Thunderstorms are set to batter parts of the UK just four days after the country saw the hottest day ever recorded.
Several flood warnings are in place as thunder, hail and strong winds are set to hit.
The Met Office has issued a Yellow weather warning for thunderstorms across much of the South West and Wales for Tuesday.
Just before 1am on Monday, the Environment Agency advised the Greater Manchester region had 17 flood warnings in place, meaning immediate action was required.
Forecasters said while the heavy rain will clear on Monday, a second band of low pressure will hit the country on Tuesday.
The warnings come less than a week after the highest temperature for Britain was ever recorded in Cambridge, at a huge 38.7C.
Met Office meteorologist Mark Wilson said parts of the South West and Wales will see heavy downpours and could get between 30mm and 40mm of rain.
The average rainfall for the region in July is 81mm, he added.
Mr Wilson said: "An area of low pressure will bring the risk of quite heavy thundery showers into Tuesday.
"There's definitely a risk of flooding.
"Thunderstorms are a concern - there could be as much as 30mm to 40mm of rain. That's quite a lot of rain flowing in quite a short period of time."
The Met Office also warned there could be delays and cancellations to trains and buses as well as difficult driving conditions and road closures due to the storms.
The new warning follows a weekend of heavy downpours with half a month's worth of rain falling across parts of the UK leading to travel disruption and floods.
A Yellow weather warning for rain was in place across parts of the Midlands, the North West of England, Northern Ireland and south-west Scotland on Sunday.
Forecasters said that parts of the North West had seen 40mm to 50mm of rain in about 24 hours, with 52.2mm recorded between 11am on Saturday and 11am on Sunday at Greenfield near Oldham.
The Met office said that the monthly average rainfall for the North West in July was 89.5mm.
The Environment Agency had issued 30 flood warnings on Sunday evening, the majority in the North West region, and urged people to avoid swollen rivers and not to drive through flood water.
Parts of the North West were hit with floods with cars left almost fully submerged.
Additional reporting by Press Association
