A "significant" barrage of snow is set to fall across the UK from today alongside bitter winds and thundery rain, as winter moves in early.
Temperatures struggled to remain much above zero overnight into Thursday across the whole country with Met Officeweather warnings for snow and ice in place until midday tomorrow.
Some areas were expected to plummet as low as -10C.
Scotland could see 2cm of snow in low levels, with 2-5cm above 200m and up to 10cm over the highest routes, leading to travel delays, said chief meteorologist Dan Suri.
And despite some sunshine at times in the coming days, it's going to remain very chilly right into the weekend with freezing winds exceeding 40mph in parts.
BBC forecaster Helen Willetts said the much colder weather on its way will prove "a real shock to the system" with snow showers "coming down really thick and fast" - initially in the North.
And while cloud and rain are the worst of it further south to begin the day, temperatures will drop low enough for a "smattering of snow" over the Welsh mountains and tops of the Midlands.
"The significant snow will fall further north, and in Scotland at low levels as well and with widespread frost here. For northern England and Northern Ireland ice will make things pretty treacherous," said Ms Willetts.
The afternoon is expected to see a return to heavy and thundery showers in the west of England and Wales, while sunshine pushes through in Scotland and Northern Ireland.
"But wherever you are, sun or rain, it will be a cold day," continued the meteorologist.
Strengthening overnight winds from tonight will see the renewed risk of frost and a "more significant snow as these weather fronts migrate westwards".
"Devil's in the detail, really, as we go through Thursday night into Friday, but it does look like we'll see some significant snow in places, and even further south we could see a smattering of snow, primarily on the hills," said Ms Willetts.
Tomorrow will be the windier of the two days, with gales around the Irish Sea coast making the temperature feel much lower than it is.
The Met Office is forecasting a gradual easing of showers over the weekend and "increasing amounts of sunshine" by Sunday.
"Overnight frost and fog developing as skies clear, whilst remaining rather cold by day," it adds.
However, long range forecasts suggest a return to snow next week.
Temperatures going into next week are also predicted to be lower than the average annual temperature, which is usually around 7-9C.
UK 5 day weather forecast
Wintry showers over Scotland and Northern Ireland increasingly confined to west and north coasts. Rain for much of England and Wales with some hill snow for northern England and Wales. Cold. Windy in the far south.
Rain over England and Wales, pushing into east Scotland and northern England later with some snow here, mainly for hills. Very cold in the northwest with severe frost in places.
Cloudy with bands of rain across much of the UK. Come snow, mainly over Scottish hills. Mostly dry in NW. Cold for most, particularly in parts of the south.
Outlook for Saturday to Monday:
Showers will gradually ease over the weekend with increasing amounts of sunshine by Sunday. Overnight frost and fog developing as skies clear, whilst remaining rather cold by day.