After basking in the year's hottest temperatures at the end of the week, Britain is now braced for torrential downpours and storms that could cause flash flooding across large parts of the country.
The Environment Agency has warned almost every county in England and Wales is at "medium" risk of flooding, and has issued dozens of flood alerts, the majority of which are in the Midlands, South West and South East.
Despite expected storms, forecasters are also warning that Britain's heatwave could continue in parts of the country until tomorrow morning.
A "yellow" warning of a heatwave has been issued for the UK today, advising people to be "alert and ready".
The Met Office said there was a 60% chance of a heatwave continuing until early Sunday, with high levels of humidity.
But in an "amber" warning of rain for England, eastern and central Wales, the organisation also warns that heavy, thundery showers that developed overnight will move northwards during the day.
The Met Office said: "Not everywhere within the warning area will see thunderstorms, and indeed some spells of warm sunshine are expected at times, but where thunderstorms do form, some torrential downpours are likely with frequent lightning, large hail and locally strong gusts."
Viewers have posted dramatic pictures of the storms which ravaged the UK last night. The photos were posted on the ITV News Facebook page.
It seems thousands of people were woken up by loud claps of thunder, seemingly constant flashes of lightning and torrential rain.
Britain is set to bask in the sunshine in the next few days with health officials issuing guidance on how to stay safe in the sunshine.