Blizzard conditions are set to sweep in, bringing "a real taste of winter to the whole of the UK".
Frequent snow showers and strong winds are expected widely across Scotland, Northern Ireland, Wales and the north of England on Thursday with the possibility of sleet or snow for a short time in the south of the UK.
Forecasters said it will be much colder for all parts of the country with daytime highs of 2C to 5C but it will feel even colder with gale-force winds.
The Met Office described it as a "real taste of winter" caused by a polar airmass, which originated over northern Canada, spreading south across the UK.
It follows a wet and windy day on Wednesday for Scotland and the north of England that left homes without power and major travel disruption.
A gust of 93mph was recorded at High Bradfield in South Yorkshire and 82mph at Emley Moor in West Yorkshire.
Engineers worked to reconnect thousands of homes in Yorkshire, Cumbria, Cheshire and the north of Scotland and will be on standby throughout Thursday.
The Forth Road Bridge that connects Edinburgh and Fife was closed all day after a lorry was blown over and damaged the central reservation. The 54-year-old driver was charged by Police Scotland as the bridge was closed to high-sided vehicles at the time of the accident.
Paul Gundersen, chief meteorologist at the Met Office, said the heaviest and most frequent snow showers are likely across northern and western Scotland, Northern Ireland and around Irish Sea coasts, but eastern coasts will also be affected in the coming days.
"Most northern areas are very likely to see snow showers at times over the next few days, but the situation over the southern half of England is more complicated," Mr Gundersen said.
"Southern counties of England and Wales can expect a cold and wet day with some heavy rain on Thursday, but there's an increasing chance this will turn to sleet or snow, especially over hills, during the afternoon and evening.
"There is a chance of snow settling bringing disruption to transport during the evening rush hour and possibly interruptions to power supplies, this more likely across East Anglia and south-east England. As skies clear on Thursday night it is likely to become icy in many areas.
"Forecasting snow is always challenging and there's often a fine line between whether it will rain or snow in a particular location depending on slight changes in air temperature. Keep an eye on the forecast and warnings for your area for the latest information."
The Energy Networks Association has reminded people they can call 105 - the new, free national phone line - if the weather damages their local power network and affects their electricity supply.