The Met Office has issued a thunderstorm warning running throughout Thursday that is set to affect millions - and could see some hit with a week's rainfall in an hour.
It warns that there is a yellow warning for storms and heavy showers covering almost all of the south of England.
Forecasters say there are risks of sudden flooding, 'difficult driving conditions' and a risk of delays to public transport services.
They have also warned of a 'slight chance' of power cuts in the affected areas, and a chance of flash floods.
The storm warning covers dozens of areas across three regions of England:
