A yellow weather warning has been issued for London and the south east of England.
The Met Office has warned heavy rain may cause travel disruption and flooding this week from today, July 12.
Slow-moving, heavy showers, with some thunderstorms, are likely to continue to break out during today.
This may lead to torrential downpours in some places with 20 to 30mm of rain in an hour and perhaps in excess of 60mm in some spots in two or three hours.
There is also a chance of more persistent heavy rain developing over parts of south east England for a time during the afternoon or evening.
The weather forecast predicts homes and businesses could be flooded, causing damage to some buildings.
Fast flowing or deep floodwater is possible, as are delays or cancellations to train and bus services.
Spray and flooding could lead to difficult driving conditions and some road closures, with some communities becoming cut off by flooded roads.
The Met also warned of possible power cuts and loss of other services to some homes and businesses.
This comes following flash floods in Havering at the end of last month.
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