Mesoscale Discussion
Valid: Thu 24 Jun 2021 13:00 to Thu 24 Jun 2021 17:00 UTC
Issued: Thu 24 Jun 2021 13:09
Forecaster: GATZEN

Ahead of an approaching upper-level trough from the south-west, a strong mid-level jet spreads across the Alps. At lower levels, warm air advection has set in across Austria and Czechia. A frontal boundary divides very warm and well-mixed air masses to the south of the Alps and across Hungary and Slovakia from moist and modest warm air to the north-west. North-easterly winds have evolved within the moist air mass with increased vertical wind shear and expected storm-realtive inflow.

Convection initiation is expected within the next hours ahead of a pressure wave or cold front that moves across southern Germany at 12 UTC. These storms will rapidly become supercells in very strong DLS, moving NE. Large or very large hail is expected along with severe wind gusts.

Upscale growth becomes likely as the storm coverage increases as storms move north-east into Czechia and Slovakia, where deeper boundary layer will also be supportive for strong downdrafts. High winds will become a major threat in this area, and foreward propagation will support fast moving bow echoes that are forecast to enter Poland after the validity time of the MD, where a high wind event may evolve in the evening.