Large parts of Scotland are braced for snow while heavy rain and strong winds lash much of the rest of the UK.
Heavy and persistent snow is forecast north of the border on Thursday morning, with 2cm to 5cm likely for many parts and up to 20cm on the highest ground, the Met Office said.
A yellow "be aware" weather warning for snow kicked in just after midnight for the Scottish Highlands, Western Isles, Grampian, Strathclyde and Central, Tayside and Fife regions.
The warning, which covers the morning rush hour and is valid until 1pm on Thursday, warns that some roads and railways are likely to be affected, with possible longer journey times for road, bus and train services.
Meanwhile a yellow weather warning of heavy rain was in force for southern Scotland, northern England and Wales until 9am on Thursday.
Forecasters warn that spray and flooding on roads will make journey times longer while bus and train services are also likely to be affected.
Strong winds were also forecast south of the border for the early hours of Thursday.
Met Office spokeswoman Nicola Maxey said: "Snow is forecast for northern Scotland and this could potentially affect travel in the area.
"Outside that area snow is not going to be an issue, it's more likely to be heavy rain."
In the Highlands rail passengers faced disruption after three landslips following heavy rain forced the cancellation of some services.
Train services from Inverness to Kyle of Lochalsh and Wick were affected, with the line blocked between the Highland capital and Beauly.
The Scottish Environment Protection Agency (Sepa) has issued flood alerts for Dumfries and Galloway and the Borders.
Here is your morning rush hour forecast - parts of Scotland will be cold with snow in places. Brighter & milder elsewhere but breezy for all pic.twitter.com/1nvQhh72IB— Met Office (@metoffice) November 22, 2017
South of the border there are a number of flood warnings in force, mostly in north west England, and dozens more flood alerts.
RAC spokesman Pete Williams said: "We are warning drivers across the UK that high winds will make conditions challenging.
"The advice is for drivers to slow down and ensure they double the normal recommended two-second distance between their car and the vehicle in front.
"Hold the steering wheel firmly and be prepared to be buffeted by gusts of wind.
"Drivers in Scotland who travel on roads on high ground and mountain passes should be prepared for snowy conditions.
"It's wise to pack a 'winter survival kit' including a shovel, blanket, additional warm clothing, a torch, a flask with a warm drink and ensure your mobile phone is fully charged and consider letting your friends, family or colleagues know when you expect to arrive.
"It may be worth delaying your journey or taking an alternative route until conditions improve and the snow ploughs have made roads fully passable. Keep tuned to the weather and travel forecasts on local radio."