Storm Forecast
Valid: Thu 02 Dec 2010 06:00 to Fri 03 Dec 2010 06:00 UTC
Issued: Wed 01 Dec 2010 15:00
Forecaster: GATZEN

A level 1 is issued for western Albania and north-western Greece mainly for tornadoes.

SYNOPSIS

A long-wave trough that is filled with cold polar air encompasses most of Europe. It yields a strong mid-level jet from northern Africa to the east Mediterranean and the Black Sea. At the surface, a frontal boundary is expected to extend from south of Italy to Greece and the Black Sea.

DISCUSSION

Western Greece to western Black Sea

Ahead of the long-wave trough, a warm air mass advects northward. This air mass is stable as indicated by latest soundings, although the low-level moisture exceeds a mixing ratio of 10g/kg. On Thursday, the mid-level trough will not move eastwards, and mid-levels are not expected to cool strongly. As a consequence, only weak instability is forecast that may also be capped. The best chances for initiation are forecast along the north-western coasts of Greece and western Albania, where upslope flow could overlap with upward vertical motion along the frontal boundary and some mid-level forcing near the jet stream axis. Although strong low-level vertical wind shear is forecast, the weak instability is expected to limit the potential of organized storms. A tornado is not ruled out given the strong low-level vertical wind shear.

West/north Mediterranean

Steep lapse rates are forecast over the warm sea surface as the cold air spreads over the Mediterranean Sea. Weak instability is forecast that will likely cluster to bands parallel to the flow. Given the low-level buoyancy, some waterspouts may develop. Intense convection is not expected.