Major flooding has caused chaos on roads in Surrey and West Sussex, with reports of many vehicles being stuck in floodwater after heavy rainfall.
The Met Office said 3in (7cm) of rain fell in three hours in the worst-affected area, Duncton in West Sussex. High winds also hit south-east England.
The A285 Dunction High street was flooded, along with the A29 between Slindon and Pulborough.
Floods closed the A27 near Chichester and the A272 at Haywards Heath.
West Sussex Fire and Rescue Service said crews were called to dozens of incidents where houses and flats had been flooded to a depth of about 2in (5cm). The Storrington and Petworth areas were worst affected.
It said it was receiving a high number of flood-related calls and, with more rain forecast, urged the public to call 999 only if there was a risk to life or risk of serious property or environmental damage.
Motorists were warned not to attempt to drive through flooded roads as vehicles may become stranded or swept away.
Sussex Police said that since 0600 GMT they had dealt with more than 40 weather-related incidents on the roads including those in Pagham, Middleton, Selsey, Bury, Fishbourne and Chichester.
The Met Office said there was also flooding in the Farnham area of Surrey.
Also in Surrey, the A287 was blocked at Haslemere.
The storms in the early hours of Tuesday followed a weather warning issued by the Met Office for parts of south-east England.