Heat dome brings record temperatures across Europe

Millions of people across Europe are dealing with extreme heat this week as a weather system meteorologists call a heat dome settles over the continent.

A heat dome forms when high-pressure air stalls over a region. The system acts as a lid, trapping warm air close to the ground and preventing it from rising and dispersing. As the trapped air compresses, it warms further, creating temperatures well above normal for the time of year.

Meteorologists track the jet stream, a fast-moving river of air high in the atmosphere that typically pushes weather systems across continents. When the jet stream moves into a wavy pattern, high-pressure systems can remain stationary over one area for days or weeks. This stalling allows heat to accumulate and intensify.

The trapped air also suppresses cloud formation. Clouds normally reflect sunlight back to space, but without them, more solar radiation reaches the ground and heats the surface further. The effect becomes self-reinforcing: the warmer ground heats the air above it, which strengthens the high-pressure system overhead.

European weather agencies have monitored the dome's development throughout the week. The system brought temperatures significantly above seasonal averages across multiple countries, affecting daily life for residents unaccustomed to such conditions early in the season.

Heat domes can last from several days to several weeks, depending on the strength and position of the jet stream. The pattern may persist until the jet stream shifts back to a more typical configuration, allowing the high-pressure system to move away from the region.

Scientists continue studying whether climate change is altering the frequency or intensity of heat domes. Some research suggests warming oceans and changing atmospheric patterns may allow high-pressure systems to stall more often, though meteorologists emphasize that individual heat events result from complex atmospheric interactions.