Parts of England and Wales will experience a scorching day today before summer heat turns to downpours.
The mercury is predicted to peak at 30C in London as the sunshine sweeps over central, eastern and southern parts of England.
The rest of England and Wales should enjoy temperatures of between 23C and 25C, while Scotland and Northern Ireland will have to settle for a cool but dry day. But from tomorrow the latest mini-heatwave will be replaced with thunderstorms, torrential rain and a risk of flooding.
Forecaster Nick Prebble said: "The nice few days of sunshine will turn to rain tomorrow. There will be showers across the UK and the north will see heavy, persistent downpours with the potential of torrential rain and flooding.
"The unsettled weather and risk of showers will linger across the weekend."