A severe weather warning has been issued as storms are expected to hit Britain on Saturday.
Forecasters predict heavy, thundery rain will batter parts of England, Wales and southern Scotland.
The Met Office has urged the public to be aware of the potential for localised flooding due to the intensity of the storms.
A yellow severe weather warning has been issued, meaning there is a m oderate risk of some damage to infrastructure and local disruption.
Eddy Carroll, Met Office chief forecaster, said: " Warm, humid air is likely to be pulled northwards from France late on Friday and during Saturday.
"Within this air mass, there is an increasing likelihood that heavy, thundery showers will break out. It is likely that many places within the current broad warning area will miss the worst of the storms; over the next few days it may be possible to focus on the areas most at risk."
The rainfall is not expected to last for a long period of time, but short, sharp downfalls could cause flooding. There is also a chance of hail.
Temperatures will be highest in the South East, where the mercury could hit the mid to high 20s.
The Met Office stressed that warm, humid conditions and thunder storms are often experienced in the UK.
Last month the Shard in south London - western Europe's tallest building - was struck by lightning during a thunderstorm.
A landmark study by the Met Office and Newcastle University published earlier this week warned that climate change could result in heavier summer rainfall in Britain, which in turn could increase the risk of flash flooding.