Mesoscale Discussion
Valid: Wed 02 May 2018 18:00 to Thu 03 May 2018 06:00 UTC
Issued: Wed 02 May 2018 18:13
Forecaster: PISTOTNIK

This MD is issued to highlight an enhanced severe storm risk over east-central Europe.

Thunderstorm activity has rapidly increased over the last couple of hours near the nose of the warm air advection regime. 12z soundings from Zagreb and Vienna characterize the environment with CAPE around 700 J/Kg, 0-3 km shear around 15 m/s and low-level veering. Radar loops confirm organized storms, including a number of splitting supercells. Large hail has multiply been reported with maximum documented hailstone sizes of 2-4 cm in E Austria and up to 6 cm in E Slovenia.
Storms are increasingly clustering along the diffuse warm front / convergence zone and moving almost parallel to it from S to N. The hail risk will gradually decrease, while dangerous flash floods become an increasing concern, especially over the hilly terrain of the eastern Alps. In addition, an enormous amount of lightning occurs with these storms.
Activity will likely stay vivid until midnight and will gradually decrease afterwards.