Model discussion - hunt for cold Christmas period 2021

[Ali1977]

14 minutes ago, mulzy said:

Tuesday is certainly interesting.  Mogreps snow depth 12 noon on Tuesday shown below.  Still an outside chance but at least there is a chance!

That’s not bad, about 40 percent. The GFS doesn’t really get it going to 1200 so I wonder if MOGREPS gets even better by late Tue

[nick sussex]

Happy New Year to all .

A New Year a New Hope for coldies , the start of a mini -series !

Starting 2022 with some early model disagreements , what’s new !

It certainly looks more seasonal after the very mild recent conditions . Just looking at the ECM ensemble spreads and there’s room for the jet to track further south than the op and the GFS and GEM throw in an early snow tease so not the worst way to start 2022 for coldies .

Although the models want to flatten the pattern out by day ten that’s still some way off .

So peak interest looks like day 3 into 4 and then 7 into 8 when the jet tracks more se through the UK.

[Jason T]

Happy New Year all and to your families, Hopefully a much better year, and looking at the charts a much more wintry feel inbound from now.

[Purga]

A nice blizzard for Central parts on Tuesday? A small shift of that system could make a world of difference to the conditions on the ground anywhere in the country.

Anything from raging blizzard to cold rain to 'what was all the fuss about' !

Exciting though and just goes to show how the weather can really throw up some surprises even in the most 'boring' zonal type set-ups.

PS: Could also be a tad wet !

 

PPS: Oh  - and most importantly - Happy New Year to all you great people on NW ! Here's to a nice snowy one...

Edited January 1, 2022 by Purga

[Ali1977]

Icon keeps the front to our south, as per the ECM - hopefully GFS keeps us in the game 

[Nick F]

Given Tuesday's low running along the south / through the English Channel will have sub-tropical origins, emanating from between Bermuda and the Azores, it will have some warm air wrapped up in it, so think the GFS snow solution looks a bit far fetched, particularly as the other models hold back too far north the cold enough air for snow behind an occlusion moving south as the low arrives in the far south. The deepening of the low less certain though, depends how it engages with the strong jet stream and shortwave trough within it running up from the Azores towards S England.

Edited January 1, 2022 by Nick F

[nick sussex]

Quite a difference upstream with the ICON from just T60 hours .

The others split the energy into two shortwaves , the ICON doesn’t and phases this .

 

[kold weather]

Interesting set-up potential again from some of the 00z models, though I'm extremely wary of any set-up that requires a rapidly deepening low on the sort of track projected, probably 8/10 they end up weaker or south, and either solution will drastically reduce the snow chances down towards 0 for most. We need a deep LP to help really tuck any marginally cold air into the system enough and help the front be as strong as possible to help with evaporative cooling. Any weaker low will likely be further south AND not tuck the cold air in meaning an end game of cold rain instead.

Its a fairly rare set-up for it to happen like the GFS/GEM. The fact both models are known for overdoing LPs also doesn't fuel confidence. However we've not had anything remotely approaching a rare snow set-up since March 2018, so maybe we are overdue a bit of synoptic luck

[Anthony Burden]

3 minutes ago, Nick F said:

Given Tuesday's low running along the south / through the English Channel will have sub-tropical origins, emanating from between Bermuda and the Azores, it will have a some warm air wrapped up in it, so think the GFS snow solution looks a bit far fetched, particularly as the other models hold back the cold enough air for snow behind an occlusion moving south as the low arrives in the far south. The deepening of the low less certain though, depends how it engages with the strong jet stream and shortwave trough within it running up from the Azores towards S England.

Morning Nick,well GEM picked that low up yesterday all credit to the Canadians ,but now what very difficult at this range to get the precise track but a possibility on the northern edge of a serious amount of precipitation.Could of

course all go wrong as before Christmas debacle from computerised charts,but some excitement for cold lovers.

