Storm Forecast
Valid: Wed 16 Aug 2006 06:00 to Thu 17 Aug 2006 06:00 UTC
Issued: Tue 15 Aug 2006 23:23
Forecaster: GATZEN

SYNOPSIS

Well developed long-wave trough from Scandinavia to Bay of Biscay ... yielding a very strong south-westerly flow over western Mediterranean, southwestern Europe, and central Europe/Alpine region. Embedded vort-maxima travel northeastward with the main flow ... providing DCVA. At lower levels ... warm and well-mixed desert air mass advects into western Mediterranean ... while subtropical airmass advects into Alpine region and south-eastern Europe. This air mass is characterized by relatively poor boundary layer moisture and lapse rates ... yielding weak CAPE as indicated by latest soundings over northern Mediterranean. Rich low-level moisture is present over western Mediterranean ... that is advected northeastward into southern France during the period. Another interesting region will be northeastern Europe ... where intense short-wave trough travels northward over northwestern Russia.


DISCUSSION

Western Europe

East of the long-wave trough ... strong upper flow os present over most of western Europe. Strong jet streak are embedded in the upper flow and enter central Europe/Mediterranean during the period. WAA is also expected ... and due to DCVA QG forcing should be likely in the range of several jet streaks. CAPE is expected to form in the range of various frontal boundyries in the range of the WAA regime during the day. It is not clear where convection will be concentrated ATTM ... but GFS shows rather widespread convective precip between southern France/northern Italy and the coasts of North Sea and Baltic Sea. While vertical wind shear should be quite weak over most of Germany and Benelux ... strong DLS spreads from western Mediterranean to central France, western Alps, northern Italy, and southwestern Germany. It is not ruled out that thunderstorms will organize along vort-maxima/frontal boundayries ... and multicells/bow echoes seems to be rather likely ... with severe wind gusts the main thread. Embedded mesocyclones may produce large hail and possibly tornadoes, but chance seems to be not significantly enhanced.

Northeastern Europe

In the range of propagating short-wave trough ... thunderstorms should go on south of a frontal boundary over northwestern Russia. Enhanced DLS should increase the threat of organized convection ... but threat seems to be rather weak due to stable low levels.