"By Thursday it is likely that it will be become exceptionally cold and day time temperatures may hover just around freezing or even below freezing in some places with widespread severe frost at night".
The last "sudden stratospheric warming" was present in 2010 which brought the coldest December on record for most parts of Ireland with low temperatures of minus 17.5 degrees in places. More snow is expected throughout the day, especially on higher ground. There is a risk of some snow next week as the cold air picks up moisture over the North Sea.
The Met Office also said there could be some frosty nights, and warned that into next week even colder air from Russian Federation could move across the country.
In a statement on the Met Office website, the warning advises: "Snow showers may become persistent from late Monday afternoon, continuing overnight and throughout Tuesday".
Brent Walker, Met Office Deputy Chief Meteorologist, said: "There is potential for this cold spell to be the coldest for several years in the south".
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The freezing winds are forecast to sweep in from Scandinavia due to the influence of a high pressure zone.
"It will feel much colder with a wind chill of -1 to -8C for Britain, -8 to -14C for central Europe but -15 to locally -30C for north-east and eastern Europe". However it will remain cold, with a strengthening southeasterly breeze. Maximum Temperature 5 °C.
"Saturday night will be dry with good clear spells and easterly winds will be light to moderate".
Thermometers will fall as low as -4C in parts of Scotland and England by Sunday, as forecasters warn of up to 10cm of snowfall in the coming days. Further snow showers follow Monday and Tuesday, perhaps heavy at times.