Snow has fallen across many parts of the UK overnight, with forecasters warning that road, rail and air travel may be disrupted.
The Met Office said “increasingly frequent” snow showers were affecting parts of Scotland, Northern Ireland and northern England.
It said 10-20cm of snow could fall in northern Scotland, Northern Ireland, north-west Midlands and north Wales.
The Met Office has yellow “be aware” warnings in place for snow and ice.
It said across the UK, 2-5cm (1-2in) of snow was likely in the other affected areas.
“The heaviest and most frequent snow showers will progressively become confined to north-east Scotland during Saturday,” it said.
It comes after Storm Caroline brought winds gusting more than 90mph on Thursday, disrupting rail and ferry travel and shutting dozens of schools in Scotland.
About 500 homes remain without power in Scotland as repair teams were stood down for safety reasons overnight.
And passengers had to spend a night on board the Orkney ferry Hamnavoe after it was unable to berth in Stromness.
BBC weather presenter Louise Lear said although the storm-force winds were expected to ease during the night, conditions will remain blustery and there will be a cold start to Friday with temperatures ranging from -2C to 3C (28F-38F).
About 8cm of snow had already fallen in Aviemore, in the Highlands, by dawn on Friday, while parts of Northern Ireland, Wales and areas to the west of the Pennines had also seen a covering.
Pictures of the snow showers have been shared overnight on social media.
Met Office meteorologist John West said: “It will be bitterly cold, with highs of 2C or 3C outside those snow showers. But the wind chill is going to make it feel sub-zero.”
Cold temperatures are likely to remain well into next week, with forecasters also warning that Sunday could see further heavy snow showers.
Another yellow weather warning for snow has been issued for central parts of the UK, which is in place from 04:00 on Sunday until just before midnight.
The Met Office earlier warned that some rural communities could be cut off and said there could be “possible delays and cancellations to rail and air travel”.
It said Storm Caroline’s winds were now confined to the far north-east of mainland Scotland and the Northern Isles, and there could be gusts of 70-80 mph at times, especially over Shetland, on Friday.
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