CONVECTIVE FORECAST - UPDATE
VALID 12Z FRI 30/07 - 06Z SAT 31/07 2004
ISSUED: 30/07 11:33Z
FORECASTER: GATZEN

General thunderstorms are forecast across Benelux and NWrn Germany, NWrn Spain, Srn France, Alpine region, central Italy, SErn and Ern Europe

SYNOPSIS

Broad upper ridge present over Europe. Embedded cut-off lows are forecast over the southern North Sea, the Baltic States, the northern Balkans and extremely southern Mediterranean on Friday. At lower levels ... warm airmass will be present south of a line from northwestern France to northern Germany, southern Poland and further to extremely southeastern Scandinavia. Rather cold airmass will remain over the northern Balkans.

DISCUSSION

...Benelux, NWrn Germany...
In the range of the eastward moving cut-off low ... instability is stronger than expected, and thunderstorms have formed over the southern North Sea in the morning hours. During Friday afternoon ... insolation is expected that should lead to sufficient instability as upper troposphere cooling is expected. CAPE should likely reach more than 400 J/kg, and thunderstorms should form in the next hours along a convergence line/outflow boundary over Benelux. At the southern flank of the cut-off low ... deep vertical wind shear will be moderate ... and thunderstorms may organize into small bows and multicells. Mesocyclones are also not ruled out capable of producing isolated large hail/damaging wind gusts. Convective activity should cluster and move eastward, where strong windgusts should be the main threat as low-level airmass is well mixed. During the evening ... thunderstorms may form along eastward moving outflow-boundaries over western/northwestern Germany.

...other areas...
see previous outlook

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