England and Wales have been warned to expect the heaviest snow of the winter so far, with a chance of up to 10cm (4in) falling in some places.
The Met Office put the whole of England and Wales on alert to expect snow on Tuesday and ice on Wednesday.
Some areas may escape the snow, but a covering of 2cm is expected in most areas on Tuesday evening and on higher ground there could be up to 10cm. By Wednesday temperatures will plummet under clear skies, leading to widespread frost and icy roads.
There was also a separate warning for ice in north-east Scotland on Monday.
The Met Office warned of possible disruption including delays on roads, stranded vehicles and rail and air travel cancellations.
It said there was a slight chance that rural communities could be cut off and power cuts may occur.
Met Office spokesman Grahame Madge said: “We would urge people to allow longer for their journeys and perhaps to question whether their journey is necessary.
“It is fair say that this is likely to be the heaviest snow of the winter so far for large parts of England and Wales. We have warnings in force for the whole of England and Wales for snow and ice.”
Madge added: “Some places will encounter rain but as it moves eastwards and bumps into the colder air it could well turn into snow. We are looking at 1 to 3cm on a fairly widespread basis. That may be more on some of the higher ground. Perhaps the Pennines, Peak District, parts of Wales, Dartmoor to get more than that, possibly up to around 10cm.
“Then we’ve got the risk of ice forming after that, because as that front moves through it will be bring colder air behind it. The commute on Wednesday could well be challenging.”
Public Health England urged the public to keep an eye on those most vulnerable to the cold. Dr Emer O’Connell, one of its consultants, said: “Now is the time to prepare and look out for those most at-risk of falling ill. If you can, check on family, friends and neighbours who are older, have heart and lung conditions or young children as all these groups are particularly vulnerable to the effects of cold.”
Network Rail Scotland said it had teams on standby to “respond to any issues which may arise”.
The warnings follow a windy weekend that left parts of Wales and the West Country without electricity on Sunday as overhead cables were felled. Western Power Distribution said about 1,000 properties could have been affected by the weather over the weekend.
Strong northerly winds with gusts of up to 70mph pounded the west and east coasts. The Met Office said the winds would slowly ease overnight into Monday.