Blizzard conditions are expected to cause travel disruption for much of Scotland overnight and into the rush hour, forecasters have warned.
Northern parts of the country and the central belt will be worst hit, with amber "be prepared" snow warnings and yellow "be aware" high wind warnings issued by the Met Office for Strathclyde, the Highlands and the Western Isles.
Up to 20cm of snow could fall in some areas, particularly on higher ground. Amber snow warnings are also in place for Grampian, Tayside, Fife, the Lothians and Borders, and both south-west and central Scotland.
The Met Office said gusts exceeding 70mph could hit Orkney and Shetland, with conditions on the mountains described as "atrocious". Gusts reaching up to 60mph are also expected in Grampian.
The westerly gale-fore winds mixed with frequent and heavy show will create temporary blizzard conditions, it said.
Gareth Harvey, a forecaster with MeteoGroup, the weather division of the Press Association, said: "There will be heavy showers of snow and sleet right down to lower levels throughout the course of the night and into the morning, and it will be blustery. There will be 10-15cm accumulations over the mountains and 2-5cm on the lowest ground potentially.
"There are some suggestions the western half of the country will be more affected by the showers than the east. The snow will be drifting around in these strong winds, adding to the problems. Exposed western coastal areas will see gusts of up to 60-65mph and as you come in land that will probably be more like 35-45mph."
Mr Harvey added: "The trend is for the cold air to stay with us."
The Met Office said the wintry showers will fall largely as sleet and hail along coasts, turning to snow as they move inland, and exposed western coasts are likely to be affected by unusually high sea levels and swell conditions.
Ice will also create an additional hazard. The Met Office warnings are in place until 9am, with the forecaster saying: "The public should be prepared for possible disruption, especially to travel."