A fresh amber "be prepared" warning for snow and ice has been issued for mostly western parts of the country.

Motorists have been advised of a "tricky commute for the morning rush hour" amid treacherous road conditions.

Snow showers combined with high winds could create temporary blizzard conditions, particularly over hills, while "thundersnow" caused by hail and lightning may cause disruption to power supplies.

Police Scotland said there was a high risk of disruption on roads and urged drivers to consider whether their journey was necessary.

A yellow weather warning has been in place for much of the country since Thursday, but the new amber warning affects Glasgow, Lanarkshire, Ayrshire, Renfrewshire, East Renfrewshire, East Dunbartonshire, Inverclyde, Dumfries and Galloway, West Lothian, the Scottish Borders and Falkirk.

Superintendent Louise Blakelock, of Police Scotland's road policing division, said: "Due to the upgraded warning from the Met Office it has been necessary to update our travel advice.

"We've been working closely with our colleagues at Transport Scotland, the Met Office and local councils to assess the conditions.

"Therefore, for the duration of this updated warning, there is a high risk of disruption for road journeys and there is a high likelihood of the conditions for travel being very poor.

"Those heading out on the roads should be aware of these risks - ensure you have a fully charged phone, warm clothing, and leave extra time for your journey."

The Met Office said: "A further 10 to 15 cm is likely to build up above 150m with 20 to 30 cm possible over the highest routes - although (as is the nature with showers) some areas will see less.

"At low levels, 2 to 6 cm, perhaps locally 10cm, would be more likely."

The forecaster's guidance is that an amber weather warning means you should be prepared to change your travel plans for your own safety.

Friday marks the end of a week of wintry conditions for Scotland, with regular snow showers causing disruption to transport and schools.

Heavy snowfall on Tuesday night left hundreds of drivers stranded on the M74, with mountain rescue teams drafted in to help overnight.