CONVECTIVE FORECAST - UPDATE
VALID 11Z MON 19/05 - 06Z TUE 20/05 2003
ISSUED: 19/05 11:52Z
FORECASTER: GROENEMEIJER

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF FRANCE, GERMANY, SWITZERLAND, AUSTRIA AND THE CZECH REPUBLIC

GENERAL THUNDERSTORMS ARE FORECAST ACROSS THE BRITISH ISLES, THE BENELUX COUNTRIES, SOUTHERN SCANDINAVIA, MUCH OF FRANCE, IBERIA AND CENTRAL EUROPE. PARTS OF WESTERN RUSSIA, THE BALTIC STATES, THE WESTERN UKRAINE AND BELARUS AS WELL AS THE CENTRAL AND EASTERN BALKANS AND PARTS OF TURKEY.

SYNOPSIS

SEE PREVIOUS BULLETIN FOR DISCUSSIONS OF "SEE TEXT" AREAS AND SYNOPSIS

DISCUSSION

...SLIGHT RISK AREA...
FRONTAL WAVE OVER BELGIUM AT 11Z WILL MOVE NORTHEASTWARD. A POORLY DEFINED COLD FRONT APPEARS TO BE LOCATED NEAR A LINE FROM GHENT TO CLERMONT-FERRAND. AHEAD OF THE FRONTAL ZONE SURFACE WINDS HAVE BACKED TO SOUTHERLY DIRECTIONS OVER MUCH OF EAST-CENTRAL FRANCE AND SOUTHWESTERN GERMANY. AMOUNT OF LOW-LEVEL SHEAR SEEMS TO BE HIGHER THAN GFS AND MM5 GIVEN MEASURED 45 KT 0-1 KM SHR AT STUTTGART (00Z), KUEMMERSBRUCK (06Z) AND 30 KT AT PAYERNE (06Z). DEEP CONVECTION SEEMS TO BE ABOUT TO INITIATE OVER PARTS OF SOUTHCENTRAL AND EASTERN FRANCE AHEAD OF AND NEAR THE COLD FRONT. SOME OF THE STORMS MAY ALSO BE ACCOMPANIED BY LARGE HAIL AND LOCALLY SEVERE WIND GUSTS. MORE CONVECTION IS EXPECTED TO INITIATE FURTHER EASTWARD OVER SOUTHER GERMANY AND SWITZERLAND LATER TODAY AND INTO THE EVENING. SOME CONVECTION WILL LIKELY BE SUPERCELLULAR, QUITE RAPIDLY ORGANISING INTO ONE OR MORE LINEAR CONVECTIVE SYSTEMS, POSSIBLY STILL HAVING EMBEDDED MESOCYCLONES. GIVEN QUITE LOW LCL HEIGHTS, AND MODERATE TO STRONG LOW-LEVEL (DIRECTIONAL) SHEAR IN PLACE, ONE OR TWO TORNADOES MAY OCCUR, ESPECIALLY OVER THE AREA OF THE VOSGES MOUNTAINS, THE JURA, UPPER-RHINE VALLEY AND BADEN-WURTTEMBERG. FURTHER EAST...LOW LEVEL SHEAR WILL BE LESS AND THREATS WILL BE LIMITED TO HAIL AND WIND GUSTS.

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