Valid: Fri 22 Apr 2016 06:00 to Sat 23 Apr 2016 06:00 UTC
Issued: Thu 21 Apr 2016 11:06
...SYNOPSIS and DISCUSSION ...
A broad cyclonic vortex over N/NE Europe steers numerous short-waves over CNTRL Europe to the east. An upper trough over the Bay of Biscay moves slowly east while weakening. A subtropical jet affects the SW/S-Mediterranean. Embedded short-waves also induce a localized thunderstorm risk.
Regarding severe probabilities, there is not much to talk about. Roughly 400-700 J/kg weakly capped MLCAPE exists over France and N-Spain. Some overlap of 15 m/s DLS with
CAPE occurs over N-Spain, but nothing more than a few marginally organized thunderstorms with graupel and gusty winds to expect. Over France, DLS of less than 10 m/s assists in disorganized convection. Enhanced LL CAPE could result in an isolated funnel report ... not enough for a level 1.
A similar risk exists over N-CNTRL Italy with marginal hail and gusty winds.
Belarus will see an overlap of 500 J/kg weakly capped MLCAPE with somewhat stronger DLS (in excess of 20 m/s). However, best synoptic-scale forcing will exit the area to the east before diurnal driven diabatic heating will support better CAPE around noon/afternoon. Hence expect scattered thunderstorms with graupel and gusty winds. Good LL CAPE and some SHR-1 may induce a low-end tornado threat during peak heating.
The primary focus for more organized convection will be an eastbound moving cold front, crossing SE Belarus/NW Ukraine before noon from W to E. 15-20 m/s 0-3 km shear may
support a few severe wind gust events, but uncertainties exist how deep convection will grow (warm EL temperatures forecast). Hence no level 1 was issued for now.