 

3 minutes ago, Nick F said:

Given Tuesday's low running along the south / through the English Channel will have sub-tropical origins, emanating from between Bermuda and the Azores, it will have a some warm air wrapped up in it, so think the GFS snow solution looks a bit far fetched, particularly as the other models hold back the cold enough air for snow behind an occlusion moving south as the low arrives in the far south. The deepening of the low less certain though, depends how it engages with the strong jet stream and shortwave trough within it running up from the Azores towards S England.

 

[Man With Beard]

Happy New Year all, I see the GFS stayed in the pub so late it carried on until the 00Z run - perhaps 20% support from ensembles elsewhere so quite unlikely considering it's D3 - however aside the snow risk, worth pointing out the scenario comes with a major storm risk on the south coast with 80-90mph winds.

However, most likely scenario is a bit of breeze and rain for the south, and a frost the following night

[Tim Bland]

Happy New Year all…Things got interesting again real quick didn’t they!  This is only 4 days away ! 

[PiscesStar]

5 minutes ago, Tim Bland said:

Happy New Year all…Things got interesting again real quick didn’t they!  This is only 4 days away ! 

I noticed the entire south East devoid of any snow potential yet again I see on the charts... 

[Methuselah]

Happy New Year, all. I can view the current GFS today!

[Mark Smithy]

11 minutes ago, Tim Bland said:

Happy New Year all…Things got interesting again real quick didn’t they!  This is only 4 days away ! 

It's incredible how quickly it has developed. Most people wandering out today would be incredulous at the prospect of snow on Tuesday but there it is. Do I believe the GFS scenario? Yes, possibly!

[Man With Beard]

9 minutes ago, PiscesStar said:

I noticed the entire south East devoid of any snow potential yet again I see on the charts... 

Some ensembles pull it further south 

[Tim Bland]

7 minutes ago, PiscesStar said:

I noticed the entire south East devoid of any snow potential yet again I see on the charts... 

I wouldn’t take the snow charts too literally, just indicates we are in with a chance… could end up 200 miles south or north …or just end up as rain, as per Mogreps stamps  above , looks about a 40% chance at the moment of somewhere seeing a decent covering mid week.

[Ali1977]

Very similar at T54 with the front compared to the 00z  although the colder air from the north is 50 miles further north 

Edited January 1, 2022 by Ali1977

[Man With Beard]

2 minutes ago, Ali1977 said:

Very similar at T54 with the front compared to the 00z  although the colder air from the north is 50 miles further north 

This is an F5 moment! It looks like T60 will go the same way...

[Tim Bland]

YES!!!

[Singularity]

42 minutes ago, Nick F said:

Given Tuesday's low running along the south / through the English Channel will have sub-tropical origins, emanating from between Bermuda and the Azores, it will have some warm air wrapped up in it, so think the GFS snow solution looks a bit far fetched, particularly as the other models hold back too far north the cold enough air for snow behind an occlusion moving south as the low arrives in the far south. The deepening of the low less certain though, depends how it engages with the strong jet stream and shortwave trough within it running up from the Azores towards S England.

I believe GFS establishes an exceptionally strong low-level inflow of cold air that undercuts the front a bit, physically plausible but inherently very low probability - it requires a very strong pressure gradient.

[Tim Bland]

Almost all of England & Wales  gets it on this run ! 

Edited January 1, 2022 by Tim Bland

[mountain shadow]

2 minutes ago, Tim Bland said:

Almost all of England & Wales  gets it on this run ! 

According to the BBC forecast I just saw, it will be dry and 7 degrees in London at the same as this!

Zero indication of any snow event anywhere.

[Ali1977]

Proper blizzard there, with strong winds and heavy snow

[Mark Smithy]

Blimey. The 6z really is going for a full-on snow event for England & Wales Monday night/Tuesday morning.

I know our attention will be focused on these shores but meanwhile out in the Atlantic there's the most extraordinary temperature contrast on this run. The weather / climate at the moment seems bonkers:

[Methuselah]

There might be some freezing fog around, midweek, should the ground be sufficiently wet following Tuesday's sleety rain event?