Storms that brought flash flooding to parts of Wales and Shropshire are expected to extend into south-east England on Saturday.
The Environment Agency has 14 flood warnings and 58 flood alerts in place in England and Wales.
Part of the A49 in Shropshire is shut, and three people were rescued from their homes in the county overnight.
The Met Office has issued an amber weather warning – meaning the public should be prepared for heavy rain and localised flooding – for parts of south-east England, the Midlands and East Anglia.
Up to 10mm (0.4in) of rain an hour fell in parts of Wales, the Midlands and East Anglia on Friday.
Eight flood warnings are in force for the Midlands. Warnings are also in place in the South West and Anglian regions.
There are currently no flood alerts or warnings for Scotland.
An Environment Agency spokesman said: “We are urging people across central and eastern England to remain vigilant as heavy thunderstorms are forecast to affect large swathes of the country.
“Locally intense showers falling on already saturated ground could lead to surface water flooding and possible river flooding from fast responding rivers, particularly across parts of the Midlands and East Anglia.
“The Met Office warns that many areas are expected to see between 20mm and 30mm of rain, but some parts could see up to 60mm – almost a month’s worth of rain – in just a few hours.”
John Curtin, the Environment Agency’s head of incident management, said there was a combination of saturated ground, high river levels and further forecasts of torrential rain.