Up to eight inches of snow could fall in parts of the UK this week as cold weather descends across the country.
The Met Office has issued a yellow weather warning that covers much of southern Scotland and north-east England, parts of Yorkshire, and parts of the north-west of England, including Lancashire and Cumbria.
The warning is in force from 10am on Monday until 10am on Tuesday.
Snow and ice could cause disruption across northern parts of the UK, with up to 20cm (around 8in) of snow possible on higher ground.
There is a small chance of up to 10cm (4in) of snow settling at lower levels, which could prove disruptive, forecasters said.
A separate warning for snow and ice is in place in northern Scotland from 4pm on Sunday until 11am on Monday.
Met Office deputy chief meteorologist Rebekah Hicks said: “A notable early winter cold spell will arrive across the north from Sunday and will likely reach all parts of the UK by midweek.
“Temperatures will drop as a northerly airflow develops, bringing in colder Arctic air. This introduces the possibility of snow, initially over high ground in the north from Sunday, with gusty winds also a potential hazard.
“As the cold air spreads south, wintry weather is possible more widely, and a snow and ice warning has already been issued for parts of Scotland and northern England for early next week.”
She added: “Updates to the warnings for wintry hazards are likely, so it’s important to stay up to date with the latest forecast.”
The cold front comes after weeks of mild, above-average temperatures.
Met Office spokesman Grahame Madge said: “It’s going to get colder over the coming days – it’s still pretty mild in the south but there is a cold front that will be sinking south across northern parts of the UK.
“There’s going to be some wintriness in the hills, for example, tonight and into tomorrow. That’s all at quite high levels – Scottish mountains, Lake District maybe. Then we get into our warning period for snow and ice.”
The weather could cause issues on the roads and railways, with longer journey times by road, bus and train services. The Met Office has also warned of the possibility of icy patches on some untreated roads, pavements and cycle paths.
Mr Madge said the cold spell would still be “largely sunny”, with “clear sunny spells”. “Technically and meteorologically, we are not in winter yet,” he added. “It’s still late autumn as for meteorologists winter begins in December – but this is the first really cold spell of the season so far.”
Forecasters say the change in the weather is a result of low pressure moving in.
The AA advised night-time and early-morning drivers to “keep their wits about them as fog becomes likely in some parts of the UK”, and to check their vehicles. RAC Breakdown also warned drivers to look out for the effects of a cold spell on car batteries.
RAC Breakdown spokeswoman Alice Simpson said: “Frost, ice and snow all put more strain on car batteries so if a vehicle struggles to start, it’s either a sign that the battery needs charging or that it’s about to fail altogether and needs replacing.
“We strongly suggest drivers get their battery checked by a mobile mechanic or garage as soon as possible. Taking your car for a 30-minute drive before you need it and switching all electrics off when you finish your journey are effective ways to reduce the chances of an unwanted flat start.
“In freezing conditions, it’s also well worth packing a blanket, warm waterproof coat and gloves, sturdy boots and a mobile power bank for all eventualities.”