Storm Forecast
Valid: Sat 20 Feb 2010 06:00 to Sun 21 Feb 2010 06:00 UTC
Issued: Sat 20 Feb 2010 05:21
Forecaster: VAN DER VELDE
A level 1 was issued for parts of Bosnia, Montenegro and Albania mainly for isolated excessive convective precipitation.
SYNOPSIS
Europe is under the influence of a large depression, centered over the North Sea, with large areas of convection over the Atlantic parts and smaller areas of convection over the Mediterranean. An important trough and cold front passes the Italy/Balkan region causing an episode with rain and thunderstorms. A new Atlantic depression moves into Portugal by the end of the period.
DISCUSSION
...Balkan...
Less than 200 J/kg MLCAPE is predicted near the Balkan coast as the cold front slowly drags over the region. Instability can occur also deeper inland. Several mid level PV maxima cross southern Italy and the level 1 region, providing lifting motion which supports generation of instability and convection, helped by coastal convergence and orographic lifting. While CAPE and thus convective system size, life time and regeneration may be reduced, the persistence could locally yield high rain sums. Deep layer shear and low level shear are enhanced, but SREH, while 200 mē/sē, is likely not large enough to support a tornadic threat, but a tornado cannot be ruled out either. The same can be said of western Turkey in the region of CAPE.
...Portugal...
A sloping warm frontal surface causes impressive 0-3 km SREH values of 500-1000 mē/sē as the system moves over the western Iberian peninsula late in the period (morning hours). Some elevated convection is possible, followed by surface-based convection behind the occlusion at sea level. There is some overlap in GFS of LLS and DLS fields with CAPE, but SREH is reduced in the overlap zone. This reduces the chance of mesocyclonic storms and tornadoes, although they cannot be ruled out.
