For the snow starved south today has been a massive downgrade. The last two ensemble runs have been downgrades. The 06Z split into two distinct tight groups mild and cold equally. The 12z has gone full blown mild after a decent short cold spell with the mild group joined by the majority of perts. The north however may get some memorable snow which even they haven't had in recent times before becoming milder. There is less certainty towards mild there as well.

Whilst nothing is certain going forward we all know by now what the form horse is and warm flips far outweigh cold flips back. 🙁

GFS looks cold but ECM sees mild. Notably (I only look at the first charts Wetterzentralle shows me - the OP I think)  ECM looks like March 1947 not February 1947.

As ever, keep in your minds the numbers 2024 and 420+.

My guess is cold in the north but warm spells in the south. Plenty of goddam rain too with spring hanging on in southern Europe. I really hope I'm wrong, we really need a sharp frost or few.

The ensemble runs initially had this as a very brief and shallow cold snap. The EC a couple of days ago showed milder air coming in much sooner as well, only to flip back in the next run. Last part of the run tonight is very mild once again, but I'd not be surprised in the least if it were to flip back again tomorrow. 

Regardless, hats of to Q who saw the potential for the upcoming new year cooler spell before even the models caught on. It shows that a real understanding of global weather patterns can trump generic model output. 

That's the frustration with snow in this forsaken craphole: despite us being relatively small (geographically), it's near-impossible to get a snow event covering the vast majority of the country. 

I've been on the happy side of that, and the shitty side.

https://www.theweatheroutlook.com/charts/gfs/18_156_mslp850.png 

a). An 'on the brink' cold op run from the 12z GFS.

b) AIFS which picked up the stronger block before the other models which may add some credibility,  has kept up with the general idea and hints at a scandy high later.

c) Mogreps a little more bullish for cold with virtually half the suite wanting to lengthen the spell.

Haven't looked at the pub run yet, but not a done deal for now.

It was that Atlantic push from the SW next weekend that brought the heavy snow to a band of the country from the Midlands to around Cumbria, then pulled away allowing a fresh southerly flow of cold.

That was my dream scenario.

Scandy Highs usually deliver bobbins-all here.

Yes the cold airmass has advanced some 300 - 400 miles further southwards for the same time. You can compare this to the 12z run here:

12z Op @ +168: - Warm airmass making it into far south west:

18z Op @ +162 - Warm airmass only just making it into southern and central France

Again, be wary of taking each individual operational run at face value. All this (rather wintry) op run shows is that cold options are still very much a possibility in the medium term.

Of course, but for contrasting purposes it shows the uncertainty...

I wonder if this is again linked to another cold blast in the states. That being said, 18z looks better that the last run.

However, @ +150z on the18z GFS ENS shows a mean of -5.2c @ 850 on 5th January 2025

Yet @ +156z on the 12z GFS (Most recent run) the mean shows -1.8c @ 850hpa on 5th January:

18z has trended colder in the ENS mean and it's is more up to date. Are you keeping up with this Brian haha?! 😂 J/K But yes - I know what you mean a lot of model wobbles and a roller coaster!! As much as we all want to look into the future it's not worth looking past NYD in my opinion as you may agree but been so interesting and nice to talk about some "interesting weather."

https://www.theweatheroutlook.com/charts/gfs/18_318_mslp850.png 

The short ensembles are a significant improvement the further north you go.

guernsey

https://modeles16.meteociel.fr/modeles/gensp/runs/2024122918/graphe3_00000_220_250___.gif 

London

https://modeles16.meteociel.fr/modeles/gensp/runs/2024122918/graphe3_00000_311_140___.gif 

Carlisle

https://modeles16.meteociel.fr/modeles/gensp/runs/2024122918/graphe3_00000___-3.11320754717_54.9392712551_.gif 

What's interesting about the 18z is that it will be either cold in medium term or mild - nowhere does it show any of the ENS on the 18z run which are close to the 30 year mean @ 850hpa:

I.e Operational 18z is with one of the coldest ENS runs and control 18z is with one of the mildest ENS runs for London below:

Take a look at the ENS for New York City for instance - not only does it go bitterly cold but the fact NYC gets a cold snap the minute we get a cold snap - you can tell by the uppers for NYC and notice the plunge in upper 850s at around the 2nd of January? - Similar to us me thinks!? Leaving you with the 18z ENS for NYC:

No conclusion is just the fact that a cold NE States blasts up the jet with cyclogenesis from experience and we saw this in February 2021 when the deep cold had an impact on the HLB we were due to have that time, furthermore, the Sates esp the N.E are about to go into a bitterly cold spell as above 18z ens models show at the same time we (UK are going into a cold snap). But how long for will remain the question... we shall see...  

Tong = wrong. But please don’t say you don’t know who Pete Tong is.