Londoners have two more days to enjoy the scorching weather until much of the UK is ravaged by thunderstorms.
Monday marked the hottest day of the year so far with temperatures soaring above 28C in the capital, and Met Office meteorologists have said Wednesday could now be even warmer in the south.
Temperatures of at least 29C are being forecasted on a red-hot June 15, but the Met Office has already issued a yellow weather warning for the two days following.
Thunderstorms are predicted to sweep through London and much of the south of England, starting late on Wednesday all the way through to Friday.
The Met Office say there is potential for travel disruption and flooding in "three potential rounds of thunderstorms."
Tuesday is due to be cloudy but still warm with south-east England likely to see the highest temperatures of 24C to 25C, before the mercury soars again the next day.
On Wednesday, temperatures of up to 30C are predicted in London due to a warm front covering the southern half of the nation.
Mr Keates said: "It looks like the full force of the heat is going to come back on Wednesday for southern and central England, Northern Ireland and Wales.
"There's a chance that Wednesday could become the hottest day of the year.
"But there's a big temperature contrast across the North West versus the South East."
Mr Keates added the sweltering start to the week will be followed by "three potential rounds of thunderstorms" moving from Europe on Wednesday night, and again on Friday and Sunday.
The Met Office has issued yellow weather warnings for the storms which could cause flooding and power cuts from 6pm on Wednesday until 6am on Friday.
Warnings cover all areas south of Newcastle with the exception of the western edge of England and Wales, and Northern Ireland.
Monday's record-breaking weather for the year saw crowds flock to beaches and beauty spots.
The UK's previous high of 2021 was 28.3C in Northolt, north-west London, on June 2, but on Monday reached 29.7C in Teddington, Middlesex.
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