Model output discussion - Christmas approaches

[Kasim Awan]

Just for fun.. ecm 96h & start of the January 1881 historic UK cold spell (2 weeks with an avg CET of -4.6C)

[Singularity]

57 minutes ago, Man With Beard said:

This is reminiscent of a NH profile after an SSW. Have I missed something? Has there been one?

It’s a bottom-up attack that affects the lower stratosphere only. Same style as in Nov 2010 but likely not as extreme in terms of outcome.

Reliant on feedback mechanisms that are tough for models to resolve in advance. In 2010 we had the North Atlantic SST profile helping out too, this year we don’t. 

Interesting possibilities afoot. I remain focused on the broad picture, keeping in mind that model shortfalls in handling trough disruption are within the dynamics, not based on initial conditions, so can skew whole ensemble suites the wrong way.

[NewEra21]

For anyone worrying about snow, snow depths etc etc. 

I can't remember 100%, but at some point last winter or even the winter before. A 12z ECM run on a monday for the upcoming Saturday had the midlands/EA as the prime spots for snow. Every single day it then got adjusted further and further south, the front barely made it to northern France eventually. So not saying that will happen again, but I wouldn't be surprised at all.

[TSNWK]

On 16/12/2021 at 21:01, NewEra21 said:

For anyone worrying about snow, snow depths etc etc. 

I can't remember 100%, but at some point last winter or even the winter before. A 12z ECM run on a monday for the upcoming Saturday had the midlands/EA as the prime spots for snow. Every single day it then got adjusted further and further south, the front barely made it to northern France eventually. So not saying that will happen again, but I wouldn't be surprised at all.

Yes it was around turn of the year… area interest drifted south run by run until about 72 hours out when it landed 300 or miles south than originally progged… there are many other examples and there’s a theme of southerly corrections….

Be nice to see ecm swing back a smidge south in the morning….. as one thing we don’t want is a northerly correction to start trending..

 

 

 

 

 

[Ali1977]

I’ll start us off. WAA a little stronger up through towards the pole on the ICON. I’ll take that as a small positive - also not the area of heights is a big stronger behind the little shortwave on the east which could help push it a little further south 

Edited December 16, 2021 by Ali1977

[Ali1977]

At 120 the trough in the Atlantic is also weaker and held west slightly - just minor changes 

Edited December 16, 2021 by Ali1977

[Snowman.]

2 minutes ago, Ali1977 said:

At 120 the trough in the Atlantic is also weaker and held west slightly - just minor changes 

Norwegian low is a smidge further S and E slightly weaker. Still nothing like the GFS.

 

Edited December 16, 2021 by Snowman.

[Methuselah]

Talking of a 'Dickens winter', the hoped-for slidergate scenario comes a bit like the ghost of winters past:

From experience, would-be sliders tend to do one of two things; either they deepen and move northeastwards, taking mild air with them -- or they don't deepen at all, run ESE through southern counties and produce nowt more than a little rain/sleet/snow to areas south of the M4 Corridor? Sometimes though (like on Xmas Eve 1968) a depression will remain deep enough to maintain good levels of precipitation and stay on a more southerly track. . . BINGO!

[MATTWOLVES 3]

Here it is in glorious technicolour.

It's a good EC46 tonight...we have blocking here,blocking there,blocking blooming everywhere at various points...not zonal about the way forward...perhaps an Exeter change of words moving forward before much longer.

[Mike Poole]

7 minutes ago, Ali1977 said:

At 120 the trough in the Atlantic is also weaker and held west slightly - just minor changes 

Hmmm, that cross polar ridge looks more likely on the 18z though.  This idea has appeared today on the models, that the trop vortex could be totally marmalised without a SSW or anything from the strat.  I’m not sure what it means yet but if it gains traction (as it seems to be doing as fast as omicron) we will have to consider how it might affect the UK.  Longer term, would probably put us all in the freezer, shorter term, may limit the cold to the northern half of the country.  

Let’s see what the pub run has to say.  Very interesting times!

