Storm Forecast
Valid: Sun 16 Nov 2008 06:00 to Mon 17 Nov 2008 06:00 UTC
Issued: Sun 16 Nov 2008 00:34
Forecaster: SCHLENCZEK

SYNOPSIS

Two features dominate the weather pattern in the central parts of Europe: An upper cut-off low over the central Mediterranean translates towards Greece. At 500hPa, a 30 m/s jet streak over northern Libya will travel northeastward with its left exit region over SW Greece. Upstream of a low pressure complex located over the Baltic States, a strong upper trough will overspread the Baltic Sea and Poland during the day. Quiescent conditions will remain over southwestern and southeastern Europe where an upper ridge is present.

DISCUSSION

...Central Mediterranean, Ionian Sea...

Moderate CAPE is in place over the central / eastern Mediterranean in an environment with low to moderate deep layer shear (10 - 20 m/s). As the upper low weakens, QG forcing will be limited but moderate shear may allow some organized multicells. Some of them may develop rotating updrafts and produce isolated large hail / severe gusts. Especially in the western part of the area where shear is rather weak, steep low level lapse rates and low LCL heights should lead to some waterspouts.

...NE Germany, Poland, W Belarus...

A vigorous upper vort max associated with an upper shortwave trough will overspread parts of central / eastern Europe during the afternoon / evening hours. Wind speeds around 20 m/s are present at 850hPa and vertical cross sections hint at potential instability next to the cold front ahead of the trough. Even though instability is very limited and horizontal temperature gradients are rather low, one or two shallow convective lines with sporadic lightning may evolve and downward momentum transport will allow convectively enhanced gusts that exceed the severe threshold. As low level shear is in order of 15 m/s and orographic features may provide significant directional shear, tornadoes are not discounted either. Overall threat should reach the level one threshold.