Forecasters have warned so-called “thundersnow” – a thunderstorm that produces snow instead of rain – could hit large swathes of Scotland and northern England, knocking homes off the power grid.
The Met Office has warned of dangerous weather conditions on Thursday and Friday, and the forecaster said there could be as much as 10cm of snow falling on the highest ground, as well as the risk of dangerous icy patches and of lightning strikes from isolated thunderstorms.
Thundersnow is not meteorologically different to thunder in the summer, but rather than hail or rain there is snow which can affect the acoustics of the thunder.
The Met Office added that the prospect of thundersnow was driven by the same conditions which cause thunder in the summer, the difference in temperature between the ground and the air surrounding it.
Grahame Madge, spokesman at the Met Office, said: “Because you have got that differential it’s possible, quite easily, for warm air at ground level when it heats up to start to rise very quickly up through the cold air and that’s what creates the potential for thunderstorms, so we are likely to see along with the other wintery showers, likely to see hail and snow.”
The yellow weather warning is set to be in place at 8pm on Thursday until 11am on Friday, and the alert, which includes Glasgow, stretches along the east of Scotland and into the north of England beyond Manchester. It also includes part of Northern Ireland, the Met Office said.
The alert also includes the Highlands and Islands, Central, Tayside and Fife, the south-west, Strathclyde, Lothian and Borders, the Met Office said, which warned of the potential of power supplies being knocked out by lightning strikes.
On Thursday, the Met Office issued a separate warning of snow, which stretches from the Highlands, through Glasgow and Edinburgh, and into the north of England, and warned of disruption to roads.
It said many areas would see one to two hours of snow, with a risk of temporary slushy accumulations above 100-150m, with snow leading to difficult travel conditions.
On higher routes, forecasters have predicted strong winds could lead to drifting and temporary blizzard conditions, and the alert is in place from 10am to 4pm.
Madge said: “We have got an area of high pressure across the UK, that will remain in situ until the early hours of tomorrow morning. Then we will start to see the weather front coming in.
“As conditions get cold tonight, we’re seeing temperatures drop down to freezing quite widely. As we get the cold air, that will bring the temperatures right down, we’ve got the weather front coming in from the west and that moisture is going to bump into the cold air and where you get that you will get snow.”
As winter begins to bite after a record-breaking mild new year, in the early hours of Thursday temperatures could feel as cold as -4C in Glasgow while in Edinburgh the Met Office has said commuters would face temperatures as low as -3C.
In Braemar, Aberdeenshire, the mercury could plunge to -8C in the early hours, and when the wind is taken into account it could feel as cold as -11C.
In Inverness, the northernmost city in the country, temperatures will feel as low as -4C and it will remain bitterly cold throughout Thursday.
In advance of the freezing temperatures, Traffic Scotland has urged people to drive with care because of the risk of ice.