Storm Forecast
Valid: Sat 23 Apr 2016 06:00 to Sun 24 Apr 2016 06:00 UTC
Issued: Sat 23 Apr 2016 05:50
Forecaster: TASZAREK

A level 1 was issued for parts of N Spain mainly for severe wind gusts and in lesser extent for large hail.

SYNOPSIS and DISCUSSION

An advection of cold arctic air mass trough North Sea and Scandinavia into N and part of CNTRL Europe begins. Within this advection a low-topped convection will develop over marine areas and occasionally may produce lightning. Steep lapse rates that will develop over Sweden, and parts of NE Europe will pose the same treat as well. However, a poor moisture content may be a limiting factor for any lightning occurrence, thus instead of 15% lightning prob. the real threat may drop to around 5%. A second area where a widespread development of convection is expected covers most of the S Europe that lies under moist and weakly unstable polar air mass. Within the lowering pressure, an uncapped CAPE of 200-600 J/kg extends from N Portugal up to Romania, S of the main jet streak stretching from S Portugal up to Greece. Thus, the vast majority of thunderstorms remains in a weakly sheared environment where a severe convective phenomena will be unlikely. The small overlap of ~200-400 J/kg CAPE with ~ 20-30 m/s DLS includes part of N Spain where a weakly pronounced short wave will pass this area in the afternoon hours. Cells that will originate in this environment may evolve into low-topped supercells creating a local threat for severe wind gusts. Large hail within this storms cannot be ruled out. However, due to rather poor moisture and weak instability, the threat is rather low and covers hail up to 2-3cm. In the end of the forecast hours, a persistent DMC is expected to originate over NE Greece, and continue to develop during the next day.