Temperatures could rise as high as 14C (57F) in parts of the UK on Monday, the Met Office has predicted, but the warmer weather will bring a risk of flooding.
Most of south Wales, the south-west of England and some of the south-east is under a yellow warning for rain, with a chance of some flooding. Surface-level flooding may also occur in other parts of the UK as snow and ice on higher ground melt overnight.
An amber warning for ice was in place for the north of England on Sunday evening, with frozen rain and snow making travel conditions hazardous.
In the amber warning area, which covers most of Yorkshire, the north-east and the north-west, freezing rain could lead to the build up of 2-3mm of ice on untreated surfaces, the Met Office said, which could cause treacherous travel conditions and road closures.
“Obviously, we’ve had some very cold air coming down from the north and the Arctic for a week, 10 days or so, but now we’re starting to see the Atlantic air coming back in from the south-west,” said Marco Petagna, a Met Office meteorologist.
“We’re set to see a big change into much milder weather [on Sunday], when we’re looking at temperatures in double figures.”
Sunday was a “transition day”, he said, with the amber warning in the north of England in place until midnight, and warming temperatures expected to begin to thaw snow and ice overnight.
The west coast of Wales was predicted to have the warmest weather on Monday, reaching as high as 14C.
It is unusual to have a change in temperature from several degrees celsius below average to several degrees above, said Petagna.
“Temperatures climbing overnight is an unusual feature. Obviously, in the winter, we’d normally see temperatures dropping overnight, but with the milder air coming in, temperatures will climb.”
However, the warm weather is unlikely to last until Christmas Day, the Met Office said.
Petagna added: “At the end of the week, there is a hint that we could get some cold weather coming back down from the north, but there’s a lot of uncertainty about how far down south it will spread and how cold it will be. It’s a long way off and plenty can happen in the meantime.”
