Thought it'd probably be worth posting the London GFS ens, which show it being mainly on the chilly side of average over the next 9-10 days, just in case any other comments confused the matter.
Post 26th a good possibility we'll experience some much milder weather down here, with temps hitting 10-11c on the corresponding T2M plots, probably for 24-48 hours although could be a touch longer I guess. Slim chance though it stays colder and temps struggle to average at best.
Longer term and there's the expected plenty of scatter but a reasonable chunk of said scatter is on the colder side of average, suggesting there will be an ongoing chance of cold weather re-establishing in the south into February.
Taking the ens further North shows a similar picture albeit more chance of snow throughout and temps more likely to remain a touch lower than average throughout, particularly for Scotland.
Just looking at the GFS Op and as you'd expect given the setup, Wales North shows the most likely position of any snow, with snowfall shown from mid afternoon Wednesday for parts of Scotland, more widely in Northern England and again parts of Scotland during Thursday along with parts of Wales and a wintry shower risk continuing through in to Sunday with a band of mostly snow moving down through the Midlands. Thereafter Tuesday 26th Jan shows a band of rain turning readily to snow at least for a time from the Midlands North and a similar repeat occurrence on Thursday 28th, Scotland tending to remain on the snow side (at least for higher ground and away from some of the coastal fringes) throughout. No it won't verify exactly like that but that shows snow chances for over a week and not just restricted to Scottish mountains or the highest ground of Northern England.
ECM shows a broadly similar picture. The Op was towards the top of the milder options around the 25th Jan so may be being a little too enthusiastic with the HP build to the south at that time and consequently the extent of the milder air dragged towards the South. It's not an outlier though so some support for that evolution.
TBH if you'd stripped out the colder ens, particularly when they became the minority option last week you'd have said the pattern would have looked very similar to the London end up to the 26th of Jan, with the uncertainty post that period greater. So other than firming up on a possible couple of day window for quite mild weather down here 27th Jan (ish) the consistency in the models hasn't been too bad IMO. Certainly what's being shown as likely now was what I thought was likely from the middle part of last week
No it's not a prolonged deep cold spell and yes the south is likely to see mostly cold rain but it's not a mild pattern for the most part and snow chances are there for quite a few areas for quite a bit of the time. It also wouldn't surprise me if some of the Midlands saw at least temporary snow and other places in the south a few flakes. Not great of course but it is what it is and consistent with what's been shown by the ens for a while now.
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