Giant elements of Scotland and areas of northern England, together with the Pennines and the Yorkshire Moors, might see snow and icy situations and journey disruptions.
The mercury is anticipated to drop to as little as -7C (19F) in a single day on Wednesday in Aberdeenshire, jap Scotland.
Elements of the south will even start to really feel the winter chill, with temperatures dipping right down to -1C (30F) in south-west London.
However the coldest climate is anticipated in western Scotland in a single day on Thursday, the place temperatures might drop to an icy -10C (14F).
The Met Workplace mentioned the chilly spell is anticipated to final till Friday, however that the weekend would see brighter climate and even some sunshine.
It added that temperatures going into subsequent week could be decrease than the typical annual temperature, which is often round 7-9C (45-48F).
Chief meteorologist Dan Suri mentioned: “It will actually really feel extra wintry this week, with colder climate bringing a danger of frost, ice and wintry showers.
“The danger of snow accumulating is essentially confined to the northern half of the UK – primarily over larger floor in Scotland, Wales and northern England.
“By Thursday morning elements of northwest Scotland might see 2cm of snow accumulations to low ranges, with 2-5cm above 200m and as much as 10cm gathering over the very best routes, resulting in some journey disruption.”
Snow and ice warnings are in place for elements of Scotland till 12pm on Thursday, together with an ice warning for Northern Eire on Wednesday night time.
Visitors Scotland operator supervisor Douglas Cairns mentioned a document variety of gritters had been made accessible to maintain site visitors shifting this winter.
“The primary extreme climate warning of the winter for snow and ice is at all times a well timed reminder for folks to verify they’re winter prepared and have made applicable preparations,” he mentioned.
However deputy chief meteorologist, Dan Harris, mentioned that regardless of the chilly and unsettled climate – together with freezing fog – all was not “doom and gloom”.
“We’re keeping track of different areas the place there may be potential for disruptive snow – specifically central and south-east England and the hills of northern England,” he mentioned.
“It will keep chilly into the weekend with rain, showers and hill snow persevering with throughout many areas, together with in a single day frosts.
“We might additionally see some cussed areas of freezing fog develop extra broadly, which presently of 12 months can persist all day.
“Nevertheless, it is not all doom and gloom, as there’s prone to be an elevated likelihood of dry, vibrant, and maybe even sunny climate on supply because the weekend progresses.”