Month of rain to fall on Saturday after hot September

A burst of heat at the end of summer will prompt as much as a month’s worth of rainfall and thunder this weekend.

Up to 70mm of rainfall is expected within a few hours on Saturday following unseasonably warm temperatures, reaching 26C in London, on Thursday.

Alex Deakin, a Met Office meteorologist, said that “we will start to see the change” after a grey start on Friday.

“As the cloud breaks in the South, bringing some sunshine for a time, that is then likely to spark some heavy showers come the afternoon,” he said.

“Over East Anglia initially, but then spreading over to parts of the Midlands, Wales and especially south-west England. Some heavy downpours are expected, thunderstorms and hailstones possible as well.”

The Met Office has issued two yellow weather warnings for thunderstorms for Friday and Saturday and warned of damage to buildings as a result of lightning strikes, as well as disruption to public transport and flooding.

Friday’s alert covers most of south-west England, parts of Wales, the Midlands and west London, and is in place from 12pm until 8pm.

The second warning is in place all of Saturday from 1am and covers all of Wales and south-west England, the Midlands and parts of south-east England.

It said up to 70mm of rain could fall in the worst affected areas on Saturday, compared to the average September rainfall across southern England and south Wales of around 60-90mm.

Dan Stroud, a Met Office meteorologist, said: “We are being spoiled by almost summer’s last hurrah, but there’s a bit of a change coming down the line as we move our way through towards Friday, and especially the weekend.”

A “gentle decline” in temperature is expected over the weekend, with highs of 24C forecast for East Anglia on Saturday followed by low 20s in the area on Sunday, he added.

“Successive bands of rain” and “normal conditions for autumn” are expected next week, he added.