Freezing temperatures which have disrupted Scotland’s roads this week are set to continue, forecasters have warned.
The UK's Met Office issued its highest red-alert warning for winds of at least 75mph between 3pm and 6pm tomorrow.
A spokesman said travel conditions will be “extremely poor” tomorrow and motorists could face “significant delays”.
Gusts are expected to reach 90mph during afternoon rush hour in the Borders, Strathclyde, Tayside, Fife, the Lothians and central and south west Scotland.
Fife Police said travellers should expect the Forth and Tay road bridges to be closed to traffic. The force said high winds could further disrupt roads, with fallen trees and other debris.
Forecasters said rain showers in the afternoon will turn into snow by the evening.
Chief Inspector Davie McCulloch, the force’s head of road policing, said: “Travel conditions are forecast to be very difficult on Thursday afternoon and I would urge all drivers to take extra care and only travel if necessary.
“Drivers should prepare to be delayed and are advised to ensure they have sufficient fuel for an extended journey, spare clothing and a fully-charged mobile phone to hand.”
Assistant Chief Constable Allan Moffat, from Central Scotland Police, said: “If the weather is as severe as currently being predicted, then there will be a significant impact on the roads network with a high risk of disruption.
“As with any conditions that can make driving and travel hazardous, I would ask that people drive with caution, plan ahead to ensure routes are open and safe and be prepared for any delays or disruption that could affect their journey.”
A spokeswoman for Aberdeen City Council said road temperatures are predicted to fall below freezing today, which could result in a “flash freeze”.
The Glasgow Loves Christmas campaign said attractions in the city’s George Square will be closed tomorrow because of the weather.
Last night temperatures dipped once rain had cleared, leaving roads icy.
All eight of Scotland’s police forces are warning drivers to be careful.
This morning a lorry and a 4x4 vehicle crashed on the A75 in Barskeoch, near Newton Stewart in Dumfries and Galloway. Police said the icy road was “very dangerous”.
There were also problems on the A939 between Tomintoul and Cock Bridge.
Tay Road Bridge was closed to high-sided vehicles and warnings were put in place for high winds on Skye Bridge, Forth Road Bridge, Clackmannanshire Bridge and Erskine Bridge.
Transport Scotland announced last night that its multi-agency response team (Mart), which involves police, rail operators, road operating companies and the Met Office, will remain operational until at least Friday night.
Transport Minister Keith Brown said tomorrow will be a major challenge for the country’s transport system.
He said: “Potentially many of our main road bridges could be closed at some point tomorrow afternoon.
“According to the Met Office, the worst period will be from 3pm to 6pm and they are confident that wind speeds will exceed 75mph. As well as possible bridge closures, we need to prepare for blown-over vehicles and trees.
“The initial high winds are expected to peak tomorrow afternoon into the evening, so commuters are advised that if they can leave work earlier or work from home, that would be a very sensible step to help avoid possible rush-hour delays.
“We are all working hard to keep Scotland moving and I urge everyone to allow extra time for travel, avoid unnecessary risks and keep checking websites and local radio for real-time information.”