Temperatures are to reach up to 30C in parts of the UK on Tuesday, with an official heatwave likely to be recorded in Engeland before thunderstorms arrive in the south-west.
Conditions were forecast to be in the mid-to-high 20s across England and Wales, while Scotland and Noord-Ierland could see temperatures of about 24C to 25C.
Central and eastern England were the likely areas that could experience a maximum of 30C, according to the Met Office, though a meteorologist said they would only “just about make it” in terms of recording an official heatwave.
The UK heatwave threshold is reached when a location records a period of at least three consecutive days of daily maximum temperature levels meeting or exceeding thresholds that vary across the country.
The Met Office also issued a warning of heavy thundery downpours across south-west England and south Wallis op Woensdag.
Greg Dewhurst, a meteorologist, said that low pressure moving in from the south-west on Wednesday would make it “less hot” in parts of Wales and Northern Ireland, but “hot air” would remain in central and eastern England and Skotland, bringing highs of 26C to 29C.
“We often get a warmer spell, particularly early on in September," hy het gesê.
“August was particularly cool … and cloudy, so this spell is the warmest spell of weather since July for the UK.”
The current conditions follow the official end of the meteorological summer on 31 Augustus. September has already exceeded this August’s highest temperature of 27.2C in the UK, which last happened in 2016.
Temperatures forecast for this week are still some way off the record for September heat, which was set in 1906 at 35.6C. Egter, the frequency of temperatures exceeding 30C has been increasing over the last 50 jare.
The Met Office’s yellow warning of thunderstorms for south-west England on Wednesday came with the forecast that 30-50 mm of rain could fall in less than 3 ure. Lightning may also be a hazard during the day.
Maandag, the maximum UK temperature was logged at 28.9C in Larkhill, Wiltshire, closely followed by the 28.8C recorded at Santon Downham, Suffolk, and 28.7C at Middle Wallop in Hampshire.
In Wales, the highest temperature was 27.1C at Usk in Monmouthshire, while the mercury reached 24C at Fyvie Castle in Aberdeenshire, Skotland, and 22.2C at Ballywatticock in Northern Ireland.