The United Kingdom may experience another heatwave in September, as computer forecast models indicate a potential establishment of high pressure over the southern part of the country. This pattern typically leads to dry and predominantly sunny weather, with the possibility of drawing warmth from continental Europe to boost temperatures.
The prospect of warmer weather comes as parts of the UK continue to grapple with significant drought conditions. July was the driest on record for England and Wales, with more than two-thirds of England and all of Wales currently experiencing drought. When soil is very dry, air temperatures can rise more rapidly because energy is not lost to evaporating soil moisture and is instead directed into heating the air.
While some rain is expected this week, it is not anticipated to be sufficient to fully saturate the soil or alleviate the drought situation. Adding to the elevated temperatures is the marine heat affecting the seas around England and Wales, which are currently up to 3 degrees Celsius above average. This oceanic warmth can also contribute to higher land temperatures. All these factors combined increase the likelihood of hotter spells affecting the UK.
Some long-range forecasts are suggesting that the autumn season could be hotter and drier than average. The confluence of high pressure, dry soil conditions, and unusually warm sea temperatures creates a scenario that could favor prolonged periods of elevated temperatures in the coming weeks.