Temperatures will nosedive through the festive period as freezing air from the North Pole spills across the UK bringing the potential for widespread snow by the weekend.
Parts of the country are now odds on to see a Christmas Day flurry while others will wake to harsh, sparkling frosts as the mercury plunges.
Windchill charts show bitter gales making it feel close to -14C in parts of Scotland in the run up to the big day while further south ‘feels-like’ temperatures will dip to freezing.
Exacta Weather’s James Madden said: “From Christmas Eve and through the weekend it is going to turn colder and more wintry for many parts of the country.
“Snow showers will start to develop on Thursday, and these could become more widespread as we head into the Christmas weekend and snow pushes southwards across the country.
“The best chance of an official white Christmas will be to northern and eastern coastal regions of the UK, and potentially in the southeast.
“Wintery conditions will continue through much of next week and will pave the way for what is looking like a cold and wintry January.”
Bookmakers have slashed the odds for festive snow with Coral now offering 1-2 on a white Christmas.
Spokesman John Hill said: “As we get closer to the big day, there is still a strong prospect of the UK having a White Christmas, although our betting suggests it is Edinburgh and Newcastle which are the most likely major UK cities to see snow on the big day
“London is unlikely to have a White Christmas, however, it has been an unpredictable year, and there may just be one more surprise left in 2020.”
It comes as the emergence of weather patterns similar to those which crippled the nation three years ago prompt forecasters to sound alarm bells.
A stratospheric warming event is expected to set in over the North Pole through the coming weeks causing the Polar vortex–a giant airmass circling the North Pole at -80C–to collapse thrusting Arctic winds and torrents of snow into Britain.
Andrej Flis, spokesman for Severe Weather Europe, said: “A warming event high up in the stratosphere is looking likely to unfold at the start of 2021.
“Stratospheric warming events in winter are very important as they can change the course of winter weather development and affect global circulation.
“A collapsed vortex always greatly increases the chances for winter weather towards Europe and the Continental United States.
“[The Polar vortex] is very cold in its core, with temperatures reaching below -80C.”
Sudden Stratospheric Warming events (SSW) are driven by disruption to wind patterns high above the atmosphere and increase the risk of cold winter weather in the UK.
The phenomenon was the driver for extreme cold and wintry weather responsible for the infamous ‘Beast from the East’ which struck at the end of winter 2018.
John Hammond, meteorologist for Weathertrending.com, warned cold northerly winds will sweep Britain from Christmas Eve bringing snow to parts.
He said: “There is a consensus that, by Christmas Eve, much colder northerlies will be driving down through the UK.
“While this blustery Arctic wind will bring some clearer skies, it may also carry wintry showers.
“For many, Christmas Day will bright and crisp, but a light covering of snow is possible over some of the hills and mountains of northern Britain in particular.”
Temperatures may briefly lift towards the New Year although the next cold blast will follow close behind, he said.
Signs of a Polar Vortex weakening point towards colder weather holding out through the start of next year, he added.
He said: “There’s a very real chance that colder air, lurking to our east, will re-assert its hold over us…as we head towards 2021.
“There are also indications that, at the top of the atmosphere, the stratospheric Polar Vortex will weaken significantly over the coming weeks.
“The upshot of both would suggest to me that our normal dominance of mild westerly winds will be hindered for some considerable time.
“I’d certainly be reluctant to write off the chances that, overall, this winter will end up being colder than normal.”
A spokesman for The Weather Company (IBM) added: “There is still a lot of uncertainty, but the key takeaway is that it looks to become cooler next week with areas of low pressure nearby bringing showers or at times bands of precipitation across the country.
“This will be a mix of rain, sleet and snow with most snow falling around 150m and above.
“On occasion snow will come down to lower levels bringing several centimetres to even lower levels.
“It looks like colder than average temperatures will continue into early January too.”