UK weather forecast: Britain set for MONSOON THUNDERSTORM on Friday before 6-week heatwave

Booming thunderstorms will sweep across the Continent and into the UK on a plume of tropical air from Spain on Friday.

Heavy rain falling on parched ground will run off in torrents prompting government warnings to prepare for flooding and travel chaos.

Tens of thousands of lightning strikes threaten power cuts and disruption to transport networks, forecasters warn.

South-east England is in the firing line for the assault according to the Met Office which has issued a thunderstorm alert across the region.

Torrential rain will ease on Saturday when thermometers will rocket plunging Britain into another unrelenting heatwave.

The 38.5C (101.3F) UK highest temperature record could fall by the end of next month with blistering heat expected to hold out for the next six weeks.

Met Office spokeswoman Nicola Maxey said showers will set in on Thursday night before the heavens open on Friday.

She said: “There are some thunderstorms over Spain at the moment and these, with a lot of warm air, are moving up towards us.

“We expect this to reach the UK on Friday hitting southern parts of the country first.

“While there will be thunderstorms brought in with this, there will also be some home grown thunderstorm activity.

“We expect some heavy rainfall in northern Britain on Thursday night with showers further south.

“However we are expecting the main thunderstorm activity on Friday when this warm air arrives from the Continent.”

The weather will turn warmer and more settled on Saturday with the chance the mercury hitting 32C (89.6F) on Sunday, she said.

Temperatures will remain well above average through next week as Britain swelters through what is shaping up to be one of the hottest and sunniest summers on record, she added.

She said: “There will be a bit of a nationwide split next week with the southeast drier and hotter to start with, this then becomes an east-west split later in the week again with the east seeing the highest temperatures.

“However temperatures will remain above average across the country and from Sunday; we are looking at highs of 31C (87.8F) or 32C (89.6F) where there are breaks in the cloud.”

A Met Office warning for thunderstorms is in place from Friday afternoon with the East Midlands; eastern England; London and south-east England and south-west England highlighted most at risk.

Similar heat-driven storms which hit Britain at the end of May saw more than 15,000 lightning strikes light up the skies over a four-hour period.

Met Office chief forecaster Will Lang said more than an inch of rain could fall in one hour leading to floods and travel disruption.

He said: “High temperatures may set off some heavy showers and thunderstorms, which in some places could be slow-moving and persistent, bringing a risk of flooding.

“Should they develop, in the heaviest showers some places could see 30mm of rain [1.18 inches] in an hour, which would likely bring flooding impacts particularly should this fall on an urban area.

“There is a small chance that homes and businesses could be flooded quickly, with damage to some buildings from floodwater.

“Where flooding or lightning strikes occur, there is a chance of delays and some cancellations to train, bus and tube services, particularly during the evening rush hour.”

High pressure will build across Britain at the weekend heralding another lengthy spell of hot, dry weather.

Thermometers will widely rise into the high 20Cs with parts of the country likely to hit 30C (86F) through next week.

Exacta Weather forecaster James Madden said: “Despite some changeable weather this week things will  heat up again this weekend as a substantial area of high pressure builds across the country.

“This will deliver predominantly dry weather and further periods of prolonged sunshine for many into next week although isolated and hard to predict thunderstorms could bubbling up  at times.

“Temperatures could approach the 30C-mark again for several days from Sunday and this will pave the way for a further surge of heat during the final part of July and into August.

“There is still a good chance the all-time temperature record will be breached before the end of summer.”

Met Office figures for summer so far show Britain could be in the middle of one of the sunniest summers for more than four decades.

So far the country has baked under 385 hours of sunshine compared to 669 recorded during the historic 1976 scorcher.

Temperatures have also been consistently above average with a 20.9C (69.62F) average so far compared to 21C (69.8F) in 1976.

A Met Office spokesman said: “If the rest of the summer is average, 2018 will certainly rank in the top 10 warmest summers on record and if we continue to see above average temperatures, it could well be record breaking.”

Thunderstorms will hit as millions of families hit the roads for the great summer holiday getaway, experts warn.

Drivers are expected to make more than nine million leisure journeys between Friday and Sunday, according to the RAC.

Spokesman Rod Dennis said: “This weekend tends to be one of the busiest on the roads for leisure journeys, second only to Easter and Christmas.

“On some popular routes, this may well mean gridlock, especially through the second half of Friday when commuters and holidaymakers will be sharing space on the same stretches of the UK’s roads.”