Snow is forecast for much of the country, with the travelling public urged to prepare for potentially hazardous conditions in some areas.
The Met Office issued amber "be prepared" alerts and warned of strong winds which could lead to drifting and blizzard-like conditions, particularly over higher areas in the north.
It said four to eight centimetres of snow is likely to fall quite widely in the amber warning areas, with a low risk of more than 10cm (3.94in) locally - even on lower ground. Further north, 10 to 20 cm (7.88in) could accumulate in some upland areas.
The alerts apply to south-west Scotland and Lothian and Borders, Strathclyde, Central, Tayside and Fife as well as southern parts of the Highlands and Grampian for Friday morning into the early hours of Saturday.
Transport minister Keith Brown said the weather could result in a "testing" journey for some people but that the Multi-Agency Response Team (MART) will monitor conditions and provide help across the network. The same warning will also extend into northern England and the Midlands, meaning cross-border road, rail and air links could be affected.
Mr Brown said: "According to the latest Met Office forecast, a combination of freezing temperatures, hard packed ice and fresh snow will mean a testing journey for some people tomorrow.
"I would urge the public to take on board police advice about driving to the conditions, planning ahead and taking notice of travel updates.
"Despite the high level of service and winter treatments provided, sudden weather changes can occur and stopping distances increase tenfold when driving in snow and ice."
Assistant Chief Constable Allan Moffat, from the Association of Chief Police Officers in Scotland, said: "We would urge people to be aware of the threat of disruption and to check with radio and TV bulletins and online before making their journey.
"It is also important that the advice and warnings given to those wishing to travel in the areas affected are heeded as the conditions may be hazardous."