Forecaster Alex Burkill said: 'The storms have kicked off and we're seeing some pretty hefty showers, particularly in London, with thunder, lightning strikes and heavy rain. There are some pretty intense showers that have turned thundery.'
The storms have now moved into the west Midlands, one of the areas under a yellow weather warning, and Wolverhampton Station is now under a few inches of water.
But the UK can look forward to a dryer day tomorrow, with temperatures up to 24C, and Mr Burkill said showers should clear by around 9pm - earlier than they did yesterday, when the torrential downpours caused surface flooding which endangered lives.
It comes as forecasters warned similar storms would continue today after more than a month's worth of rain fell yesterday, which flooded parts of London and nearly drowned another man who was forced to make a dramatic escape as his car filled with water.
Fourteen flood warnings were in place across the midlands, south east and south west this morning as the country braced itself for more heavy downpours amid unusually warm weather for June.
And more thunderstorms are expected like those yesterday which left a father and his two children in hospital after being struck by lightning after a school sports day in Northern Ireland yesterday.
George Allen was on the phone while holding his two children's hands when they were struck. He and his son, five, are in a critical condition and his daughter, 7, is now said to be stable.