VALID 00Z SUN 27/10 - 00Z MON 28/10 2002
ISSUED: 26/10 12:27Z
FORECASTER: GROENEMEIJER

THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN ENGLAND, THE BENELUX COUNTRIES, NORTHERN FRANCE, NORTHERN AND CENTRAL GERMANY, WESTERN POLAND AND WESTERN CZECH REPUBLIC

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS AN AREA SURROUNDING THE MODERATE RISK AREA.

GENERAL THUNDERSTORMS ARE FORECAST ACROSS MUCH OF THE NORWEGIAN SEA, SOUTHERN SCANDINAVIA, MUCH OF NORTHWESTERN CONTINENTAL EUROPE, THE BRITISH ISLES AND ADJACENT PARTS OF THE ATLANTIC OCEAN.

SYNOPSIS

A STRONG ZONAL JET IS PRESENT OVER THE EASTERN ATLANTIC. A STRONG SURFACE CYCLONE NOW LOCATED NEAR 51N 22W IS EXPECTED TO MOVE EASTWARD. A VERY STRONG WIND FIELD IS FORMING ON THE SOUTHWESTERN FLANK OF THE SYSTEM. SOME INSTABILITY IS BUILDING IN THE POLAR AIR MASS WEST OF THE COLD FRONT ASSOCIATED WITH THE SYSTEM.

DISCUSSION

...SOUTHERN ENGLAND, THE BENELUX COUNTRIES, NORTHERN FRANCE, NORTHERN AND CENTRAL GERMANY, WESTERN POLAND AND WESTERN CZECH REPUBLIC...
AFOREMENTIONED STRONG WIND FIELS IS EXPECTED TO AFFECT SOUTHERN ENGLAND AND POSSIBLY SOUTHERN IRELAND AT THE BEGINNING OF THE FORECAST PERIOD. CONVECTION NEAR THE COLD FRONT WILL LIKELY NOT BE SEVERE. VERY HIGH WIND GUSTS ARE EXPECTED IN ASSOCIATION WITH CONVECTION DEVELOPING NEAR SURFACE TROUGH/BACK BENT OCCLUSION FAR BEHIND COLD FRONT. WIND GUSTS WILL LIKELY BE AS HIGH AS 80 KNOTS IN PLACES. STRONG /50 KNOT/ 0-1 LOW-LEVEL WIND SHEAR WILL PROVIDE AN ENVIRONMENT FAVOURABLE FOR THE DEVELOPMENT OF HELICAL INFLOWS NEAR CONVECTIVELY OR OROGRAPHICALLY INDUCED FLOW PERTURBATIONS. THIS MEANS SOME EMBEDDED ROTATION UPDRAFTS ARE POSSIBLE AND SOME CHANCE OF TORNADOES EXISTS. IN ASSOCIATION WITH THESE SOME MARGINALLY SEVERE HAIL MAY BE POSSIBLE. MAIN THREAT HOWEVER WILL BE VERY STRONG GUSTS. IF DEVELOPMENT OF WIND FIELD IS SLIGHTLY MORE AGGRESSIVE THAN CURRENTLY ANTICIPATED A HIGH RISK MAY BE ISSUED IN LATER OUTLOOKS.

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