Storm Forecast
Valid: Wed 16 Jan 2008 06:00 to Thu 17 Jan 2008 06:00 UTC
Issued: Tue 15 Jan 2008 22:27
Forecaster: GATZEN

SYNOPSIS

Eastern Europe is covered by high pressure, while sharp upper trough amplifies over west Europe. It shows a tendency to cut off into southern Mediterranean later this week. To the east, a weak westerly flow affects most of the Mediterranean. At the end of the period, a strong westerly jet reaches western Europe. At low levels, air mass is rather stable over most places due to cold and dry boundary-layer air mass. Best potential for thunderstorms exists in the range of the southern trough centers, where steep low-level lapse rates are most likely.

DISCUSSION

Southern Adriatic to Aegean

A weak upper trough slowly propagates eastward into Aegean Sea during the period. In the range of the trough center, low-level air mass is well-mixed. During the period, steep low-level lapse rates will advect eastward into Greece region. Given rather warm water surface, low-level moisture is expected to increase, yielding some CAPE and also showers and thunderstorms. Weak vertical wind shear is expected in the lower levels, and do not expect organized convection. However, a few waterspouts are not ruled out given locally strong low-level buoyancy.

West Mediterranan Sea

Amplifying trough will spread over west Mediterranean. In the range of the trough, step lapse rates are present and will likely lead to some instability at the cyclonic flank of an upper jet streak moving into Iberian Peninsula during the day. QG forcing will be present and thunderstorms are forecast to develop. While most convection will likely be unorganized, chance for some stronger cells increases to the south, where vertical wind shear will be stronger. Given strong low-level buoyancy, one or two tornadoes and isolated severe wind gusts are not ruled out.

Southern British Isles, northern France

A strong upper jet reaches this region at the end of the period, and strong QG forcing will affect a tongue of very moist maritime air mass advecting eastward south of the low pressure center. Models do not agree well about the position and amount of developing instability, but given strong vertical wind shear, potential for severe thunderstorms is rather high. An upgrade may be needed during the period. Current thinking is that embedded thunderstorms will form indeed, capable of producing high winds and maybe a few tornadoes. However, later indications have to prove the level 1 region.