Britain could be hit by a -10C winter blast bringing more than three inches of snow this week.
A sharp twist in the jet stream is about to open the floodgate to bitter Arctic winds bringing freezing fog and widespread frosts. Sleet and snow is forecast as far south as Wales and the Midlands by the weekend with wintry showers possible across the country.
The chilly outlook comes as Britain reels in the aftermath of devastating Storm Imogen which struck on Monday. Thousands of homes are still without power as torrential rain and winds of up to 100mph lashed swathes of the country.
Colossal 14-metre waves battered coastal regions sparking a raft of flood warnings and alerts while transport networks were thrown into chaos.
Although winds have died down, Britain faces a new twist in the winter weather as bitter winds send thermometers plunging.
Netweather is forecasting overnight temperatures of -10C in Scotland and the north with lows of -2C further south. It threatens further misery for flood-hit regions with saturated ground likely to turn in to lethal sheets of ice.
Experts say the jet stream, which has until now been positioned north steering storms in from the Atlantic, is about to dive southwards.
Leon Brown, forecaster for The Weather Company, said: “The forecast has a changed a bit for later this week with the jet stream a bit further south and hence Atlantic weather systems keeping further south.”
Wednesday will be a bright and chilly day with sunshine and a few showers with some heavier showers across Devon, Cornwall and Scotland.
He said most places will feel the cold by Wednesday with frost, ice and freezing fog a risk towards the end of the week.
A clash between cold and milder air at the weekend could trigger snowfall as far south as Wales and the Midlands, he added.
He said: It will be frosty on Wednesday night and Thursday morning, and also icy with showers over Wales and parts of the Midlands and snow moving south across northern to central Scotland.
There will be widespread frost on Thursday night into Friday morning with freezing fog over central and southern Britain.
This weekend becomes more complex with a potential clash between a cold easterly flow from Scandinavia and milder Atlantic air to the southwest.
An area of low pressure is likely to develop and move across southern Britain with a snow risk across Wales and the Midlands through the day and evening and as much as 2cm to 8cm possible, especially over hills.
On Saturday there is a risk of low pressure running across southern Britain and this would bring a sleet and snow risk across Wales and the Midlands.
The Met Office said things will start to turn colder from Wednesday as cold air spills in from the Arctic.
It said a separate band of milder air arriving by the weekend will lead to snow fall across a few regions by the weekend.
Spokeswoman Lindsay Mears said: There could be some hill snow arriving on Tuesday before it turns much colder for most people through the week.
We are expecting temperatures below freezing in the north by the weekend and daytime highs of around 6C or 8C further south.
On Friday the wind will change again coming from a westerly direction bringing more unsettled weather and as this meets colder air it could bring some snowfall over a few areas of the UK.
James Madden, forecaster for Exacta Weather, said cold weather could hold out through the rest of this month.
He said: The colder and wintry theme will begin to take more of a stronghold into the second week of February as the UK becomes locked in an icy and wintry grip.”
Magical snowy scenes in nothern England