Greece is bracing for its second major heatwave of the summer as a “heat dome” phenomenon moves eastward from Western Europe, bringing temperatures that could exceed 40 degrees Celsius (104 Fahrenheit), beginning Sunday.

The heat dome, characterized by warm air masses that remain stationary due to strong anticyclonic pressures, will approach from the west rather than being fed by hot air masses from Africa, as occurred in Western Europe in recent days.

“‘Heat dome’ is an expression used to emphasize known meteorological phenomena. We saw it in Western Europe in recent days. There was an invasion of warm air masses from Africa, which, due to strong anticyclonic pressures, remained stationary. The warm air remains stationary, heating the entire area, while pressure heats the air even lower,” explained Kostas Lagouvardos, scientific director of meteo.gr.

Temperatures in eastern mainland areas, including the plain of Thessaly, Central Greece, the Peloponnese, Attica and Athens, will exceed 40 degrees Celsius, potentially reaching 41-42 degrees Celsius from Monday. The Cyclades and northern Crete will experience milder temperatures.

Unlike the Western European heatwave that lasted about three days with temperatures exceeding normal levels by up to 10 degrees, Greece expects temperatures 5-6 degrees above normal. “Even so, the thermal burden will be great for public health, the heatwave requires attention for vulnerable people and all of us, especially in cities, where temperatures rise significantly and mainly do not fall much at night, causing discomfort,” Lagouvardos said.

The heat dome will bring normal seasonal northern winds rather than African air masses. “This can lead to high temperatures in Athens and the southern suburbs,” noted the observatory research director.