A powerful American jet stream paired with a snaking cold front will plunge half of Britain back into a heatwave and elsewhere into chilly winds.

A surge of desert heat from the Continent will push temperatures back to near-record highs this weekend, experts warn.

But as thermometers rocket across southern regions, Scotland and the north will shiver behind a trailing cold front.

Met Office meteorologist Alex Deakin said: “A weather front is going to be a really important player into the weekend because it marks a boundary between the warm and humid air across England and Wales and the cooler and fresher conditions across northern Scotland.

“There is quite a strong contrast in temperatures with East Anglia and the southeast getting close to 30C, whereas the far northwest will be getting to 14C or 15C with a fairly brisk wind.

“So, how Saturday pans out will depend on the position of this weather front, and if you have plans for the weekend, then the position of this weather front will be crucial.”

Temperatures are expected to peak on Sunday as high pressure builds across southern Britain.

This will be boosted by the jet stream as it fires out of the United States, fuelled by powerful upper-air winds, Deakin explained.

Temperatures rocket into next week

He said: “Across North America, the jet stream is getting a bit of a push from some stronger winds high in the sky, pushing the jet stream south and buckling it.

“This causes a dip in the jet stream, and this translates across the UK as the jet is more north-to-south rather than east to west.

“That means that as high pressure builds to the east under a ridge, we will tap into some heat, building up from the south, and the hot air pushes northwards from Sunday to Monday.”

Thousands of revellers gathered in the West Country for Glastonbury face a stifling festival.

Met Office Alex Deakin describes the jet stream charging out of America

As the mercury rockets at Worthy Farm, bookies have slashed the odds on temperature records toppling.

Coral spokesman John Hill said: “With temperatures remaining hot, festival goers are set for a sweltering Glastonbury this year, and it looks set to be one of the hottest on record at the music event.”

As Britain sizzles to the end of a flaming June, forecasters predict July could be fierier.

Temperatures going into next month are expected to head into the mid- or possibly high-30Cs.

Temperatures will rocket

Jim Dale, meteorologist for British Weather Services and social commentator, said: “There is a chance we will go back into the 30Cs through the start of July, and later in the summer, we could even see higher temperatures.

“With the weather so far during spring and summer, it would not be impossible to beat the all-time record, and this is something we are at greater risk of as the climate changes.

“This weekend, southeastern regions will see the highest temperatures.”