UK to sizzle in 'unusual weather phenomenon' with six parts of England hottest

The UK faces an unusual weather phenomenon which will send temperatures surging again in days. The Foehn effect, where air warms and dries as it passes across mountains, could see temperatures soar once more after the hottest days of the year.

After 25C highs on Friday and Saturday, marking the hottest weekend of the year so far, mercury will spike into the twenties once again. The best of the weather - which will be "hot" - is forecast to sweep Kent, Cambridgeshire, and the North West, including Merseyside, Greater Manchester, Yorkshire and Lancashire.

The Foehn effect is where air on the downwind (or lee) side of a mountain is warmer and drier than air on the other side. When the air is forced up over a mountain, it cools and condenses to form clouds, bringing rain to the upwind side of a mountain.

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When the air then descends down the other side, it's much drier and that means it ends up warmer. In its outlook for the country, the BBC Weather team forecast for Wednesday (May 15) reads: "Today, cloud and showery rain will affect eastern and central England as well as parts of south-west Scotland and Northern Ireland.

"Sunnier elsewhere with a few early showers in the south-west." Looking ahead at Wednesday evening, it adds: "Tonight, central and eastern parts of the UK will see largely cloudy skies and spells of rain, some occasionally heavy later on; patchy fog in places too. Clearer skies in the south and north."

"Tomorrow, low cloud and showery rain will move across central England and northern Wales with the risk of thunder. Showers for Northern Ireland at times. Elsewhere, mostly sunny conditions," it continues. Its early outlook for the coming weekend explains: "On Friday, central and western parts of the UK will see cloudy skies and showers.

"These could be thundery for many. Elsewhere, it will be largely dry and sunny with a few patches of cloud and the odd shower. Scattered thundery showers in the south on Saturday. Plenty of sunshine elsewhere. Sunny in the south on Sunday, but cloudier with some drizzle further north."