After an unseasonable start to the month with heavy bursts of rain and cooler than average temperatures, the jet stream has finally shifted northwards, allowing high pressure to build across the British Isles.
This has enabled more settled conditions to take hold, and delivered some long overdue heat last weekend and through the first half of this week.
Over the weekend, temperatures across the Vale soared into the low-30s Celsius, with all four UK countries recording their highest temperatures of 2021 so far on Saturday. Ballywatticock in Northern Ireland reached 31.2C, making it the hottest day ever recorded in the country, beating the previous record of 30.8C from both 1976 and 1983.
Saturday was also the first 30C day of the year so far, which is relatively late in the year compared to previous summers. Meanwhile, temperatures reached to 30C more widely across England on Sunday, with a maximum of 31.6C at Heathrow, followed by a further few days of intense heat, triggering a few potent afternoon thunderstorms.
The term ‘heatwave’, however, is ambiguous and still very much up for debate amongst meteorologists, as there is no exact quantitative description. For example, the WMO (World
Meteorological Organization) define a heatwave as five consecutive days with daily maximum temperatures five or more degrees above average, whilst the Met Office refer to it as three
consecutive days of temperatures exceeding certain thresholds identified for a given region.
It should remain hot over the next few days, but thunderstorms should ease. High pressure looks to fade over the weekend, as low pressure is expected to push outbreaks of showers and
thunderstorms across the UK from the south. Temperatures will fall nearer to normal, although it will remain rather humid.