Storm Forecast
Valid: Tue 13 Feb 2007 06:00 to Wed 14 Feb 2007 06:00 UTC
Issued: Tue 13 Feb 2007 09:15
Forecaster: VAN DER VELDE

SYNOPSIS

Meandering westerly 500 hPa flow with lows near the southern Balkan, Poland and an approaching Atlantic trough. Thunderstorms are forecast mostly around the Balkan, Italy and Turkey behind the cold front. Some remaining instability may yield sporadic thunder over northern Germany. GFS indicates some signals of instability along the frontal zone reaching Portugal during the night, in a good shear environment for tornadic activity, but convection may be mostly elevated (weak low level instability signals) and deep lifting not very strong.

DISCUSSION

A mid level vorticity maximum is moving from Italy to western Turkey. Ahead of and below this feature most convection is forecast to occur, while the cold front itself may sometimes be convective as well, with GFS indicating potential instability in the frontal zone. Deep layer shear will be mostly moderate where it overlaps with convection (up to 20 m/s) and low level shear is enhanced mostly by friction over land areas, where instability will usually be less today. 0-3 km SREH is similarly enhanced over land, but in the case of western Turkey (later in the period) GFS indicates some overlap with CAPE.
We may expect one or a few isolated tornadoes (and waterspouts, also outside the level 1 region), and perhaps a few marginally large hail events.