Motorists making essential journeys during expected thunderstorms are being advised to modify their driving style to stay safe.
The AA warned that roads could become “hazardous” after the Met Office issued severe weather warnings for Saturday.
It urged drivers caught in sudden downpours to slow down and leave more space behind the vehicle in front.
This is a legal requirement in some countries during thunderstorms, but in the UK it is only advised in the Highway Code.
AA patrol of the year Nick Powell said: “If you must travel, reduce your speed to account for the conditions and leave plenty of space behind other vehicles.
“Allow extra time, as it’s likely your journey will take longer than usual, and ensure you have plenty of fuel or electrical charge if driving an electric vehicle.
“In a thunderstorm, water can quickly run off the road, causing flash flooding.
“It only takes one incident to cause long tailbacks, so keep tuned to local traffic reports and reduce your speed as appropriate for the conditions.
“Never risk driving through floodwater.”
Mr Powell said drivers who experience aquaplaning – when control of a vehicle is lost due to a layer of water between the tyres and the road surface – should “ease off the accelerator to slow down gently”.
He added that all motorists should keep a fully charged mobile phone with them.