New weather warnings for rain have been issued around the UK, ahead of what is expected to be the hottest day of the year so far.
Temperatures could reach as high as 27C on Sunday, but the recent warm and sunny spell could disappear by the end of the day.
Three yellow warnings for thunderstorms remain in place for Sunday, but the Met Office has also issued new warnings for rain in south-west England.
Spells of heavy rain area also expected to hit eastern areas of Northern Ireland on Monday, with a warning in place from 12pm until 6am Tuesday.
In areas of south-west England, including Cornwall and Exeter, heavy rain is likely to bring some transport disruption and possible flooding in a few places between 8am and midnight on Monday.
The same warning is in place for southern Wales on Monday, where heavy rain is forecast for areas including Swansea and Cardiff between 8am and midnight.
The Met Office advised those living in areas affected by rain warnings to prepare for disruption to public transport and the possibility of some interruption to power supplies.
Thunderstorms could strike the west of the UK on Sunday, including the majority of Wales, with a warning in place between 1pm and 11pm.
Another storm warning has been issued for the western half of Northern Ireland between 12pm and 7pm, while a third is in place for western parts of Scotland between 2pm on Sunday to 3am on Monday.
Honor Criswick, a meteorologist at the Met Office, said the storms might “band together” in areas across the UK, resulting in intense bursts of lightning and heavy rainfall.
She said: “In the areas with heavy showers, it’s expected to get a bit gustier as well, and surface water flooding is also a possibility.”
It comes as Sunday is expected to be the warmest day of the year so far before the rain and thunder rolls in.
Ms Criswick said temperatures are expected to peak on Sunday before it starts to become cooler again next week.
She said: “We might seen highs of 27C in London today, and it might just reach 28C in areas of central England and the South East as well, which is where we’re likely to see the best of the weather throughout the day. It’s likely to be a bit muggy in places too.
“But today is likely to be the peak. From tomorrow onwards, things will start to get a bit cooler.
“It will still be fairly warm, with temperatures in the high teens and early twenties, but cooler than it has been over the past few days.”
On Saturday all four home nations recorded their hottest days of the year so far. Herstmonceux, East Sussex, had the highest at 25.9C, slightly ahead of Cassley in northern Scotland where a temperature of 25.7C was recorded.
Gogerddan in Wales reached 25.1C on Sunday, while temperatures in Northern Ireland peaked at 23.8C in Magilligan.
A warm dry day for most of the UK 🌞
Check out Saturday's weather extremes below ⤵️ pic.twitter.com/xgR4rQA2SL
— Met Office (@metoffice) May 11, 2024
However, Simon Partridge, a meteorologist at the Met Office, said the year-so-far records were “not likely to last long” because forecasters expect it to be even warmer on Sunday.
He added: “The difference (on Sunday) is that it is not likely to be as warm for Northern Ireland, Wales or Scotland.
“The really warm air will probably be confined to southern and eastern parts of England, with temperatures expected to peak in central parts of the country at around 27C.”