VALID 09Z FRI 22/11 - 06Z SAT 23/11 2002
ISSUED: 22/11 09:04Z
FORECASTER: HAVEN

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS EXTR S BRITISH ISLES, FRENCH W-COAST, BAY OF BISCAY

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS ADRIATIC SEA AND ADJACENT COASTAL AREAS

GENERAL THUNDERSTORMS ARE FORECAST ACROSS S-GREECE, AEGEAN SEA

SYNOPSIS

UPPER JETSTREAM IS SITUATED OVER IBERIAN PENINSULA AND WRN MEDITERRANEAN WITH UPPER TROUGH OVER ITALY MOVING TOWARDS BALKAN STATES. OTHER UPPER TROUGH OVER S-GREECE CONTINUES EAST. FURTHER UPSTREAM OVER ATLANTIC SEVERAL COLD AIR TROUGHS ARE ROTATING AROUND UPPER LOW WEST OF IRELAND. AT LOWER LEVELS...MARITIME POLAR AIR IS SPREADING OUT OVER CENTRAL EUROPE FROM WEST BEHIND FRONTAL SYSTEM FROM NW-GERMANY TO PO VALLEY TO TUNESIA AT 06Z. SYSTEM WILL MOVE EAST TO ERN EUROPE AND BALKAN STATES DURING THE PERIOD.

DISCUSSION

...EXTR S BRITISH ISLES, FRENCH W-COAST, BAY OF BISCAY...
SLIGHTLY UNSTABLE AIR WITH FEW HUNDRED J/KG CAPE IS AVAILABLE FOR DEVELOPMENT OF SHOWERS AND THUNDERSTORMS, ESPECIALLY NEAR TROUGHS WHICH ARE CLAERLY IDENTIFIABLE IN SATELLITE IMAGERY. DEEP LAYER SHEAR IS SUFFICIENT FOR ORGANIZATION OF STORMS AS CAN BE SEEN IN 06Z SOUNDING OF 03953 (VALENTIA) AND MODEL OUTPUT FURTHER SOUTH, BUT LOW CAPE WILL LIMIT SEVERE THREAT. HOWEVERE WINDGUSTS SLIGHTLY AOVE 50 KTS ARE QUITE POSSIBLE AS SHOWED BY 06Z SURFACE OBSERVATIONS IN NW-FRANCE. ALSO A BRIEF TORNADO CANNOT BE RULED OUT.

...ADRIATIC SEA AND ADJACENT COASTAL AREAS...
LIRE (ROME) SOUNDING OF 06Z SHOWS SLIGHTLY UNSTABLE PROFILE, STRONG VEERING WINDS IN LOWEST KM AND STRONG SHEAR BETWEEN 3 AND 5 KM. SUCH PROFILE IS FAVORABLE FOR LP (MINI) SUPERCELLS, ALTHOUGH NOT MUCH IS KNOWN ABOUT THEIR EUROPEAN CLIMATOLOGY. STORMS THAT FORM MAY BE CAPABLE OF PRODUCING (MARGINAL) LARGE HAIL, SEVERE WINDGUSTS AND FUNNEL CLOUDS/BRIEF TORNADOES, ESPECIALLY IN COASTAL AND MOUNTAIN AREAS WHERE LOW-LEVEL WINDPROFILES ARE MODIFIED.

...S-GREECE, AEGEAN SEA...
CURRENT THUNDERSTORM ACTIVITY WILL MOVE EAST WITH UPPER TROUGH. LOW CAPE/MOD SHEAR ENVIRONMENT WILL KEEP SEVERE THREAT LOW.

#