The latest offering from the GFS model predicts a rather cold northwesterly airstream on Christmas Day, a bright looking day with wintry shower especially across northwestern areas. This brief cold snap may well be the last in a series of cold north or northwesterly incursions that you can trace back to the end of October (fig 1).
As so often happens between Christmas and New Year, the weather drastically changes in mood, and this year doesn’t fail to disappoint in this regard, as it turns progressively milder on Boxing Day, and by the start of 2018 its super mild across the British Isles and the bulk of Europe, if this chart for January 1st is to be believed (fig 2).
The GFS solution does contradict the latest extended outlook from the Met Office though, which suggests that in the final days of December “Temperatures will be near to or below average and snow is likely, at times”, they go on to imply that things might turn more settled and anticyclonic as we go into January 2018 (fig 3). As always, it will be interesting to see what transpires in a couple of weeks time.