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A rare Polar vortex phenomenon could be about to hit Britain for the first time in four years, Government bosses and emergency services are being warned.

The Sudden Stratospheric Warming (SSW) alert is contained in the UK government official February to April forecast being briefed to the Cabinet Office, transport bosses, councils and emergency services, reports the Weather Channel.

The SSW will lead to another icy snap, with lots of clear, dry weather with night-time frosts.

The Big Freeze in December 2010 was triggered by a similar SWW - and the last time Britain was hit by one it caused the coldest March in 51 years in Scotland, with snow and -12.5C lows as late as March 31 in Braemar, Aberdeenshire.

The North Pole phenomenon may spark a new Arctic blast because high-altitude air has suddenly warmed up and is set to shunt cold low-level air south towards Britain.

The February to April contingency ​outlook said: “The probability of Sudden Stratospheric Warming is higher-than-normal in February.

“These events disrupt the stratospheric polar vortex and, more often than not, bring cold weather to the UK.”

Some forecasts claim there is a chance of a sudden stratospheric warming event in the coming weeks, leading to colder weather from the east towards the end of the month.

How will Sudden Stratospheric Warming effect UK?

Forecaster Dr Dave Reynolds, of The Weather Channel , said the mass of Polar air was set to expand and possibly drag bitter air towards the UK.

He explained: “There is a clear indication of an imminent split in the polar vortex, currently located over central-western Greenland.

“The main centre will drift to the Canadian Plains, while a new ​area will form over northern Russia ​.

“This will drift towards the Caspian Sea, then westwards across the Mediterranean, Iberia and out to the near Atlantic during the next two weeks, weakening as it does so.

“The process of vortex splitting is accompanied by sudden stratospheric warming, whereby temperatures in the stratosphere rise.

“This warming can then extend downwards through the depth of the atmosphere and result in an increased risk of blocking, which in winter-time raises the chance of widespread cold conditions developing.”

This ​prevents milder conditions from the west heading across the Atlantic allowing colder air to dominate. However, there’s no guarantee Europe will see increased cold.

Dr Reynolds added: “To go from vortex splitting and sudden stratospheric warming to a blocked pattern won’t occur overnight, it’s a process that can actually take some 10 days to three weeks.”

The forecaster said computer models indicated a cold, blocked pattern over Scandinavia for the last week of February and first week of March, reinforced by a possible polar vortex split and accompanying stratospheric warming. He said experts were closely monitoring forecasts for more evidence of the imminent phenomenon.

When was last occurrence of Sudden Stratospheric Warming?

The last SSW event occurred four years ago, according to official data, and brought the coldest March for 51 years to Scotland, with snow and -12.5C lows as late as March 31 in Braemar, Aberdeenshire.

SSW events also triggered -16.1C lows in the Scottish ​ Highlands​ during November 2010 - starting the month-long Big Freeze in December 2010.

Today's Met Office Weather forecast: Cloudy today with outbreaks of rain

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Today:

Skies will be on the cloudy side today. It will be dry in the east at first, but outbreaks of rain will gradually work their way eastwards through the day. Milder than recently. Maximum temperature 10 °C.

Tonight:

Some heavier bursts of rain will move across the region through the first part of the night. Rain should clear by the early hours with some wintry showers pushing in. Minimum temperature 1 °C.

Friday:

Friday will be largely dry, bright and cold across the region with brisk winds in the west. A few sleet and snow showers are possible, mainly across Devon and Cornwall. Maximum temperature 7 °C.

Outlook for Saturday to Monday:

Turning wet and windy on Saturday with some hill snow. Sunshine and blustery wintry showers returning on Sunday. A few wintry showers still on Monday, but plenty of bright spells.