Britain is braced for the first significant snowfall of winter, with an overnight flurry expected to cause early morning disruption.
Up to 20cm (7.8in) of the white stuff is forecast to fall on higher ground in northern England, potentially leaving difficult driving conditions in its wake.
The first flakes were expected to hit Scotland this afternoon, before moving south to the Pennines.
A yellow Be Aware warning is in place for much of the west of Scotland, the north-eastern tip of Wales, parts of the North West and North East of England, and down into the Midlands.
Temperatures will be around -1C to freezing overnight, up from a low of -6.6C last night, but intense rainfall is likely to turn to snow when it meets the cold air, meteorologist Emma Sharples said.
She said: "The snow overnight is likely to be still on the ground come rush hour in the morning, so people need to be aware of that and perhaps allow for some disruption to their travel plans."
She added: "We could well have some slushy deposits around and it may take until the afternoon until we can clear that."
Leeds and Sheffield could have up to 20cm (7.8in) of snowfall, but lower lying parts of Yorkshire and into Cheshire could see around 10cm (3.9in) of snow settling overnight, the Met Office said.
The weather warning is in place until 10am on Wednesday.