Weather forecasters have identified the exact moment an Icelandic freeze will grip the UK.
Maps and charts suggest the country is due another cold spell over the next week, with temperatures likely to descend back into the minus range ahead of Christmas.
Snow and freezing rain are on the cards for thousands of Britons, especially those living in the north.
Meteorologists have predicted that Scotland will bear the brunt of the coming cold spell as it slides south from the Arctic Circle.
One forecaster has warned Britons could see the “whites of the Arctic’s eyes” until New Year’s Day this year.
Speaking to Express.co.uk, Jim Dale, the chief meteorologist and founder of British Weather Services, said Scotland would likely see snow in time for Christmas.
The forecaster said that while the coming cold system will position itself over the home nation, “most other places” will also get a taste of the chilly weather.
He said: “I think Scotland is in the main frame for Christmas snow but it could well be the run into New Year’s Day that we see the ‘whites of the Arctic’s eyes’ for most other places.”
Maps from WXCharts looking at weather patterns high in the atmosphere back up the meteorologists’s predictions, showing a column of cold air descending from the north next week.
Charts from the service, which uses data from MetDesk, show conditions 1,500 metres into the atmosphere, where cold fronts develop.
The 850hPa temperature maps suggest that Iceland’s colder atmosphere will drift south with the first snow arriving in the north of Britain from December 21.
Atmospheric temperatures of -5C translate to still mild lows of 5C on land, and these will gradually drop as the cold weather continues to move.
By December 25, the cold atmosphere appears likely to settle in a strip across northern England and Scotland, driving surface temperatures to a minimum of -2C north of the border and 5C further south.
The forecast is still distant, however, and subject to change over the next 10 days, with the Met Office currently reluctant to issue a concrete Christmas Day forecast.
The weather in the run-up to December 25, the agency states, will likely be “largely dry and increasingly mild” thanks to the jet stream’s southward shift.