Highlight: Explaining what caused the Western Europe Dust Storm.
Fig. 1: Upper air pattern across Europe for March 15, 2022.
The past couple days brought a northward surge of dust from the Sahara Desert to Southwest Europe reaching U.K. Dust storms over Southwest Europe are not unusual this time of year. However, the northern expanse and intensity of this event was exceptional. The northern surge of Sahara Dust was caused by a strong low-level southerly current of air across Northwest Africa in-between a small but potent upper trough on the Northwest Coast of Africa and an amplified upper ridge pattern over Northern Europe (Fig. 1). The pattern is characteristic of the positive phase of the Scandinavia Index (+SCAND) regime.
The upper-level pattern causing the dust storm was induced by the North America climate regime featuring an aggressive upper trough extending to the North-Central U.S. from the polar vortex over Northeast Canada and eastward across the Northern Atlantic (Fig. 2). In recent days, the upper trough has strengthened over Southern Greenland and emitted shortwave energy which cutoff on the Northwest Africa Coast to cause the dust storm. Compensating for the strong upper trough across Canada to Greenland is the amplifying upper ridge over Northwest Eurasia acting as a blocking pattern which forces upper-level energy southeastward toward Northwest Africa (from Greenland). The pattern described is also responsible for the compensating cold upper trough over Ukraine/Black Sea region to Central Russia. Although this event took place in Europe, the triggers were born in North America.
Fig. 2: Prevailing FEB/MAR 2022 upper air pattern across North America to Europe.