https://images.meteociel.fr/im/17/2203/gfs_0_312ebj4.png 

The control at first glance looks similar, with high pressure to the SW and south, but there's somewhat colder air over the SE half of the UK. Winds are lighter westerlies compared with the operational run.

The ensembles continue to be mixed. This morning's options include:

Cyclonic SW'lies or WSW'lies: 7

Ridge to west with westerlies: 6

Ridge from east over UK: 3

Ridge from south over UK: 2

Complex lows to the NW, north and NE, cold westerlies and WNW'lies: 2

Complex low over Scandinavia, cold NW'lies: 2

The rest include a Scandinavian High, a low to the south with weak easterlies, a trough crossing the UK and a North Sea low, amongst others.

A westerly flow remains the most likely option, with a few of the members continuing to show colder weather from a northerly quarter.

Today's standout is number 5, which has snow falling and settling for the vast majority of Scotland, Northern Ireland and northern England, with snow falling further a bit further south too.

https://images.meteociel.fr/im/97/10407/gens_5_1_312cio9.png 

Number 29 is also worth a mention - it has a Scandinavian High with snow falling and accumulating across the far SE on Christmas evening into Boxing Day.

https://images.meteociel.fr/im/37/20981/gens_29_1_312ehe7.png 

 The current run is on the stronger side, chance are the next run will be on the weaker side.    All to play for .

Just for fun, the snow cover chart for the Saturday after Xmas, since it’s the consequence of a reasonably sustained cold snap.

https://www.meteociel.fr/modeles/gfse_cartes.php?ech=384&code=0&mode=16 

Yes, the zonal train is set in now, and really there is nothing tangible that can disrupt the jet and allow a block to develop. 

GFS will continue to thrown out the odd straw to clutch, but realistically its looking like another green and miserable Christmas for London and the SE. 

Still far too far out to be confident on Christmas Day, I would say - you wouldn't trust any charts at day 10, and we're still 13 days away from the big day!

It's good to see such a wide variety of synoptic situations presenting themselves, even if, as you'd expect at this range, westerlies are in the majority.

JFF (and it'll no doubt disappear on the 12z), but I'd not turn my nose up at this!

https://www.theweatheroutlook.com/charts/gfs/06_264_preciptype.png 

Thats a classic NW erly for me haha, i even have a whatsapp group with some mates called "Cusp" becuase we always are... NWales coast nxt to sea, is fine  but Wirral: nope.

Remember the good old fashion 3-4 day northerlies,NW first then show showers transferring to Eastern side...dont happen like that anymore

Alas, the M4 snow barrier seems to be in operation.

Have a look at the 12z GFS - it shows a potent northerly plunge with plenty of snow around, even reaching down here by the 27th.

Where you seeing that so soon?

yeh rather than digging in, they seem to bounce off an Atlantic High

I'm assuming Wetter? (I rarely use it!)

You're spot on there, of course! I wish I had a secret way to know what was coming up in the next model run. 😂

GFS charts appear more or less in real time on TWO, Wetter and Meteo among others. They start appearing at about 15:35 GMT, although delays occur at times.

could this be the first back to back run of cold theme for Xmas we are seeing?

There's quite a contrast to yesterday's 12z, where the AH was centred between the Azores and Biscay and large enough to cover the south of the UK.

I used MC, but it's updating on TWO below:

https://www.theweatheroutlook.com/twodata/gem.aspx 

EDIT: And the 0z ECM AI (but not the op) had a low zipping across the UK in cold air on Christmas Day. Definitely raises an eyebrow, I'd say!

Were such a set-up to verify later this month as suggested by some models, I am far from sure that any wintry precipitation would be entirely confined to high ground.