Storm Bert is expected to bring high winds and potential flooding as it hits the UK on Saturday.
Disruption is expected over the weekend, with gusts of 40-60mph (65-96km/h) forecast in Scotland, Northern Ireland, north Wales and northern England.
An amber warning for snow and ice has been issued for central Scotland, while numerous yellow warnings for rain and wind are in place for Saturday and Sunday.
The Environment Agency says heavy rain could lead to areas of localised flooding in northern England.
The turbulent forecast comes after an early cold snap brought snow and ice to many parts of the UK - with temperatures expected to remain low on Friday.
The Met Office has issued a number of weather warnings for northern and south-west England and Scotland for Saturday and Sunday, as Storm Bert is set to cause multiple weather hazards.
A yellow warning for wind has also been issued for Scotland and parts of Northern England from 05:00 to 19:00 GMT on Saturday.
Strengthening winds will be felt by all - but some of the strongest gusts, of up to 70mph (113km/h), will be around the Irish Sea and southern England coasts.
High winds will continue at times well into Sunday and Monday as Bert makes slow progress eastward across the UK.
Strong winds have the potential to cause damage and disruption to the transport network and buildings, with power cuts also possible.
Network Rail is already advising passengers to check journeys before they travel this weekend.
Across south-west England and Wales, a Met Office yellow warning for rain says that, throughout Saturday, 50-75mm (2-3in) of rain could fall widely.
The heaviest and most persistent rain will fall in south Wales and south-west England, where there could be as much as 150mm (6in) - which would be the whole of November's average rainfall in just a day.
As rain spreads across the country, there will temporarily be a bit of snow on the hills of Northern Ireland and Wales.
Bert is also expected to bring heavy snow and blizzards to higher ground in northern England and Scotland, making any travel very difficult.
The Met Office is forecasting as much as 20-40cm off snow on higher ground in an area north of Scotland's central belt, where an amber alert for heavy snow and ice will be in force between 07:00 and 17:00 on Saturday.
Police are urging people not to travel on Scotland's roads on Saturday as the country braces itself for more heavy snowfall.
Met Office spokesman Oli Claydon said Storm Bert was a "multi-hazard event" for the UK.
He added: "Because of the different nature of the weather across the UK, people really need to have an idea of what the forecast is for them specifically.
"Further south it's wind and rain, further north it's snow then rain and wind. So it really depends on where you are in the UK."
An amber cold health alert is in place for much of England until 18:00 on Saturday.
It means there is an increased health risk to vulnerable people, and the UK Health Security Agency (UKHSA) has urged people to check on those who may be at risk.
Some people may be eligible for cold weather payments - a government benefit top-up to help with fuel bills during times of exceptionally cold weather.
Meanwhile, the freezing cold is expected to remain across the UK on Friday - though temperatures are set to rise as Storm Bert approaches from the Atlantic.
In Scotland, temperatures dropped to -6C (21.2F) on Friday morning. Across the UK, they are not expected to reach any higher than 6C throughout the day.
Friday night is expected to be the coldest of the autumn so far, with temperatures across north-east Scotland plummeting to around -12C.
But by Saturday, Wales, as well as central and southern England, could see temperatures of up to 12-15C.
It will remain cooler in the north, at 2-7C, before the milder weather spreads to all parts by Sunday.
A risk of ice remains on Friday, with parts of England and Wales set to see rain, sleet and a little snow. Northern and western Scotland will see more significant snow ahead of Bert's arrival.
The cold weather has already caused disruption.
More than 100 schools across the Scottish Highlands and 30 in north Wales were closed on Thursday, while almost 200 schools in Devon and Cornwall shut or were partially closed due to the snow.
