The United Kingdom is currently experiencing another heatwave, with forecasters predicting highs of up to 34°C in certain regions. This intense heat is attributed to an expanding plume of warm air originating from continental Europe, which is moving northward and affecting southern and eastern parts of the UK.
According to the Met Office, the country is positioned between two distinct air masses. While warm air drifts north from Europe, low pressure systems are bringing cloud, rain, and cooler air to the northwest. This creates a sharp contrast, a phenomenon known as a baroclinic zone, or boundary between warm and cool air, across or near the UK. Weather fronts are expected to develop along this boundary, bringing slow-moving rain, particularly to northern and western areas.
The warm air mass in the southeast is influenced by a significant high-pressure system over continental Europe. This high pressure encourages widespread sinking air, which suppresses cloud formation, allows for prolonged sunshine, and contributes to rising temperatures through compressional heating. Consequently, temperatures are expected to increase in southern and eastern areas over the next few days, potentially reaching into the low 30s Celsius by Monday.
As the weekend progresses, the influence of the European high pressure is anticipated to extend further north. This shift is expected to bring more settled, drier conditions to many northern parts of the UK, accompanied by rising temperatures and increased sunshine.
However, the rising temperatures also bring an increased risk of humidity and thunderstorms, especially in eastern England. The Met Office has warned that if thunderstorms occur, they could be locally intense, featuring heavy downpours, strong gusts, and frequent lightning, though their exact timing and location remain uncertain.
This heatwave follows recent warnings from experts that extreme heat is becoming a more regular occurrence in Britain. Professor Andrew Charlton-Perez, a professor of meteorology at the University of Reading, noted a shift in perception, where temperatures previously considered warm, such as 27 or 28 degrees Celsius, no longer feel exceptional in the southeast. He added that the likelihood of such temperatures has approximately doubled since the latter decades of the 20th century.
Given the significant impacts of hot weather on vulnerable individuals, the UK Health Security Agency (UKHSA) has advised the public to pay attention to their warnings and take precautionary measures to prepare themselves and others.