Broad pattern remains good if you want cold.

Details such as how far north that LP moves, how fast it weakens, what attack angle won't be resolved for a while so the rollercoaster ride will continue for a while yet!

By the way

That is a very strong temperature gradient.

If you want a good frontal snow event, this is the kind of thing you want to be seeing. Weak fronts produce drizzle, strong fronts produce snow even if the temps seem slightly too high on paper.

And roughly the heaviest snow probably corresponds to roughly where the -2C isotherm is.

But since this is so far off this could move north or south so the location isn't really all that important.

ECM delivers a blow at 168. Not a write-off yet though. 

MOGREPS 6z offering solid support for milder conditions in the south. 12z update should be available soon.

That’s probably the coldest ensemble set of the winter from the GFS for this location:

Very snowy xmas day for N England for the ECM

The 0C 850hpa isotherm is the dividing line.

Its easier to see on the 850hpa wind where the front is. Snow to the north of and in the white area.

JMA XMAS Eve

https://www.meteociel.fr/modeles/jma.php?ech=168&mode=1&nh=0

Looks interesting 

There's no doubt that the Greenland High is heading north, and that's bad news for the south over Christmas.But look what it means for the polar vortex. Torn to bits. Plenty of good model watching to come.

Just NE England? 

Wow that is a strong signal - game over for those that live in the South I would say.

Just need that low pressure around the 23rd to sink further south on the ECM!

ECM appears to be the top end of ensemble runs tonight,

https://www.ecmwf.int/en/forecasts/charts/web/classical_meteogram?facets=undefined&time=2021121712,0,2021121712&epsgram=classical_10d&lat=53.2&lon=-2.91667&station_name=Chester,%20United%20Kingdom&altitude=12

As always more runs needed.

Martin

Yes, the ECM 12z ensemble mean is not bad at all. An interesting mean chart for Christmas Day:

Yes, on the current output the dividing line does indeed look to be 200-300 miles further north.   But not only has that line shifted north it's also been brought forward.  That chart shows a cooling trend into Christmas Day.

This is still very far from being resolved.  IMO we could still end up with almost anything, from mild air pushing through the entire country to cold conditions returning.

Anyone south of the midlands will have to wait for a 2nd, 3rd or 4th bite at the cherry going by that 🍒 🥶

[quote=some faraway beach;1400837]

There's no doubt that the Greenland High is heading north, and that's bad news for the south over Christmas.But look what it means for the polar vortex. Torn to bits. Plenty of good model watching to come.

Is this showing a split in the polar vortex??

And thus it is, and has always been.

Although the writing might be on the wall for the south, there could very well be corrections to come. Infact I’d put good money on it.

How ironic would it be if we go full circle and end up with an anticyclonic Christmas as previously and once strongly signalled.  

I note a lot of the rampers have vanished.  The way people abandon the MO thread when there's some bad runs in hunting down a cold spell puts me in mind of the way the Deatheaters vanish in the climax of The Deathly Hallows pt II when old Volders is clearly losing his powers.

Who knows! I suspect tonight’s picture is not the final one for Christmas.

Of that we can agree. The way its currently trending you wouldn't rule out our friend Uncle Barty paying us an unwelcome Christmas visit.  

Exactly q.... its all just speculation by the models at the moment...

Overall outlook looks decent