Blizzard conditions are set to hit the Westcountry bringing warnings of major disruption on the roads.
Up to four inches of snow is predicted to blanket Devon on Friday, with Dartmoor, Exmoor and other upland areas worst affected.
More than an inch (30mm) of rain was expected to fall in Cornwall during a 12-hour period from midnight - one fifth of the average rainfall in the whole of January.
Gale-force winds of up to 45mph are predicted to combine with the rain and snow- bringing travel misery throughout the South West.
Freezing temperatures will exacerbate the situation in the region, with forecasters warning icy conditions will bring more trouble over the weekend.
The Exeter-based Met Office has issued an amber weather warning telling people to "be prepared" for snow on Friday. It also issued a yellow warning telling people to "be aware" of snow on Saturday.
Met Office forecaster Charlie Powell predicted many parts of Devon would wake-up to snow.
"There is something of a battleground in terms of the weather. Cold air is creating a barrier against the latest front coming off the Atlantic," he said.
"The blizzard conditions could cause disruption to commuters with the mix of rain, sleet and snow.
"Driving conditions could be difficult in Devon even on the main commuter routes such as the M5, A30, the A38 and A380 around Haldon Hill and Telegraph Hill.
"Although most of the snow will be gone by midday, some snow will lay on Dartmoor and Exmoor. Icy conditions will linger around on Saturday and Sunday."
Drivers were warned to stay off the roads unless their journey is absolutely necessary.
Steve Crosthwaite, head of the Highways Agency's National Traffic Operations Centre said: "We advise drivers to check road conditions and the Met Office weather forecast before they set off and during severe weather to consider whether their journey is essential.
"They may want to delay their travel until conditions improve and to allow our winter fleet the chance to treat the roads."
Drier conditions will remain in place over the weekend before a band of rain arrives overnight on Sunday, bringing a spell of unsettled cold weather and the possibility of hill snow next week.
Hundreds of motorists were trapped in snow on Haldon Hill for up to eight hours in 2009 and 2010.