Storm Forecast
Valid: Thu 13 Mar 2008 06:00 to Fri 14 Mar 2008 06:00 UTC
Issued: Wed 12 Mar 2008 22:46
Forecaster: GATZEN

SYNOPSIS

Intense upper trough has moved to southern Scandinavia, while subtropical ridge is present over Iberian Peninsula. A strong upper jet stream is located from British Isles to Germany, Balkans, and Turkey during the period. At lower levels, relatively cold air mass has spread into central Europe and Balkan region, while better low-level moisture is remaining from Black Sea region to Belarus. Warm air mass is also advecting into south-western Europe.

DISCUSSION

Belarus

At the eastern flank of propagating short-wave trough present to the north-east of the strong upper jet stream, a southerly jet streak is expected to develop over Ukraine during the period. At is spreads northward ahead of the negatively tilted trough axis, quite strong DCVA is expected over Belarus. At low levels, a cold front will cross Belarus in the morning hours. To the west of this frontal boundary, quite moist air mass will be present as indicated b latest model data. Given strong QG forcing and increasing lapse rates, at least weak instability may develop. Showers and thunderstorms are forecast. Given moderate deep layer vertical wind shear, well-organized multicells or mesoclones are forecast, capable of producing isolated large hail and severe wind gusts. Chance for tornadoes is very limited given dry low-level air mass and only moderate low-level vertical wind shear. Given weak instability, convective development is quite questionable, and a level 1 seems to be not necessary at this time.

Turkey

Weakening cold front will reach Turkey during the period. Associated trough axis will likely lead to QG forcing and increasing lapse rates. Showers and thunderstorms are forecast. Given rather weak vertical wind shear in the range of the upper trough axis, convection is forecast to be unorganized. Isolated waterspouts may be possible along the coasts.

North Sea to central Balkans

Just north of the strong jet streak, a well-mixed maritime air mass is expected that will likely destabilize during the day. Given some QG forcing and low-level convergence, some showers and thunderstorms are forecast. Given strong low-level vertical wind shear, some cells may rotate. Given relatively poor low-level moisture, chance for isolated tornadoes is limited, but will not rule out n isolated event at this time.