[Eagle Eye]

Sneaked a look at the ECM members and control run
Merry Christmas is all I can say 


And a happy new year



Some of these are the same members at different times but still, just crazy
 

[tight isobar]

The 12z 2m plots are by far the best yet and extends into January

[Premiere Neige]

17 minutes ago, Ali1977 said:

At 120 the trough in the Atlantic is also weaker and held west slightly - just minor changes 

PV doesn't look far from being ripped in 2 here. In terms of the rest of winter, would that be a K.O. or just an 8 count?

[LRD]

43 minutes ago, Kasim Awan said:

Just for fun.. ecm 96h & start of the January 1881 historic UK cold spell (2 weeks with an avg CET of -4.6C)

Probably one or two on here that remember that 1881 spell very well!

Good spot that. I think we have to take our warmed/warming climate into account though

[Mike Poole]

6 minutes ago, Premier Neige said:

PV doesn't look far from being ripped in 2 here. In terms of the rest of winter, would that be a K.O. or just an 8 count?

Not a KO - because the strat vortex is strong and it would put the trop vortex back together again eventually, but like on ECM, it is a very interesting development today and one I wasn’t expecting on the models, to be honest.  

GFS out to T6 - gets later and later, I’ve got to go to work in the morning.  Actually scrub that I have to work from home tomorrow and don’t have any meetings so is all good!

Edited December 16, 2021 by Mike Poole

[Chesil View]

1 minute ago, LRD said:

Probably one or two on here that remember that 1881 spell very well!

Good spot that. I think we have to take our warmed/warming climate into account though

Yes very true, today's  warmer air can hold more moisture so when forced aloft by rising up over the cold block would actually produce more snow than back then. Lol

[LRD]

1 minute ago, Broadmayne blizzard said:

Yes very true, today's  warmer air can hold more moisture so when forced aloft by rising up over the cold block would actually produce more snow than back then. Lol

Ha ha! Very good! Have a Xmas like

[Uncertainty]

33 minutes ago, MATTWOLVES said:

Here it is in glorious technicolour.

It's a good EC46 tonight...we have blocking here,blocking there,blocking blooming everywhere at various points...not zonal about the way forward...perhaps an Exeter change of words moving forward before much longer.

Worth a fanfare in 90% of winters @bluearmy and @knocker

Regardless of your regime preference!

Looks like less of a risk of a Wbased -NAO? I’m more worried about it simply being too small and weak, 1020mb even if its over E Greenland might not be enough to put the U.K. on the fun side…

The DJF seasonals would be in serious trouble though if those anoms above came off…

12z EPS  flip back like yesterday but I think I echo @Ed Stone’s sentiment that historically  either the Atlantic barrels though and the block is weaker and too high NW (please no) or the low disrupts underneath the block leaving a weak slider trending ever further south. Ec 0z and GFS 12z found the sweet spot snow wise. The sinking high option seems to have faded though…

Also the back end of the NAEFS, GEFS and GEPS signals are really quite striking

 

Key difference is the enhanced Siberian high on the GEPS and perhaps GEFS. Vortex pressure for later in Jan perhaps? Regardless, the blocking/Wedge over Greenland still looks pretty strong even this far out.
 

No reason to think there won’t be more cold chances after we sort out the angle of attack from the Christmas low…

Edited December 16, 2021 by Uncertainy

[MJB]

Very similar to what the Beeb have just shown but the LP to the SW was further South , interesting times 

[TanHillWeather]

GFS at 72hrs, very little change on previous run. Wonder if we will see it move towards UKMO/ECM on this run.

[ICE COLD]

Just now, MJB said:

Very similar to what the Beeb have just shown but the LP to the SW was further South , interesting times 

That’s because they used this mornings ECM run 00z

[Sweatyman]

On 16/12/2021 at 22:00, MJB said:

Very similar to what the Beeb have just shown but the LP to the SW was further South , interesting times 

Mad! Why would the Beeb wanna show an Xmas day graphic already! Suckers!

[Staffmoorlands]

Big 18z tonight

[Mike Poole]

Pub run T96:

But I can see this vortex ripper scenario on this one as well, let’s watch and see…

[frosty ground]

The high looks like it’s following the earlier days runs