There could be a danger to life in parts of eastern Scotland, where an amber alert has been issued for Friday.
Image source, Eddie MitchellMotorists are being warned to stay off roads as the UK prepares for “atrocious” conditions caused by heavy rain.
Some rail lines have been impacted, with disruption between Tonbridge and Hasting caused by flooding in a tunnel.
West Sussex Fire and Rescue Service urged people to “only travel if necessary” after 20 cars became stuck on the A27.
The Environment Agency has issued 27 flood warnings and 104 flood alerts.
A band of rain – which arrived on Wednesday in Cornwall – will travel across England before passing over Scotland’s east coast on Friday.
The Met Office has issued weather alerts, including a yellow warning for rain on Thursday.
Craig Snell from the Met Office said many places in the South East had already seen “more than their month’s share of rain”.
“The warning areas are where we are most concerned about the risk of flooding but it doesn’t mean that the areas outside them are not going to see some pretty atrocious conditions.”
He said Scotland could see “two days of persistent rain” and this may result in snow falling in the Scottish Highlands – although this is not unusual for November.
The M23 motorway in Sussex was closed after heavy rain caused disruption. The road between Junction 10 for Crawley and Junction 11 for Pease Pottage was reopened after several hours, but some lanes remain shut.
Parts of Wales are also set to experience heavy rain, with the Met Office predicting 30-40mm (1.1-1.5in) of rain could fall over a 24-hour period.