A crushing heat dome is coming: why experts already fear the worst

An Unstable Start Gives Way to Relentless Heat After a spell of very unstable weather, a high-pressure system (anticyclone) is setting up shop smack dab over France. Its arrival means persistently calm, dry, and gloriously sunny weather across the country. But that’s not all—it’s also locking in heat rising up from North Africa. Thanks to a swirling low pressure and a northbound jet stream (which divides hot southern air from cold northern air) arching over the British Isles, a wave of sizzling air is about to sweep across the nation.

A crushing heat dome is coming: why experts already fear the worst. An Unstable Start Gives Way to Relentless Heat After a spell of very unstable weather, a high-pressure system (anticyclone) is setting up shop smack dab over France. Its arrival means persistently calm, dry, and gloriously sunny weather across the country. But that’s not all—it’s also locking in heat rising up from North Africa. Thanks to a swirling low pressure and a northbound jet stream (which divides hot southern air from cold northern air) arching over the British Isles, a wave of sizzling air is about to sweep across the nation. This Wednesday afternoon (May 20), the mercury had already reached 86°F (30°C) in Aude, Var, and Hérault—about 11 to 14°F (6 to 8°C) warmer than usual for this time of year. Yes, the South of France was practically a beach party by itself. A...