Reflective reversal they call it

https://www.wetterzentrale.de/topkarten.php?map=1&model=gfs&var=1&run=6&time=336&lid=C00&h=0&mv=0&tr=6#mapref 

That's IMO this is a very likely scenario of how a low West of Greenland could evolve despite frigid cold air entering the Eastern USA...after recent seasons everything points to a revamped jet stream W to E which is the favoured option but it would be nice to see that energy rush northwards west of Nuuk instead ..the spoilers for UK still remain heights to South West and a weaker polar vortex to out NE....Still think this winter could deliver

UkMet develops it to the Southwest with a period of very strong winds (top gusts in the high 90s) with snow above about 300m. True blizzard conditions for the Southwest moors if it comes off.

Arpege delays the development slightly and has the strongest winds (60mph) as it exits the SouthEast. Again there's a period of snow over high ground - Chilterns chiefly - which would give a period of blizzard conditions. 

Still a long, long way until Saturday but definitely one to watch.

Edit: My eye candy has disappeared from the 15z - nice whilst it lasted though!

https://www.wetterzentrale.de/topkarten.php?map=1&model=gfs&var=1&run=12&time=360&lid=P11&h=0&mv=0&tr=6#mapref 

That aside, as Dave has said, this coming weekend is worth keeping an eye on for a variety of reasons. It could be very unsettled, especially in southern parts.

I experienced similar conditions in 2020, albeit in Feb. The drip drip was rapid, although temperatures climbed to around 4C I think.

With regard to your point about the models, I’ve noticed that often (though not always) the pattern shifts northwards as the lead time shortens. I don’t know why that is the case. I should also add that I’m talking about the North Atlantic–Europe region, and it may well not be true in other parts of the world.

Looking at the FI of the ones that go out past t+240...

The 12z GFS op isn't great (but isn't a million miles away)

12z ECM is better

12z AIFS is actually rather good

One of the signs I look for is LP systems getting past the prime meridian into Scandinavia, preferably with a build of pressure across the mid-Atlantic.   A secondary LP running into the southern North Sea is even better.  Some signs of all of these in recent output.

Still mild (in the old fashioned sense) but wetter and windier. Not exactly a win.

I remember in the 80s when Winter temps reached 13c it was newsworthy.  Now its just a given

The 0z zonal wind chart now shows a very brief reversal - but a reversal all the same. There are hints of a second slowdown later in December, but it's only showing as a dip rather than anything more interesting at the moment. 

The ECM weekly charts continue to show a mild December, moreso in the first half, across the UK. The only white on the map is over the ROI/NI in the final week, i.e. January. 

The 12z op had the smallest SSW possible - just one frame, and a value of -0.1!

https://users.met.fu-berlin.de/~Aktuell/strat-www/wdiag/ec.php?alert=1&level=10&forecast=f72&lng=eng&hem=nh 

FAX - fronts and troughs crossing the British Isles from the SW under the direction of an LP moving from mid-Atlantic to N Norway, 960 mb as it grazes N Scotland on Friday. As it decays, N-lies for most of Britain but a local and intense LP runs along the Channel 991mb Sat 29th.

GFS Op - takes the 'local' LP further N, across the Irish Sea. then a repeat of all the above with another local LP 985mb Irish Sea Tue 2nd, and yet again (!) 975mb Fri 5th. Then back to W-lies with LP never far from N Scotland, and sometimes dipping into the N Sea with a burst of NW-lies e.g. Mon 8th and Wed 10th.

ECM - looks very much like GFS

AIFS - London, maxima often 10C+, briefly lower Sun 30th and Sat 6th, rain from time to time, heaviest Mon 1st. Edinburgh, very mild Thu 27th else maxima mostly 5-6C, rain frequent in the first week, less likely later

GEFS - in the S, mean a couple of degrees below norm Sun 30th and Thu 4th, else near norm through to Fri 12th. Rain from Sun 30th onwards, heaviest around Fri 5th. In the N, temp profile similar though with a big drop from unusually mild Thu 27th to rather cool Sun 30th, rain on many dates but not specially heavy except in the west (W England also has occasional days with heavy rain)

Talking of lead drop and I know off topic, but has anyone noticed there was excellent progression of leave fall up until that very mild period in first half of November. It’s notable now that some trees here in London have still not lost all their leaves.

