CONVECTIVE FORECAST
VALID 06Z MON 10/05 - 06Z TUE 11/05 2004
ISSUED: 10/05 00:22Z
FORECASTER: GROENEMEIJER

General thunderstorms are forecast across the British Isles, large parts of western, central and eastern Europe, southern Scandinavia and across southern Finland and eastern parts of Italy.

SYNOPSIS

Monday at 06 Z... downstream of a stationary ridge over the eastern Atlantic, warm and unstable air-mass over Scandinvia is slowly flowing southward into western and central Europe. An mid and upper-level low presure systems is located over southern Portugal. A NE-SW oriented trough from near the Baltic States tothe northern Balkans is lifting northeastward.

DISCUSSION

...UK, parts of Ireland, the Low countries and northern and central Germany...
A weak warm front will we working its way southward and southwesterward into the British Isles, the Benelux and France, central Germany and northern Poland. Steep lapse rates observed over southern Scandinavia are expected to advect southward into the area. Low-level moisture and solar heating will likely be adequate to produce 400 - 800 J/kg MLCAPE over northern and Germany and a few 100's of J/kg MLCAPE over the British Isles. Scattered thunderstorms are expected to form in the region. Near the warm front and over the British Isles LCL heights will likely be rather low, and low level lapse rates quite steep, so that a few weak tornadoes could be possible in the indicated area. Some thunderstorms will likely produce hail that could exceed the limit of 2 cm diameter locally. Severe events are expected to be so isolated that a risk category is not warranted at the moment. However, an update may be needed when more instability than currently expected materializes.

...Eastern Balkans. northwestern Turkey...
A few 100's of J/kg MLCAPE should be able to form in this region, where about 15 - 20 m/s 0-6 km shear is forecast as a weak mid/upper jet overspread the area from the northwest. Expect a few multicell storms, locally capable of producing hail around the severe limit of 2 cm.

...eastern Ukraine...
North of the Krim peninsula, renewed destabilisation of the air-mass is expected. A few 100's of J/kg MLCAPE should be able to form. Moderately strong deep-layer shear indicates the possibility of a few better organised multicell storms, that could produce hail marginally larger than 2 cm.

#