Storm Forecast
Valid: Wed 15 Nov 2006 06:00 to Thu 16 Nov 2006 06:00 UTC
Issued: Tue 14 Nov 2006 21:54
Forecaster: GATZEN

SYNOPSIS/DISCUSSION

Broad upper ridge over Europe covers Mediterranean, central Europe, and Balkans. Warm air mass is present in the range of this high. Soundings indicate a huge inversion over Mediterranean, while thermodynamic profiles are nearly moist-adiabatic near the frontal boundary over northern Europe. A strong westerly jet extends from British Isles to southern Scandinavia and further to Black Sea. To the north of the frontal boundary, cold maritime air mass is slightly unstable, but instability is restricted to lower levels mostly.

Best chance for isolated thunderstorms seem to exist north of a strong jet streak that moves eastward over central Baltic Sea, where latest model output suggests negative LI during the period. However, it seems that warm air advection and associated forcing will support stratiform precipitation in this region, and thunderstorms seem to be not likely.

Another focus of local thunderstorm development is Portugal, where cold front approaches during the period. Given some CAPE and forcing along the cold front, thunderstorms are expected to move into Portugal during the afternoon hours, spreading north-eastward. Given south-westerly winds at all levels and weak vertical wind shear, organization of convective cells seem to be unlikely and severe thunderstorms are not forecast.

Third focus of convective activity may be southern France. Strong low-level southerly winds associated with warm air advection are expected, resulting in strong moisture transport from Mediterranean Sea to southern France. Upslope flow and low-level convergence may lead to local initiation of showers and thunderstorms. Weak CAPE and vertical wind shear will not support organized convection.