Valid: Sat 17 Dec 2011 06:00 to Sun 18 Dec 2011 06:00 UTC
Issued: Sat 17 Dec 2011 04:37
Forecaster: VAN DER VELDE
SYNOPSIS and DISCUSSION
Cold maritime airmass with steep lapse rates between surface and 500 hPa is entering Europe behind a cold front belonging to a depression now over the Baltic Sea. CAPE is highest over sea. Numerous showers with isolated thunder and small hail or graupel can occur around the North Sea, as well as over the northern Mediterranean/Adriatic Sea where more water vapour is available and storms will therefore be more electrified.
Organization of convection, forcing and postfrontal vertical windshear in the lowest kilometers are weak, and while quite strong pressure gradients are still present for strong wind gusts, the threat for organized severe weather from convection is rather low. Waterspouts can occur, in particular along Italian and Balkan coasts where low level lapse rates and buoyancy are maximized,