London and the South East will be hit by extremely heavy showers on Wednesday, the Met Office has warned.
The UK's weather service has issued a yellow weather warning for the area, which means people should plan ahead due to possible travel delays. It said the warning will be updated “as confidence in developments increases”.
Bad weather is expected to spread north and leave much of England and Wales affected throughout the day. Thunder and lightning are also possible across parts of East Anglia and the South East during the afternoon.
Most areas in the warning zone should experience between 15 and 30 mm of rain, but in the worst affected places this will reach between 40 and 70 mm, the forecaster said.
The Met said the bad weather was the result of a deepening area of low pressure over the Bay of Biscay, just off the west coast of France, which is set to push north towards the UK.
On Thursday, the heavy rain is expected to subside in most of the South East, but might continue in Oxfordshire and Buckinghamshire.