The Army is on standby to deal with weather-related emergencies over the next few days as Britain braces for the most severe whiteout since 2010.
Up to eight inches of snow is forecast in parts of the north while up to two inches could fall anywhere across the country.
The Government has issued a raft of weather and health warnings from tomorrow when the first of the snow is expected to fall.
Thermometers will nosedive to -10C overnight in the north while most of the country will struggle to get much above freezing in the run up to the weekend.
Severe weather warnings for wind and snow are in place across Scotland, northern England and the coasts until Friday.
Spokesman Grahame Madge said heavy rain due to lash southern regions on Thursday could turn to snow as temperatures plunge.
He said: “Rainfall over southern counties on Thursday is likely to be heavy and where it bumps into the colder air mass we could see snow.
“There could be disruption for a while as this system moves through.”
Chief forecaster Dan Suri said strong winds, blizzards and lying snow threaten disruption to travel and power supplies.
He said: “Snow showers are expected to develop from Wednesday evening lasting into Thursday. “These, combined with strong winds, could lead to locally very poor travel conditions.
“Wind gusts up to 55 mph are expected in exposed coastal areas and on hills in association with snow showers, leading to temporary blizzard conditions.
“Two to five centimetres of snow could accumulate anywhere within the warning area with 10-20 centimetres possible above 300 metres.
“Lightning may accompany the heaviest showers, with potential disruption to power supplies as a consequence.”
WeatherOnline forecaster Garry Nicholson warned to brace for the mercury to nosedive as air floods in from the Arctic.
He said: “A dramatic drop in temperature will take place by Thursday as cold Arctic air spreads from the northwest.
“Heavy snow and hail showers will affect the west and the north during Thursday and Friday.
“Thunder and lightning is possible locally and bands of snow may spread into central areas at times.
“Some travel disruption is likely.”
Spokesman Rod Dennis said: “The see-saw weather we’ve seen in the last few weeks continues with a switch this week to much colder, and much more unsettled conditions for all of us.
“Even a small amount of snowfall has the potential to cause major disruption for motorists.
“Commuters and those drivers planning longer journeys this week must heed the weather warnings and be prepared for tricky driving conditions and significantly extended journey times.”
Exacta Weather forecaster James Madden said: “The first belt of snow is likely to hit northern and western parts of the country from Wednesday evening and during the early hours of Thursday.
“This could be the start of prolonged cold and widespread wintry weather.”
Experts have urged people to watch out for elderly friends and relatives amid fears people could die in extreme cold weather.
More than 24,000 people died last year while 15 per cent more deaths were recorded during winter compared to the rest of the year, according to the Office for National Statistics (ONS).
Malcolm Booth, chief executive of the National Federation of Occupational Pensioners (NFOP) said: “Be extra careful when going out as pavements may not have been treated.
“Check on neighbours and relatives regularly and keep warm and well fed.”
The Ministry of Defence said troops are ready to support communities hit by bad weather in the coming days.
A spokesman said: “Our Armed Forces are committed and professional and are ready should they be needed to support local authorities in responding to adverse weather in our communities.”