CONVECTIVE FORECAST
VALID 06Z MON 21/04 - 06Z TUE 22/04 2003
ISSUED: 20/04 22:00Z
FORECASTER: GROENEMEIJER

GENERAL THUNDERSTORMS ARE FORECAST ACROSS PARTS OF THE BRITISH ISLES, THE RHINE LOWLAND, THE ALPS, THE MASSIF CENTRAL, THE PYRENEES, PARTS OF CENTRAL AND SOUTHWESTERN IBERIA, MUCH OF ITALY AND THE WESTERN BALKANS, THE NORTHERN UKRAINE, SOUTHERN BELARUS AND A PART OF RUSSIA.

SYNOPSIS

AN UPPER HIGH IS LOCATED OVER SCANDINAVIA AND A LOW OVER SOUTHERN BRITAIN. A NEUTRAL TO SLIGHT UNSTABLE AIR MASS IS PRESEN NEAR AND JUST EAST OF THE LOW. A MODERATE WESTERLY FLOW IS PRESENT OVER THE MEDITERRANEAN. AN EMBEDDED SHORTWAVE... OVER THE THE GULF OF GENUA AT THE BEGINNING OF THE FORECAST PERIOD...WILL MOVE EASTWARD. THE AIR MASS IS SLIGHTLY UNSTABLE. A TROUGH APPROACHES IBERIA FROM THE WEST AT THE END OF THE FORECAST PERIOD.

DISCUSSION

...BENELUX..BRITISH ISLES..NORTHERN FRANCE...
AS THE LOW IS EXPECTED TO MOVE NORTHWARD SOME STORMS ARE EXPECTED TO FORM BOTH NEAR THE LEADING EDGE OF THE HIGH THETA-E REGIME /WARM FRONT/ MOVING NORTHWARD OVER BRITIAN AND NEAR AWEAK COLD FRONT OVER THE BENELUX AND NORTHERN FRANCE.

...ITALY..WESTERN BALKANS...
ORGANISED CONVECTION WILL BE ONGOING OVER NORTHERN ITALY AT THE BEGINNING OF THE PERIOD. HOWEVER, GIVEN MARGINAL INSTABILITY AND ONLY MODERATE WIND SHEAR...SEVERE THREAT SEEMS QUITE LOW ATTM. OTHER AREA OF CONVECTION OVER SOUTHWESTERN ITALY/SICILY TAKES PLACE IN A MORE STRONGLY SHEARED ENVIRONMENT, BUT IS ELEVATED AND IS DRIVEN BY EITHER LOW CONVECTIVE INSTABILTY OR SYMMETRIC INSTABILITY. THEREFORE, SEVERE THREAT SEEMS LOW WITH THIS ACTIVITY AS WELL.

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