Last runs of GFS from 18Z were aggressively cold not only continental Europe /https://mkweather.com/2021/01/13/the-most-extreme-outputs-minimum-35celsius-and-maximum-20celsius-in-central-europe//, but too for British Islands and Benelux.
Above parts of British Islands and Benelux should according to these outputs move extremely cold Siberian air -12/-13°C in 850 hPa with results of -20°C frosts possibility (again it is needed to subtract up to 10°C from values on wetternentrale.de maps for absolute national TOPs).
For now, widespread snowfall has appeared in both regions since the start of January 2021 /https://mkweather.com/2021/01/10/the-uk-and-ireland-siberian-winter-will-come-back-last-nights-regionally-coldest-since-legendary-2010/; https://mkweather.com/2021/01/07/the-uk-122c-next-2-nights-will-be-critical/; https://mkweather.com/2021/01/11/france-280c-1042-masl-and-262c-840-masl-germany-223c-810-masl-extreme// and frosts up to -12,2°C have been measured in Scotland, -11,1°C in England and up to -28,0°C in borders of France with Switzerland.
In the Spain, -34,1°C was measured in mountainous regions within AEMET stations and -35,8°C in other mountainous stations and -29,9°C in lower situated basins and valleys after historic snowstorm/https://mkweather.com/2021/01/07/siberian-winter-in-the-spain-341c-new-national-temperature-record/; https://mkweather.com/2021/01/09/madrid-50cm-of-snow-aemet-confirmed-the-worst-snowfall-since-1971/; https://mkweather.com/2021/01/12/30c-frosts-bother-lower-situated-parts-of-the-spain//.
Now, western Europe expect warm period, while extreme frosts in central parts of the continent, Balkan, Scandinavia and Eastern Europe are forecasted /https://mkweather.com/2021/01/13/the-most-extreme-outputs-minimum-35celsius-and-maximum-20celsius-in-central-europe/; https://mkweather.com/2021/01/13/snow-calamity-in-parts-of-europe-still-very-possible-the-worst-it-will-be-in-these-regions-blizzard/; https://mkweather.com/2021/01/12/siberian-winter-until-the-half-of-february-early-spring-conditions-are-shifting//.
In late January, however, possibility of historic frosts will return into northwestern Europe thanks to persisting NAO- phase, although Spain should be already warmer, with stronger Azores high such during the first peak of Siberian winter.
We will see, if extreme times for British Islands and Benelux will be confirming, Mkweather will bring fresh news about next cold outputs for region in articles during next days.