Parts of Britain could see two inches of rain on Saturday, less than a fortnight after parts of the Midlands and north of England were soaked by floods.
Yellow weather warnings are in force across the country throughout the day after the rain started to fall in the South West overnight and will move north towards Scotland throughout the day.
In the East Midlands and North East the Met Office is warning that flooding is likely until midnight, as people continue the clean-up from the deluge earlier this month.
Wales, central and south-eastern England will escape the worst of the showers.
Met Office forecaster Greg Dewhurst said: “It’s a pretty unsettled start to the weekend, and a very cloudy day today, with heavy rain pushing its way north throughout the day.”
Nine flood warnings are in place throughout England on Saturday, mainly in the South West and North East, alongside 85 less severe flood alerts.
Firefighters in Devon and Cornwall warned drivers to stay away from flooded roads after a number of calls overnight to stranded cars.
Mr Dewhurst said other rainy areas could also see problems.
He added: “Some places could see 40mm to 50 mm of rain. There’s quite a bit of rainfall to come in the next 24 hours.”
The wet weather will subside on Sunday.
Two yellow weather warnings are in place for the east and north of Scotland until 9am on Sunday, but for most, the rain will have cleared.
Mr Dewhurst said: “On Sunday the rain will ease away. It’s looking like a much brighter day for many.”
Earlier this month, the Army was called in to assist stricken communities after towns and villages around Doncaster and Sheffield and parts of the Midlands were drenched by heavy downpours.
Doncaster Council said 970 homes and businesses in the town were affected by the rain between November 7 and 15.