Up to 20cm (8in) of snow could fall this weekend as forecasters warn of a mini “Beast from the East”.
Sky News meteorologist Chris England said on Thursday that it would turn “much colder” over the next few days, with a “raw wind from the Baltic bringing widespread snow showers”.
Snow has already started falling in the Grampian mountains in Scotland, he said.
The Met Office says the snow and ice will begin in some places from 3pm this afternoon. The worst of the weather will be across London and the South East and the Midlands and southern Yorkshire – all from around 4pm tomorrow afternoon, and into Sunday morning.
The 20cm (8in) of snow is forecast on higher ground and 5cm (2in) in other areas, which the Met Office said was enough to cause a “fair amount of disruption to transport”.
“Snow showers are expected to become more frequent through Saturday evening and night with icy patches also developing on some untreated roads, pavements and cycle paths,” forecasters say.
They added: “Travel delays on roads are likely, stranding some vehicles and passengers. Some delays and cancellations to rail and air travel are likely.”
Met Office forecaster Craig Snell said the cold snap will only last a few days, and after a high of 15.9C on Thursday, many places in Britain over the weekend will be nearer to freezing.
“As we go through the course of Friday the rain across eastern Scotland and north east England will gradually transition to snow across the higher ground,” he said.
“Then as we go through Friday night and into Saturday, that snow risk then falls down to lower levels and with an increased risk of ice as well.
“Sunday will see a fairly widespread yellow warning for snow across a good chunk of England, and also parts of eastern Wales.
“The other thing to note is that will be quite windy and that will enhance the cold feel.
“If you factor in the strength of the wind it will be feeling probably sub zero, so a big change in how it is going to feel out there over the weekend.”
The low temperatures are likely to continue on Monday but things will starts to warm up from Tuesday.
During the cold snap earlier this month, motorists in two parts of the UK reported getting stuck for 17 or 18 hours as snow and high winds brought treacherous driving conditions.