The Met Office is warning of the risk of disruption as heavy snow is forecast across many parts of the UK on Friday.
A band of rain will push into the west into Friday morning, turning increasingly to sleet and snow. Wales is particularly at risk of seeing significant falls of snow and the risk of blizzard conditions in the strong winds.
An amber warning is in place for parts of Wales, including Caerphilly County Borough, where accumulations of 10 to 15 cm are expected and 20 cm or more over the hills.
The warning means people need to be prepared for the weather and take steps to change plans.
Eddy Carroll, Met Office Chief Forecaster, said: “The snow is expected to be heaviest through Friday morning, slowly weakening and clearing east during the second half of the day.
“Clearly there is the potential for significant disruption to peoples plans. We should all keep up to date with the latest weather forecasts, advice from local agencies and be prepared to change our travel plans if necessary.”
Darron Burness, head of the AA’s severe weather team, said: “With the outlook remaining cold, drivers need to be prepared for possible disruption.
“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.”