Thunderstorm warnings issued as temperatures hit 30°C in southeast England

The beginning of meteorological autumn has been warm and muggy for many, with temperatures reaching 30°C in southeast England. The heat and humidity sparked lively thunderstorms, though many areas remained dry. Heavy showers and longer spells of rain are expected on Monday, with thundery downpours likely. Thunderstorm warnings have been issued for England, east Wales, and eastern Scotland, with up to 40mm of rain possible within an hour and potentially 80mm overall. Localised flooding, frequent lightning, and hail are also possible.

Tuesday will be fresher with further, but lighter, showers. Midweek forecasts suggest mainly dry conditions for northern areas, while southern parts may continue to see showers. Increased heat and humidity in the south could lead to more thunderstorms by the weekend.

The outlook into the following week suggests more settled conditions could become widespread. However, forecasts are uncertain and may change. From mid-month, a mobile westerly wind is likely, bringing wind and rain to northern and western parts, while the south and east may remain drier.

Long-range forecasts in early autumn can be challenging due to influences across the Atlantic. The peak of the Atlantic hurricane season means any developing storms could affect UK weather patterns, though the current outlook is relatively quiet. The US National Hurricane Center is monitoring a low chance of tropical development this week, but it is unlikely to impact UK weather significantly.

The UK is not expected to experience record-breaking conditions like last September when high pressure led to a significant heatwave. Temperatures exceeded 30°C for seven consecutive days, a September record, with 33.5°C recorded on 10 September, the highest temperature of 2023. Since records began, only in 2016, 1954, 1949, and 1919 has the UK’s highest temperature been in September.