DAY 2 CONVECTIVE OUTLOOK
VALID 06Z FRI 28/03 - 06Z SAT 29/03 2003
ISSUED: 27/03 17:52Z
FORECASTER: GATZEN

GENERAL THUNDERSTORMS ARE FORECAST ACROSS SOUTHWESTERN EUROPE

GENERAL THUNDERSTORMS ARE FORECAST ACROSS EASTERN CENTRAL EUROPE

SYNOPSIS

EUROPEAN RIDGE WEAKENS, AND LONG-WAVE TROUGH OVER WESTERN EUROPE PROPAGATES EASTWARD. NORTHERN BRANCH OF POLAR JETSTREAM IS PRESENT OVER SCANDINAVIA AND MOVES SOUTHWARD WHILE THE SOUTHERN BRANCH EFFECTS NORTHERN AFRICA, WHERE WINDSPEED REACHES 100 KNOTS AT 300 HPA. WITHIN BOTH FLOW PATTERNS, STRONG VORT-MAXIMA MIGRATE EASTWARD. OVER CENTRAL EUROPE, FLOW IS QUITE WEAK. CUT-OFF LOW OVER GERMANY WILL MOVE EASTWARD SUPPORTING THUNDERSTORM DEVELOPMENT.

DISCUSSION

...SOUTHWESTERN EUROPE...
OCCLUSION OF SURFACE LOW NORTHWEST OF THE IBERIAN PENINSULA IS FORECAST TO REACH THE WESTERN MEDITERRANEAN TONIGHT. WEST OF THE FRONT ... MOIST AIRMASS ORIGINATED FROM THE SUBTROPICAL ATLANTIC ENTERS PORTUGAL AND SPAIN. THIS AIRMASS IS CONVECTIVELY MIXED AND WILL LIKELY DESTABILIZE DURING THE DAY. THUNDERSTORM ACTIVITY MAY FOCUS OVER EASTERN SPAIN AND SPREAD EASTWARD INTO WESTERN MEDITERRANEAN. FRIDAY AFTERNOON ... STRONG SHORT-WAVE TROUGH IS PROGGED OVER SOUTHERN PORTUGAL. FRONTAL RAINBAND IS EXPECTED NORTHEAST OF THE SURFACE LOW. WEST OF THE ASSOCIATED COLDFRONT ... CONVECTIVELY MIXED AIRMASS SHOULD LEAD TO NEW THUNDERSTORM ACTICITY. STRONG VERTICAL SHEAR WITHIN THE LOWEST 6 KM IS FORECAST OVER SOUTHERN IBERIAN PENINSULA, AND ORGANISED THUNDERSTORMS COULD FORM IN THE EVENING. STRONG WIND GUSTS UNDER 50 KNOTS ARE EXPECTED WHICH DOES NOT WARRANT A SLIGHT RISK.

...EASTERN CENTRAL EUROPE...
CUT-OFF LOW WILL MOVE SLOWLY EASTWARD. DUE TO DAYTIME HEATING, THUNDERSTROMS SHOULD FORM OVER POLAND AND CZECH REPUBLIC. CAPE WILL LIKELY REACH MORE THAN 200 J/KG, AND PROBABLY SOME THUNDERSTORMS WILL PRODUCE SMALL HAIL.

#