Model output discussion - Closing in on Christmas

[frosty ground]

Low heights over Spain pressure rising over Scandi, 

[Matt H]

Some decent uppers on this run as well, I’d be very grateful if we could pull this off over the Christmas period.

[Bartlett High]

Why can't this happen?

[IDO]

GEM makes a dog's dinner out of the Atlantic sector, blowing up lows and probably struggling at the moment as it does not look likely. However, the synoptic is similar as there is good ridging upstream just thwarted in the Atlantic by some shenanigans:

 d10 gem 12z> 

[TSNWK]

Oooo I was going to stop at 288.. but stuff it, seems rude when this is starting to be served up..

 

[Duane S.]

When the models show cold by any route we are usually in business. Not aways of course but it's a great sign.

[Zak M]

9 minutes ago, Tim Bland said:

Where is that low to the north west heading ️

To the Bay of Biscay.

In all seriousness Tim, this is a very good run. -8c uppers into southern parts of the UK and look how far south the jet is:

   

[phil nw.]

I thought like others it would be better to see some energy heading south to create an Azores low which would see the high hold  up.It seems however which ever way the jet splits upstream the Atlantic ridging holds it's ground for a while and on this run we low pressure then heading se.

Good signs as usually we see the GFS with it's tendency to throw most of power of the jet north and wanting to flatten any ridging.

The earlier ens had us keeping the cold after Christmas so you never know this may end up more than a 48hr toppler.

Of course this is just for fun at this range but good signs along with the general NH profile.

[Vikos]

Well, Santa might be freezing on this one

 

[Allseasons-Si]

The Eagle has landed for Christmas day...

another good run from the gfs but i am wary of that ESB low and how it behaves, until that is modelled right then we need to be cautious from there as it may scupper our chances of getting a more amplified pattern in the Atlantic and trough/s dropping into Scandi. 

[andymusic]

north sea snow making machine up and running on this run

[johnholmes]

6 minutes ago, Allseasons-si said:

The Eagle has landed for Christmas day...

another good run from the gfs but i am wary of that ESB low and how it behaves, until that is modelled right then we need to be cautious from there as it may scupper our chances of getting a more amplified pattern in the Atlantic and trough/s dropping into Scandi. 

Forgive my ignorance but what is the ESB low please?

[LRD]

1 minute ago, johnholmes said:

Forgive my ignorance but what is the ESB low please?

Eastern Seaboard I think

[Zak M]

      

Day 16 from the 12z GFS... -8/-9c uppers present for the majority and some snow about... as if it will verify

Edited December 14, 2020 by Zak M

[Allseasons-Si]

2 minutes ago, johnholmes said:

Forgive my ignorance but what is the ESB low please?

Eastern seaboard  John

upto 144hrs there are differences in positioning/phasing issues that need to be sorted.

[Kentspur]

The CFS is again showing a snowy Beasterly in between Christmas and the New year following the 0z run❄ not a fan of those dry Northerlies down south although it looks good for Scotland on the likes of GFS in the slightly nearer term

 

 

 

Edited December 14, 2020 by Kentspur

[Tim Bland]

I would normally just laugh at the CFS but after that GFS run and the way the ensembles are headed, I wouldn’t be that surprised!!

[Chesil View]

Interestingly tonight's 12z follows this morning's 00z  wintry control run out to 360. 

[Kirkcaldy Weather]

4 minutes ago, johnholmes said:

Forgive my ignorance but what is the ESB low please?

It’s the main area to watch over the next week or so, it’s the big nor’easter,snowstorm which is set to impact the NE USA on Wednesday/ Thursday (see my snow and ice twitter thread) we have seen these systems cause quite a bit of confusion among the models over the years usually 2 options either it can go north as it moves across the Atlantic and bring the more typical Atlantic wind and rain (similar thing happened a few winters ago with the failed easterly ) or it can go to the south / south west of the UK and that’s usually something I keep a look out for as majority of the time u get a pressure rise to the north and can lead to an easterly - right on cue the latest gfs hinting at that. 

[nick sussex]

Looks like the models are in a mood to drag out the drama with a shortwave mess over the UK , phasing issues before that eventually clears sufficiently east se allowing colder air se wards.

I don’t like this type of evolution because it’s a bit of a high wire act and far too stressful for coldies in here.

However if it’s to be that evolution and you get to the other side having pre -ordered your new ear muffs, gloves and Santa hat then it might be a case of needing two goes to get the deepest cold air south eastwards.

You can see from this mornings ECM and tonight’s GFS one go at getting the cold south and then a shortwave to the nw which then tracks se’wards.

This type of evolution isn’t that common . Generally you want that shortwave to remain a shallow feature and as that tracks se you’d normally then see pressure rising towards Greenland behind it . The reason here is that the shortwave moving se is a response to renewed amplification over the eastern seaboard of the USA .

Its quite rare though in the UK to get the timings right re a festive cold spell . So the stakes are quite high because there’s something really magical about having the weather which fits those lovely Christmas card scenes .

Anyway lots of runs to get through and it’s a rather longwinded evolution so best be cautious . 

Lets hope the ECM plays Santa and not the Grinch tonight ! 

Edited December 14, 2020 by nick sussex

[Valleyboy]

20 minutes ago, Allseasons-si said:

The Eagle has landed for Christmas day...

another good run from the gfs but i am wary of that ESB low and how it behaves, until that is modelled right then we need to be cautious from there as it may scupper our chances of getting a more amplified pattern in the Atlantic and trough/s dropping into Scandi. 

Not sharing the enthusiasm for a mediocre northerly.  Always looks great on paper but they rarely deliver.  I’m looking for future upgrades, to something giving more of an eastern promise.

[Tim Bland]

4 minutes ago, Valleyboy said:

Not sharing the enthusiasm for a mediocre northerly.  Always looks great on paper but they rarely deliver.  I’m looking for future upgrades, to something giving more of an eastern promise.

Have you seen the rest of the run...it goes on to an Easterly. Are you holding out for the winds go immediately from Westerly to Easterly?...you will have a long wait

[Methuselah]

Oooooooooh!!! Gets good at Day 10, as usual, and stays that way, throughout. Let the countdown commence!

    

    

Houston, we have potential!

[alexisj9]

40 minutes ago, IDO said:

GEM makes a dog's dinner out of the Atlantic sector, blowing up lows and probably struggling at the moment as it does not look likely. However, the synoptic is similar as there is good ridging upstream just thwarted in the Atlantic by some shenanigans:

 d10 gem 12z> 

Unfortunately the little low could still do this, let's just hope not, all depends on when or if it phases with our jet stream.

[Allseasons-Si]

The control run is very similar to the gfs for Xmas day...

again with the control,it looks like a slider/neg tilted trough out in the N Atlantic looks like disrupting SE like the gfs did.