!

Will it blast that cold air back and say step aside troll from Trondheim!.

Or will it simply not even make the journey here and say sod you blighty I'm off to Jules neck of the woods!

I wish I had the answers but I'm kind of like......

Reminds me of storm Emma coming up from the south Matt, buried us over here!

I for one wouldn't mind a repeat with the bitter easterly to follow . . .

 

[Ben Sainsbury]

3 minutes ago, Johnp said:

In a bad way presumably? Looks like the pv wants to regroup. 

Quite the opposite imo. If the GFS is anything to go by, the polar vortex is all over the shop and away from Greenland/Canada, which is the most important thing!

Edited December 5, 2022 by Ben Sainsbury

[Scott Ingham]

Well regardless of where we go week 2/3. Im happy the cold has landed right on cue 5th to the 8th and from a brushstroke forecast back at the end of October!!!! (Just about my best seasonal effort so far)

For what its worth though, i dont believe the drop in AAM is going to hinder us more help as the slight move north in the jet stream caused by this *could* aid in battleground snow!!! 

There after as catacol has posted the next MJO push could see us back in an amplification cycle while we keep the cold with us a week or 2 later into the year and much colder air to tap into from the north east

Edited December 5, 2022 by Scott Ingham

[MATTWOLVES 3]

4 minutes ago, icykev said:

Reminds me of storm Emma coming up from the south Matt, buried us over here!

I for one wouldn't mind a repeat with the bitter easterly to follow . . .

 

Don't you get hogging all the snow again kev! I was on snow patrol for 24hrs out that day and ended up wanting to catch a quick ferry to Ireland

So many options on the table though and gr8 to see so early on.

[Penicuikblizzard]

43 minutes ago, MATTWOLVES said:

Very frigid air lurking too the NE by day 6 on the UKMO run.. I've noticed Exeter mention this milder attempt from the SW further on could bring widespread snowfall on the leading edge,but there is uncertainty over the timing and whether it even makes those inroads! Hence the low confidence in conditions for the 2nd part of the month! The outlook is far from nailed down and that Low is gonna be causing the big headache. Lots going on in the short to mid term though.

Would’nt take much adjustment to open the floodgates from the east….a lot of potential here 

[Derecho]

GEFS mean is slightly colder at T192 funnily enough.

[Mike Poole]

Run of the day for me is the GEM, because of the locked in nature of how it ends, all the PV is essentially over to the Asian side, and potentially coming directly at us!  There is nothing left to speak of on the American side, and zero, zilch, nada from the Atlantic.  And we are already well and truly in the freezer by this point.

[Kentspur]

6 minutes ago, MATTWOLVES said:

Don't you get hogging all the snow again kev! I was on snow patrol for 24hrs out that day and ended up wanting to catch a quick ferry to Ireland

So many options on the table though and gr8 to see so early on.

I'm actually visiting Cork, Eire on 18th to 20th with my lil bro it will be sods law we get a Thames streamer then Anyway back to the models... 

[Anthony Burden]

Evening all,GFS 12z/GEM all producing these pin ball lows from around the Azores to make the southern half the U.K. the battle ground for less cold 850 hpa .Not sure that I am on the same wave length the very cold heavey airstream well established over all of the U.K. will be very difficult to push away before these lows start to fill and weaken,we shall see great watching all set for the ECM.

 

[Frostbite1980]

Some lovely ens at 192, just a few I have cherry picked.

 

   

 

  

 

  

 

  

[Battleground Snow]

8 minutes ago, Quicksilver1989 said:

GEFS mean is slightly colder at T192 funnily enough.

Yes under -6 out to day 9 is quite impressive for duration, the warm uppers keeps getting pushed back.

You can also start to see the scandi options popping up in the ensembles, I have my doubts the low will ever make it near our shores.

 

Edited December 5, 2022 by Battleground Snow

[weatherguy]

I'll likely save a more meaty post for later when the ECM comes out, but just wanted to point out this chart at +78h from the GFS:

There's not too much ppn showing up, strangely, but that kink combined with the unstable air in the trough really ought to see some decent accumulations of snow in places as we move through Thurs-Fri.  

[BlueHedgehog074]

2 minutes ago, Quicksilver1989 said:

GEFS mean is slightly colder at T192 funnily enough.

Indeed. In fact, compared to even the GFS 00Z ensemble mean, the -5*C 850 hPa temperature line is a fair bit further South-West over the UK. And the mean Low to the South West has quite a squashed, slidey look to it:

The above from the 12Z GFS mean compared to both the 00Z and 06Z GFS means below:

GFS 06Z mean

 

00Z GFS mean

 

All for Tuesday lunch time next week.

[winterof79]

Sometimes in these scenarios its as simple as this;

If a model doesn't predict as much snowfall over the interior then going forward it cannot plot the low temps that would occur,therefore its forecast of the depth of our cold pool is incorrect and allows the milder air in too quickly.

Very simple but also very feasible .

[Crackerjack]

8 minutes ago, Mike Poole said:

Run of the day for me is the GEM, because of the locked in nature of how it ends, all the PV is essentially over to the Asian side, and potentially coming directly at us!  There is nothing left to speak of on the American side, and zero, zilch, nada from the Atlantic.  And we are already well and truly in the freezer by this point.

If Gem did beer Matt, oh wait they do  

[booferking]

Jma bringing in an Easterly end of the week with some  air not far away.

[Howie]

4 minutes ago, Battleground Snow said:

Yes under -6 out to day 9 is quite impressive for duration, the warm uppers keeps getting pushed back.

You can also start to see the scandi options popping up in the ensembles, I have my doubts the low will ever make it near our shores.

 

Yup, few days ago some models had the low zooming through as soon as this weekend, now it's mid to late next week. A definite sign the cold is putting up more of a fight