On 18 May, a short-wave trough approached Germany from the west. The associated cold front extended from the UK to Switzerland.
24 May 2022
18 May 2002
At the same time, a cut-off process took place over the Gulf of Lion leading to a separate surface low in the area west of Corsica. This led to an intensification of warm air advection towards the central and eastern parts of the Alps.
In the afternoon, the warm air tongue over the Alps and Southern Germany was the location where severe convection took place. The first pre-frontal convective cells developed in the area of Lake Constance, merging quickly to form a Mesoscale Convective System (MCS). Later in the afternoon, this MCS, fed by inflowing warm air from the east, moved along the Northern slope of the Alps towards Munich where it arrived around 22:00 UTC in the evening.
The system led to severe thunderstorms over Bavaria with hail and torrential rain resulting in flooding and a landslide. Lightning was particularly spectacular and several fires were reported.
The Meteosat-6 rapid scan sequences below show the development of the convective cells during the afternoon of 18 May.