CONVECTIVE FORECAST
VALID 06Z SAT 30/10 - 06Z SUN 31/10 2004
ISSUED: 29/10 21:11Z
FORECASTER: DAHL

There is a slight risk of severe thunderstorms forecast across central Mediterranean Sea.

General thunderstorms are forecast across western Europe and the central Mediterranean.

General thunderstorms are forecast across NE Germany and W Poland.

SYNOPSIS

High-amplitude upper pattern persisting through this period ... with large-scale W-European upper trough progged to close off into an upper cut-off low late in the period ... and strong ridging over the central Mediterranean ... spreading across SE and E-central Europe by Sunday early morning. At low levels ... plume of warm air mass is spreading northwards E of W-European upper trough ... with a frontal wave moving across E-central Europe ahead of peripheral upper vort max. Cyclogenesis also expected over the WRN Mediterranean ahead of developing cut-off low late on Saturday.

DISCUSSION

...central Mediterranean...
It looks that main threat for potentially severe convective storms will exist over the central Mediterranean regions ahead of vigorous vort max. 850 hPa theta-e fields indicate that plume of EML will be advected northwards E of the developing SFC low ... which should strengthen CAPE so that 1000+ J/kg MLCAPE should develop over the central Mediterranean during the afternoon/evening hours.

20 to 25 m/s deep-layer shear ... and 10 to 12 m/s 0-1 km shear should provide kinematic environment allowing for severe TSTMS ... with severe straight-line winds ... large hail and possibly a few tornadoes.

...western Europe and the central Europe including SEE TEXT area...
Deep ... mixed polar air will be present over much of W and central Europe. Best chances for showers and scattered TSTMS should exist ahead of the various vort maxima revolving around the main trough. Also ... a few TSTMS could develop along the cold front of the wave cyclone over NE Germany/Poland ... as hinted at by NMM and GFS somutions. This convection should be strongly sheared and could briefly promote severe TSTMS ... but confidence in TSTM development along the front remains rather limited ATTM.

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