Cars in snow
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Forecasters say the cold weather is going to kick off on Thursday

An "Arctic plunge" is set to trigger freezing temperatures this week and could bring snow across much of Britain by Friday.

Severe gales are expected to sweep in from the North and cause blizzards on high ground.

This could be only the start of a particularly bad winter with below-­average temperatures and heavy snow for three months, warn forecasters. They say the blast of cold air could see the mercury dip to -13C (9F) overnight in the North, bringing eight inches of snow with wintry showers as early as tomorrow and heavy snow forecast for Wednesday.

It will feel bitterly cold in the South with night temperatures of -7C.

Jonathan Powell, forecaster for Vantage Weather Services, said: "The North and West will bear the brunt although nowhere will escape the risk of wintry showers," he said. "There is a huge swathe of Arctic air set to flood into the North initially but moving down the country throughout the week. Severe gales are set to trigger blizzards in the North.

"We are at risk of snow, ice and freezing fog hitting parts of the South with eight inches possible over high ground in the North."

Snow on car
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Nick Finnis: Friday looks like being a bitterly cold day, with a risk of snow showers
He said Britain could be in line for a particularly severe winter with the worst of the weather expected at the end of December.

"All the signals are that this winter could be a real shocker," he added. "Especially the end of December and into the New Year, we could see parallels with some of the worst winters in history."

Netweather forecaster Nick Finnis said a blast of very cold air later this week could bring a risk of sub-zero temperatures at night, low temperatures by day, snow and strong to gale force winds.

He said: "Major weather models are indicating a cold front surging south during Thursday, followed by a strong and bitterly cold northerly wind sweeping south across the UK. Friday looks like being a bitterly cold day, with a risk of snow showers."

Government forecasters are predicting below-average temperatures until April.

Motorway in snow
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DISRUPTION: Snow is on its way to Britain

The Met Office's three-month contingency plan states: "Indications are that December will most likely be colder than average. For December-January-February as a whole uncertainty is quite large but below-average temperatures are more likely than above-average."

The average temperature for December is 3.9C with 3.6C for January and 3.7C for February.

Met Office forecaster Helen Roberts said: "The cold weather is going to kick off on Thursday. Rain will be followed by snow showers. The North and North-east will bear the brunt of it but there could be snow showers popping up pretty much everywhere."

Leon Brown, forecaster for The Weather Channel, said: "There is a hint of a colder Arctic plunge. There are some extreme model forecasts with snow showers over northern Scotland and along eastern and western coasts."

Ladbrokes is offering odds of 50/1 that temperatures will dip lower than -25.2C this month, beating the December record set in 1981 in Shropshire.

Forecasts of the cold snap come days after official figures revealed there were 31,100 excess deaths last winter. Most of these were among elderly and vulnerable ­people triggered by cold and icy conditions.

wind and snow
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North will be hit by gale winds