That would be a pretty vile day for East Anglia - heavy rain, gale force north / northwesterly and a temperature of 3 or 4c. Imagine being up at the Roman Camp just outside of Cromer - 103m up, on the coast and fully exposed - bitter!

Saturday/Sunday is definitely one to keep an eye on still as the models get a better handle on this little feature. 

Edit:

Having had a quick look through the models it seems there are 2 camps. GFS and Arpege bring the storm in earlier and it tracks further north affecting whereas ECM, Gem and ICON take longer to develop it and a much more southerly track with affects felt more to the South and East.

At t+300, I'm willing that energy from the low SW of Greenland to slide SE'wards into Europe, so that that high tou our north can retrogress and ridge southwards behind it.

https://expert-images.weatheronline.co.uk/daten/proficharts/web/en/ec_aifs/2025/11/26/basis06/euro/pslv/25120818_2606.gif 

And it does start to slide..

https://expert-images.weatheronline.co.uk/daten/proficharts/web/en/ec_aifs/2025/11/26/basis06/euro/pslv/25120906_2606.gif 

But the bloody AH thinks "oh no you don't!", ridges eastwards into mainland Europe, and nudges the low further northwards over us....

https://expert-images.weatheronline.co.uk/daten/proficharts/web/en/ec_aifs/2025/11/26/basis06/euro/pslv/25121012_2606.gif 

...before the AH links with the high way to our east, cutting off the slide of the energy

https://expert-images.weatheronline.co.uk/daten/proficharts/web/en/ec_aifs/2025/11/26/basis06/euro/pslv/25121106_2606.gif 

The only bright spot is that pressure remains high to our north, so chance of another go

And, of course, this is the far-reaches of one run from one model.

(Apart from jam 'Tamara')

https://images.meteociel.fr/im/46/16562/gfs_0_378lug8.png 

ECM-45 wise it's an improvement for cold fans. The SSW is a bit firmer now, still a very brief affair but still below zero, and the outlook for most of December has flipped back to normal rather than a fair bit above as we've seen just recently.

The potential SSW is only a couple of days away, and hopefully it'll actually come off - if nothing else, it'll be interesting to see whether we do get a more normal spell (temperature wise) as a result of it. 

EDIT: And last night's 12z op only went down to +0.1 m/s, so no SSW there. 

FAX: starting with W-lies as a deep depression runs past N Scotland, with winds turning to the N as it reaches Norway on Saturday. At the same time, this cold from the N and mild to the SW wind up a local (and stormy ?) depression crossing S England 993mb later on Sat. Then back to an Atlantic LP 965mb pushing a warm sector and fronts across Britain on Monday.

GFS Op: places less emphasis on Saturday's LP showing only a shallow trough (it had a proper LP yesterday), then LP near NW Scotland with strong W-lies (but not really affecting the SE) until Fri 5th when a separate LP breaks off 970mb Ireland, moving to the N Sea and deepening for a while. By Thu 11th this LP has filled but opened the gates to a powerful LP from the NW 970mb off NE Scotland with cold NW-ly gales for all

ECM: also downgrades Saturday's LP . This model follows GFS with generally unsettled W-lies for the week but keeps the LP on Fri 5th out on the Atlantic, moving across Britain on Mon 8th. Then a big difference, going back to LP near NW Scotland and the usual strong W-lies, nothing particularly cold from the NW.

GEM also sticks with LP near NW Scotland and variations on a persistent W-ly theme, like ECM

AIFS: London, maxima around 10C, a little milder later in Dec, rain frequent and moderately heavy. Edinburgh, maxima around 5C, milder now and again later in Dec, rain on most day but not particularly heavy

GEFS: a colder dip Sun 30th (esp in N) but otherwise mean close to norm, a little rain at first but becoming heavier and persistent through to Sat 13th, heaviest in S and W

Looking at the GFS ensembles, they're a thing of beauty compared to what they've been like for most of the year.

https://www.theweatheroutlook.com/twodata/gefs.aspx?run=na&lg=850&lglocation=dublin&charthour=006&chartname=ps_500hpa&chartregion=na-region&p=1&charttag=PS%20500hPa%20 (GPDM)

Nothing spectacular, no snow fest but mostly below average.