Forecasters are warning of the communities could be cut off, travellers could be stranded and homes left without power as the cold snap tightens its grip on the North East.

The Met Office has upgraded weather alerts issued earlier this week from yellow to amber warnings, predicting heavy snow between 3pm on Wednesday and 6pm on Thursday in north-west Scotland and the Northern Isles.

The fresh warning comes after temperatures dropped to the coldest of the winter so far, with the mercury dropping to minus 14C in Dalwhinnie during Tuesday night, the lowest January temperature in Britain since 2019.

The Scottish Farmer: There are warnings trains could be disrupted There are warnings trains could be disrupted (Image: PA)

The Met Office says that some areas could see an extra 15 to 20cm of snow, with their upgraded warning stressing that "frequent" heavy snow showers will affect the Northern Isles and northwest Scotland, "disrupting travel across the region".

The alert states: "Travel delays on roads are likely, stranding some vehicles and passengers. Power cuts are likely and other services, such as mobile phone coverage, may be affected.

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"There is a good chance that some rural communities could become cut off. Some delays and cancellations to rail and air travel are likely."

The Scottish Farmer: There is a warning motorists could be stranded There is a warning motorists could be stranded (Image: PA)

Forecasters had predicted some snow-covered parts of Scotland could reach minus 15C overnight, which would have been the coldest January night for 14 years, when minus 22.3C was recorded in 2010.

Met Office said more than 40cm of snow may fall on high ground in north-west Scotland by the end of Friday.

Tuesday night did mark the coldest night this winter so far, beating the minus 12.5C daily minimum temperature recorded at Altnaharra in the Scottish Highlands on December 3.

Freezing temperatures and snow will continue for much of Britain this week because of cold Arctic air before “potentially disruptive” stormy weather lands over the weekend.

A “cold plunge of Arctic air” has moved south across the whole country over the past few days, making it 5C to 6C lower than usual for this time of year, the Met Office said.

A Met Office spokeswoman said the low temperatures are also due to how long the cold snap has lasted.

She said: “It’s due to the prolonged nature of this cold spell, it will have been lasting for quite a few days.

“A build up of snow, as well, just allows for the temperatures to get colder and colder and we don’t often see a cold spell last three to five days.

“The air is coming directly from the Arctic, so it is exceptionally cold air.

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“It’s staying cold until Friday, and then looking further ahead into the weekend we’ve got some deep areas of low pressure pushing in, so a big change in weather type, and we could see some stormy conditions by the end of the week.

“The cold isn’t lasting right to the end of the week, but we have a very different type of potentially disruptive weather arriving.”

The weather is forecast to turn stormy on Sunday, she added.