CONVECTIVE FORECAST
VALID 06Z FRI 11/06 - 06Z SAT 12/06 2004
ISSUED: 10/06 21:47Z
FORECASTER: GATZEN

There is a slight risk of severe thunderstorms forecast across SEern Central Europe

General thunderstorms are forecast across Central Europe

General thunderstorms are forecast across NWern and extremely Nern Europe

SYNOPSIS

Relatively strong zonal flow curves around broad Mediterranean upper high. Two short-wave troughs are placed over NWern and NEern Europe moving slowly Eward. East of the NWern trough ... well developed frontal boundary extends from the Iberian Peninsula across France and south-central Germany to Sern Poland. Latest water vapor satellite images indicate the jet over NWern Europe and an embedded jetstreak over Benelux and show that some MCS have formed along the boundary over France, Germany, the Czech Republic and Austria. On Friday ... NWern trough will propagate Eward, pushing warm and unstable airmass south of the boundary to the SE.

DISCUSSION

...SEern Central Europe ...
On Friday ... short-wave trough will move to the North Sea, and strong upper flow will enter Central Europe. At lower levels ... wavy cold front moves southward reaching the Alps and southern France during the day. Over SEern Central Europe ... cyclogenesis is expected along the frontal boundary, as mid-level jet streak is expected to cross southern Poland and northern Romania. GFS model output suggests strong synoptic forcing associated with this feature. Affected airmass will be unstable due to daytime heating and rather moist boundary layer ... latest observations indicate dewpoints in the 18°C range, and CAPE should reach 1500+ J/kg during the day. Convection is expected along the frontal boundary and/or along outflow boundaries of decaying nocturnal convection. Increasing deep layer wind shear should support organized thunderstorms. If well developed cold pool will form during the night over southern Germany ... MCS/bow echo may cross the affected region, reaching Romania in the evening hours. Severe wind gusts will be the main threat. However ... chance of isolated large hail and tornadoes is enhanced if rotating updrafts form along the leading edge of the MCS.

...Southern Central Europe ...
Latest satellite images show widespread thunderstorms/MCS over southern Central Europe. It is expected that well developed cold pool will form during the night. On Friday ... deep convection will be possible along the Alps and over southern France. Vertical wind shear will be moderate ... and storms may organize into multicells with an enhanced chance of large hail and severe wind gusts.

...Poland, Czech Republic ...
Rather warm airmass over eastern Central Europe should destabilize during the day, and thunderstorms are expected. Given 20 m/s deep layer wind shear, storms may organize. North of developing surface low over SEern Europe ... low level wind shear may be sufficient for mesocyclones. If supercells may form, isolated large hail, damaging wind gusts and a tornado or two should occur.

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