The UK will be lashed by heavy rain and thunderstorms over the next few days as the weather turns tropical and muggy.
Showers coming from the Atlantic will hit southern and eastern parts of the country on Sunday, which will also be hot and humid.
Forecasters say the “tropical” conditions will last until Wednesday, with temperatures reaching up to 29C.
Greg Dewhurst, a Met Office forecaster, said: “A changeable picture will emerge over the coming days with it being on the warm and humid side for many.
“Sunday morning is looking cloudy, with outbreaks of rain in parts of Wales and central England, with heavy showers moving in across southern and eastern England, including London, in the afternoon.
“Most of Scotland and Northern Ireland should remain relatively sunny and dry while temperatures will climb as high as 27C in parts of England.
“It will be warm and muggy and there will be plenty of cloud as high pressure builds on Monday, the day starting sunny and dry before turning wet and windy in north-eastern and western parts of the UK.”
The mercury could rise up to 29C in London and the South East on Tuesday, before conditions turn sunnier and cooler from the middle of the week.
Mr Dewhurst continued: “There’s going to be a very muggy feel, more so at night, so expect an uncomfortable time sleeping, with temperatures in the late teens.”
He said an area of “tropical maritime air” moving in from the south west will hang over the UK over the coming days.
Another Met Office forecaster earlier said that an “odd rumble of thunder may be heard in isolated areas”.
Tom Morgan said: “The main theme over the coming days will be wet weather, in stark contrast to the rest of July.
“Many areas will be very warm and humid with plenty of cloud around, even overnight, with temperatures as high as 20C in the early hours, meaning uncomfortable evenings for sleeping are in store.
“The odd rumble of thunder may be heard in isolated areas, and it’s going to be pretty muggy and humid, typical of conditions seen in tropical countries.
“Temperatures could climb as high as 29C during the day in southern areas, but it’s going to feel uncomfortable and clammy.”
Around 30 to 40mm of rain could fall over Monday and Tuesday in northern, central and western areas, but “nothing too disruptive” and “useful for farmers and gardeners”.
The muggy conditions come after an intense heatwave earlier in the month when temperatures exceeded 40C in some areas of the UK.
