Biggest area of contention for the Christmas period (within at the EC 'spread') is to the west of Ireland. 

That contentious trough is as likely to go the way of the GFS (more N) as the ECM (more south) or somewhere in-between in the run up to and over the Christmas period.  This uncertainty is pretty typical at this range though but nail biting all the same. 

For those looking for interesting trends (in other words, signs of hope to cling on to), look at the SLP averages. Not the absolutes as these are of little point on their own, but the trends in the last three runs. Somewhat hidden away in the last three runs is a trend/signal for a pressure rise Iceland/Greenalnd at t240 and a sinking southwards/elongating of the mid Atlantic low

1800 run from last night

https://www.wetterzentrale.de/en/topkarten.php?map=1&model=gfs&var=1&run=18&time=240&lid=AVG&h=0&mv=0&tr=24#mapref

0000 run

https://www.wetterzentrale.de/en/topkarten.php?map=1&model=gfs&var=1&run=0&time=240&lid=AVG&h=0&mv=0&tr=24#mapref

0600 run
https://www.wetterzentrale.de/en/topkarten.php?map=1&model=gfs&var=1&run=6&time=240&lid=AVG&h=0&mv=0&tr=24#mapref

To be fair the short GEFS have trended colder when compared to the previous 2 runs:

https://www.meteociel.fr/cartes_obs/gens_display.php?x=&y=&run=6&ville=Londres&lat=51.5085&lon=-0.12574&runpara=0&ext=0&type=0

You can toggle between the current set and the previous 3 sets on this link.

And with reference to Mogreps - it wobbles around as much as any other model so don't put too much faith in it.

Misplaced his tea leaves?

6z GEFS just about show a colder cluster holding dominance.

I'm still not entirely comfortable with any of this though. 

https://www.wetterzentrale.de/en/show_diagrams.php?geoid=49909&model=gfs&var=5&run=6&lid=ENS&bw=1

That's true, but following that mantra takes away a lot of the pleasure on the rare occasion when something decent actually verifies! 

I'm still clinging to the fact that the BBC automated  has a sleet symbol for Christmas Eve for here!

Yeah that was an exciting few days lol! 

Yes exactly - there is a cold cluster now appearing around the 24th and 25th? - ENS 850 mean is -4.1c in the 06z run compared with -1.0c on 24th in the 00z ENS run. in the 06z run the Operational is yet again the mildest option or a liar (out-lier). Also precipitation spikes have  reduced or being are being further delayed since this mornings 00z ENS run.

Will the cold cluster of uppers intensify in the 12z and follow the ECM or GEM? - We shall see...!?

To compare - here with the latest 06z ENS run:

This mornings 00z run - Look at precipitation spikes: - Far more and there was no cold cluster around 24th/25th. 

MOGREPS should be used as a 36 member time stepped ensemble (recommended by the UK Met). However, here is the latest 6z update.

(Snow depths here https://www.theweatheroutlook.com/twodata/mogreps.aspx?run=latest&pschartname=snow_depth&pscharthour=198)

Compared to the 18Z yesterday it is a big swing to the mild end. First letdown of the winter, no doubt the first of many in the 2021-22 rollercoaster 

March is looking pretty tasty on the CFS 

2112 hours is starting to get towards the edge of the reliable time frame though.

Quite a lot of scatter! South could either see maxes of +1 or 2c or it could swing mild and we could see maxes of +11 or +12c. Still all to play for and been an interesting time for model watching, but this roller coaster - when will it end and we see some certainty?

Rob - yes milder unfortunately however the GFS 06z Operational is a milder outlier as has often been the case, but will see if GEM and ECM follow suite later so all eyes on the 12z run.

https://www.wetterzentrale.de/en/show_diagrams.php?model=gfs&lid=ENS&var=2&bw=1&geoid=49069

not often you see such wide scatter as these 

Yes true despite the Op being a mild outlier, however my attention is now focused on this cold cluster of ENS between the 23rd and 26th - As this wasn't showing in the 00z ENS which you can see here:

https://www.wetterzentrale.de/en/show_diagrams.php?geoid=49069&model=gfs&var=2&run=00&lid=ENS&bw=1

Now compare with above the 06z ENS - you posted will see the cold cluster appearing around 23rd -26th.

So will this cold cluster of uppers intensify or was it a one off...? we shall see?

Where is Doc and Marcus these days?

Interesting - and a confirmation of the general picture of milder air encroaching from the south or south-west v the block keeping it further south.

Of course, a mere 300-400 miles when we’re still over a week away is very little in terms of the air masses and energy in play.

Just looking at the 00z ECM from N.Hemisphere view - this looks quite an impressive block and indicative of a -NAO and AO:

Those Atlantic systems just stall and disintegrate. 

ICON first of the 1200 out of the blocks to t168. An improvement for those looking for seasonal cheer on previous recent ICON runs, but not definitive. Significant deep cold building to the NE on this one

ICON first of the 12Zs out the traps and a nod to ECM with the Atlantic energy pitting across east rather than nudging North and squeezing the high away. This could usher in an easterly flow post 23rd Dec.

Like minds 

Not a bad pre Christmas chart from UKMO

https://modeles16.meteociel.fr/modeles/gfs/runs/2021121612/gfsnh-0-144.png?12 

You can see from relatively early in this particular GFS OP that heights are more stout towards Greenland, preventing the Atlantic energy from getting too far North and instead pushing ESE towards Iberia. Very small differences that make a huge difference down the road for our neck of the woods.

Snow across much of southern England by 6pm on the 23rd, according to T+174 on the GFS OP.