Maybe Steve, but a bullish UKMO run and an improved Met update gives me hope.

CMC looks good for a cold Christmas period.

It’s like playing Snakes & Ladders and always landing on a snake….

ECM at T192 is looking quite promising.

Indeed. Looks a bit more promising than the 00z this morning, thus far anyway.

It’s a gnats whisker away from being an absolute stonker. 
More runs needed 😎

The influence of surface colder air is of interest when the fetch is even slightly continental. The GEM in the v. short term: 

At T+ 27 (ie 3pm Thursday) with 850s at 11 -12C over N Devon in a SE wind, forecast max temps are only 9C.

An interesting illustration of how, under these HP conditions, the surface can be several degrees colder than the upper (1500m) temps. 

Worth noting going forward if the air is dry and 850s don't seem to be as low as we might want them.

Yes, as it stands I’d guess transitory snow for some but quite a lot from the Midlands northwards and blizzards from the Pennines northwards.  From an IMBY perspective I’d like a correction south of 250 miles, ie putting those lows in the Channel.  But it’ll probably correct northwards instead….

MOGREPS 12z are mostly cold still on 23/12 but there are some milder runs in the mix.

https://www.theweatheroutlook.com/twodata/mogreps.aspx?run=latest&pschartname=mslp&pscharthour=198

I'd take that!! 

Remember the great easterly let down of December 2012 when the Holy Grail turned to Holy Fail at T minus 96hrs

Point taken. However, I think the output from all models needs to be treated with a considerable amount of caution in these situations.

I still remember the amount of variance there was in the op runs in mid-late February 2018 during the ten or so days before the arrival of the Beast. Some people then were pretty adamant that the atlantic would win, even when support for the easterly began to become more common across the output. February 2005 was another memorable occasion when the models suggested a cold easterly and then renaged, only to then bring the easterly back.

Which model would you trust?

One would hope that it, like all the models, will have been improved quite a bit over the last 9 years. Which still doesn't mean that it will always be right of course. In fact at 10 days range it's likely to be 50-50 at best regarding the overall picture, and less than that in the fine detail.

For some posters in MO it is always the one which is currently conforming to their personal agenda.

Some forecasters are tools... and its a problem also when the forecasters are models. 

We are so damaged by these failures we end up remembering the dates and all. Who’d be a weather enthusiast 

The easterly earlier this year featured a major wobble from GFS in particular and at not a particularly long range either. IIRC I'd taken a day or two away from the models and came back to find a lot of downbeat posts along with the usual 'I told you so' posts, only for the models to drift back to a colder solution. (Fairly sure ECM still had enough cold options to suggest it wasn't a done deal but could be wrong on that). 

TBH I'm far from convinced by a cold spell at the moment but it is objectively (looking at the various ens sets) a strong possibility - we need a few days of consistency and strengthening of the colder signal before I'll be more than a vaguely interested though

Huge huge uncertainty.

https://www.ecmwf.int/en/forecasts/charts/web/classical_meteogram?facets=undefined&time=2021121512,0,2021121512&epsgram=classical_10d&lat=51.57&lon=-0.83&station_name=Reading,%20United%20Kingdom