The Met Office has issued yellow warnings for “heavy snow” in parts of northern England and most of Scotland. People in northern and central Scotland could face “significant” disruption if travelling between 4am on Thursday and 9am on Friday.
Meanwhile, northern England’s weather warning covers north of Lancaster, west of Newcastle and areas up to the Scottish border. It is in place until 3pm today.
Other regions of the UK face flooding, leading the Met Office to issue a yellow warning for heavy rain. Most of Northern Ireland and swathes of north-west England will be hit with between 20 and 30mm of rain from Wednesday evening.
Northern Ireland’s warning will expire at 9am on Thursday, while the one for Liverpool, Manchester, Stoke and Preston will remain in place the whole day.
The Environment Agency had also issued 10 flood alerts for Wales, and North Wales Police warned that there was heavy rain in the country’s northeast.
In contrast to these wintry conditions, parts of southern England and Wales are set to see balmy temperatures of up to 14C as warmer air moves in from the Atlantic.
Tom Morgan, a Met Office forecaster, said: "More milder conditions are set to move in from the Atlantic on Wednesday evening and will lead to a sort of battleground with the cold air in the north.
"This will cause some of the rain and snow which will impact areas across northern England and Scotland.
"Northern Ireland will see around 30mm of rainfall, while parts of north-west England could experience flooding, as the ground is already very saturated and the rivers are higher than usual".