Warm winds will brush western coasts driven by a ‘powerful low-pressure complex’ stretching between Canada and Greenland and sweeping warm air between the Atlantic and the Arctic circle.
Wedged against a huge region of high pressure reaching from northern Europe into Siberia, this has created a wind corridor of warm air currents.
It is part of a strong ‘air mass transport event’ which is pushing temperatures in the Arctic around 30C higher than normal.
Severe Weather Europe’s Andrej Flis said: “Strong pressure systems in the sub-polar regions are creating a “wind tunnel” from the North Atlantic into the Polar Circle.
“A powerful low-pressure complex over the Canadian Arctic Archipelago and Greenland is contrasting against a very large high-pressure zone expanding from northern Europe into Siberia.
“We can see a large area of unusually warm temperatures inside the Arctic.
“This is the air transported on a massive scale mostly from North Atlantic.”
The unusual event has gathered strength just as forecasters predict temperatures to rise across the UK.
Thermometers through the coming days are expected to nudge the 20C mark, little more than a week after easterly winds pushed the mercury to zero.
Britain is getting ready for the hottest spell if the year so far, with predictions for warm weather to hold out through March.
The best of the weather will be across western regions next week as spring gets ready to ‘bounce back’.
John Hammond, meteorologist for weathertrending, said: “Thanks to a warming Continent, the chill will be much more muted now, although a brief sleety flurry can’t be ruled out on the highest ground of central Britain on Sunday night.
“The chill will linger near exposed coasts, but as the easterly fades, and under strong sunshine, the air will steadily warm out through the week.
“West looks best for both blue sky and temperatures, and with high pressure still dominant, it’s a mostly dry theme across the whole of the country for several days to come.
“Spring bounces back.”
Blue skies and sunshine driven by high pressure are forecast to hold out through the rest of the month.
However, chilly easterly winds threaten to barge through at times lowering temperatures, they warn.
James Madden, forecaster for Exacta Weather, said: “The sunny conditions show signs of holding out through the rest of March.
“However, there will be a chance of some lower temperatures during this period.
“Temperatures will remain around the mid-teens or just above at best in the southern half of the country.
“There will also be some occasional showers at times in particular in the north.”
Clear overnight skies will bring the risk of chilly evenings and mornings with the risk of frost, he added.
He said: “The more settled weather for the remainder of this month will also induce clearer skies in the evenings.
“This will allow some quite widespread frosts to form and there could be dense fog at times.”
Bookmakers, however, are slashing the odds on this month smashing hot weather records.
Coral is offering 4-5 from 2-1 on temperatures hitting 20C or above at some point in the next week.
Spokesman John Hill said: “We look set for some glorious weather next week. Our betting says temperatures are likely to soar into the early 20Cs.”
Ladbrokes is offering 6-4 from 3-2 on this month turning out to be the hottest March on record.
Spokesman Alex Apati said: “Sizzling temperatures are in store for Brits over the next couple of weeks, and it now looks as though this month could break records as a result.”
Spring is about to bloom, forecasters say, with temperatures set to lift above average for the time of year.
British Weather Services meteorologist Jim Dale said: “We could see highs of 16C, 17C or even 20C in parts this week.
“It will definitely be the warmest spell of weather so far this year.”