CONVECTIVE FORECAST
VALID 17Z SAT 10/05 - 06Z SUN 11/05 2003
ISSUED: 10/05 16:29Z
FORECASTER: GATZEN

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN EUROPE

GENERAL THUNDERSTORMS ARE FORECAST ACROSS PARTS OF CENTRAL EUROPE, NORTHERN EUROPE, SOUTHEASTERN EUROPE

SYNOPSIS

BROAD UPPER LONG-WAVE TROUGH SITUATED OVER NORTHEASTERN ATLANTIC. TO THE EAST ... WELL DEFINED UPPER JETSTREAM EXTENDS FROM FRANCE AND BRITISH ISLES TO NORTHWESTERN RUSSIA. WITHIN THIS UPPER JET ... SHALLOW WAVES MIGRATES NORTHEASTWARD. OVER THE WESTERN MEDITERRANEAN ... UPPER SHORT-WAVE TROUGH REFILLS AND DRAGS WESTWARD. AT LOWER LEVELS ... FRONTAL WAVES PROPAGATES ALONG A QUASISTATIONARY FRONTAL BOUNDARY FROM SOUTHERN FRANCE OVER CENTRAL EUROPE TO WESTERN RUSSIA. TO THE SOUTH ... RELATIVELY MOIST AIRMASS AFFECTS SOUTHERN AND EASTERN CENTRAL EUROPE. ABOVE, SOUNDINGS INDICATE ELEVATED MIXED LAYER REACHING THE SURFACE OVER SOUTHEASTERN EUROPE.

DISCUSSION

...EASTERN EUROPE...
UNDERNEATH OF SOUTHWESTERLY CURRENT WEAK WAVES CROSS EASTERN EUROPE. AFFECTED AIRMASS SHOWS ADEQUATE MOISTURE IN THE RANGE OF QUASISTATIONARY FRONTAL BOUNDARY LAYER. TO THE SOUTH, ELEVATED MIXED LAYER REACHES THE SURFACE. GFS MODEL OUTPUT SUGGESTS CAPE AROUND 1000 J/KG IN THE RANGE OF FRONTAL BOUNDARY. AT THE SURFACE ... COLDFRONT MOVES INTO SOUTHEASTERN CENTRAL EUROPE. STORMS HAVE ALREADY FORMED IN THIS REGION AND PROPAGATE EASTWARD. TO THE SOUTH ... DEEP LAYER SHEAR IS MARGINAL AND THUNDERSTORMS SHOULD QUICKLY BECOME OUTFLOW DOMINANT. HOWEVER ... WELL MIXED BOUNDARY LAYER AND HIGH SPREAD SHOULD ALLOW FOR STRONG WINDGUSTS/ DOWNBURSTS. OVER THE NORTH OF AFFECTED REGION ... CAPE SHOULD BE SOMEWHAT LOWER. HOWEVER ... INCREASING JETSTREAK FROM SOUTHEASTERN GERMANY INTO POLAND /BOLAM SUGGESTS MORE THAN 50 KN OVER NORTHERN POLAND ON SUNDAY MORNING/ AND PROPAGATING SHORT WAVE OVER CENTRAL MEDITERRANEAN ASSOCIATED WITH INCREASING UPPER LEVEL WINDS SHOULD ASSIST FOR THUNDERSTORM ORGANIZATION. STRONG THUNDERSTORMS SHOULD FORM FROM THE BALKANS TO WESTERN UCRAINE, FORMING ONE OR TWO MCS DURING THE EVENING/ NIGHT HOURS. LARGE HAIL AND DAMAGING WINDS SHOULD BE THE MAIN SEVERE THREAT ... AND POSSIBLE A FEW ISOLATED TORNADOS, IF LOCAL ENHANCED SRH ALLOWS FOR SUPERCELLS AND LCL HIGHTS DECREASE IN THE EVENING.

#