Storm Forecast
Valid: Tue 04 Apr 2017 06:00 to Wed 05 Apr 2017 06:00 UTC
Issued: Mon 03 Apr 2017 21:26
Forecaster: DAFIS

A level 1 was issued for parts of Central Europe mainly for large amounts of small hail, tornadoes and severe wind gusts.

A level 1 was issued for parts of SW Greece mainly for large amounts of small hail and severe wind gusts.


SYNOPSIS

A very actvive weather pattern is expected over the European domain during Tuesday. The main feature will be cut-off low system over the Mediterranean Sea which gradually loses its structure, but still cold mid-levels create steep lapse rates and we expect several thunderstorms, driven by diurnal heating. Two short-wave troughs will cross over Germany and France providing lift to quite dry air masses, but still able to produce scattered thunderstorms. Finally, a stationary front extenting from Poland towards Ukraine, is expected to be an area of extensive instability. Finally, this pattern seems to continue during Wednesday.


DISCUSSION

..... Central Europe .....

Latest model runs show the development of several hundreds of CAPE in the area highlighted by a level 1, even up to 1200 J/kg MLCAPE in the afternoon. Despite the upsence of a major synoptic lifting mechanism, apart from the stationary front between Poland and Ukraine, diurnal heating will provide the necessary lift and these unstable air masses can produce long-lasting multicells, producing hail and severe wind gusts. Veering winds near the borders of Austria and Hungary increase the potential of strong updrafts, as some hundreds of SREH build-up. An isolated tornado cannot be ruled out. Hail is not expected to exceed 2cm in diameter and large amounts of small hail should be expected in elevated areas. Thunderstorm activity will continue during the night.

.... SW Greece ....

Even though high resolution models produce a low probability of thunderstorm occurrence during the afternoon - night time, the presence of a jet streak (DLS more than 20 m/s) over some hundreds of CAPE and the possibility of strong low level convergence zones, create a favorable environment for every parcel that manages to rise. With steep mid-level lapse rates, parcels could produce hail and severe wind gusts. Weak NCAPE though, excludes the formation of large hail.