A red weather warning has been issued for parts of Wales tomorrow.
There may be up to 30cm of snow in affected areas, including the Heads of the Valleys and Brecon Beacons, but snow is expected to spread across most of Wales.
The Met office said: "A band of snow, heavy in places, will spread northeastwards across Wales and the southwestern half of England, during Friday morning, lasting through the afternoon and evening across much of Wales, the Midlands, southern and parts of southeast England.
"Winds will strengthen, leading to drifting of lying snow."
A red warning from the Met Office means "take action" to stay safe from the impacts of the weather.
They are advising the public to avoid all non-essential journeys.
There will be less severe conditions over the weekend but further outbreaks of rain, sleet and snow are possible in places.
Andy Page, Met Office Chief Forecaster, said: "The snow is expected to be heaviest during Friday morning across Wales and the southern half of England."
Darron Burness, head of the AA's severe weather team, advised: "Before heading out, check the Met Office weather alerts and traffic reports and allow a bit more time for your journey, as you don't want to rush on potentially icy roads.
"Do the basic checks on your car and, in case of any problems, carry plenty of warm clothing, blankets, de-icer and scraper, some food, hot flask and a fully-charged mobile."
Steve Crosthwaite, head of the Highways Agency's National Traffic Operations Centre said traffic officers "are working round the clock" to monitor the network, deal with any incidents and keep traffic moving.
The Met Office warns that the snow that has fallen will be slow to melt and ice will continue to be a risk, particularly at night.
BBC meteorologist Derek Brockway said on Twitter today: "A RED warning of HEAVY SNOW has been issued for tomorrow. Heads of the Valleys & Brecon Beacons. Red means TAKE ACTION."
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