CONVECTIVE FORECAST
VALID 06Z FRI 23/05 - 06Z SAT 24/05 2003
ISSUED: 22/05 21:12Z
FORECASTER: GATZEN

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS EXTREMELY NORTHEASTERN EUROPE

GENERAL THUNDERSTORMS ARE FORECAST ACROSS PARTS OF EASTERN EUROPE

GENERAL THUNDERSTORMS ARE FORECAST ACROSS EASTERN MEDITERRANEAN

SYNOPSIS

CUT-OFF LOW PLACED OVER EASTERN CENTRAL MEDITERRANEAN. WESTERN EUROPEAN TROUGH AMPLIFIES. UPPER RIDGE EXTENDING FROM WESTERN MEDITERRANEAN TO CENTRAL RUSSIA SEPARATES BOTH TROUGHS. AT THE SURFACE ... FRONTAL BOUNDARY OVER EASTERN CENTRAL EUROPE WILL PROPAGATE EASTWARD NORTH OF 55N.

DISCUSSION

...EXTREMELY NORTHEASTERN EUROPE...
WITHIN MODERATE UPPER SOUTHWESTERLY FLOW ... SHORT-WAVE AFFECTS FRONTAL BOUNDARY BENEATH. AIRMASS SOUTH OF THE COLDFRONT IS QUITE UNSTABLE WITH MUCAPES IN THE ORDER OF 1000 J/KG. SYNOPTIC-SCALE LIFT IS FORECAST NORTHEAST OF THIS WAVE. WITHIN THE DAY ... WITH SUPPORT OF INSOLATION THUNDERSTORMS SHOULD DEVELOP ALONG AND EAST OF THE FRONTAL BOUNDARY ... GIVEN MODERATE VERTICAL WINDSHEAR AND PROBABLY OROGRAPHICALLY ENHANCED SRH ... ISOLATED CELLS SHOULD LIKELY BECOME SUPERCELLS ... WITH A CHANCE OF LARGE HAIL AND DAMAGING WINDGUSTS. ONE OR TWO TORNADOS ARE NOT RULED OUT. GIVEN STRONG LARGE SCALE LIFT, CELLS SHOULD CLUSTER INTO ONE OR TWO MCS WITHIN THE AFTERNOON.

...CENTRAL EASTERN MEDITERRANEAN...
CUT-OFF LOW WITH RELATIVELY COLD MIDLEVEL AIRMASS WILL LEAD TO SOME INSTABILITY. THUNDERSTORMS ARE LIKELY. VERTICAL WINDSHEAR ALONG THE EDGE OF THIS CUT-OFF SHOULD HELP FOR THUNDERSTORM ORGANIZATION. BEST POTENTIAL FOR STRONG STORMS WILL BE ALONG THE EASTERN EDGE OF CUT-OFF ... WHERE RELATIVELY WARM LOW-LEVEL AIRMASS WILL LEAD TO MUCAPE IN THE ORDER OF 700 J/KG. HOWEVER ... LOW-LEVEL WIND-SHEAR DOES NOT SEEM FAVOURABLE FOR SUPERCELLS. GIVEN LOW LCLS AND OROGRAPHIC SUPPORT ... SHORT-LIVING MESOCYCLONES SEEMS TO BE POSSIBLE ... WITH A SLIGHT CHANCE OF WATERSPOUTS AND MARGINALLY HAIL.

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