Following the balmy weather experienced by southern England recently, the weekend is set to be much cooler, with peak temperatures expected in the mid-twenties on Saturday and Sunday.
The south of England and Wales is expected to get the worst of the rain on Saturday, while the west of Scotland and Northern Ireland are likely to be sunniest and mostly dry after a week of heavy rain.
The storms may begin to head north as we move into Saturday evening, though most of Scotland should remain dry.
The weekend's storms are expected to cause flooding, leading to possible travel disruption, including road closures and delays and cancellations to train and bus services. There may even be power outages and damage to some buildings from floodwater, lightning, hail or strong winds.
Despite the cooler temperatures, the week's humidity is set to continue, with nights continuing to be close and muggy.
It's been another warm or mild night for many of us.
Here's a look at the latest temperatures across the UK 👇 pic.twitter.com/YZOQ5OnxN9
— Met Office (@metoffice)
Matthew Box, a Met Office forecaster, told PA: "Saturday will begin mostly cloudy for most areas across the UK but as the day goes on showers will start to break out in the south and south east of England.
"As the day progresses further there's a chance of some rumbles of thunder and potentially some hail and lightning.
"The risk of thunder will start to push further north on Sunday, with central parts of England and Wales facing heavy rain and the chance of flooding."
However, areas in Scotland and north western England and Northern Ireland are expected to stay dry with occasional sunshine.
Mr Box said this is due to winds, creating an "east-west" split in northern areas.