CONVECTIVE FORECAST
VALID 06Z SAT 12/04 - 06Z SUN 13/04 2003
ISSUED: 11/04 23:17Z
FORECASTER: GROENEMEIJER

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS NORTHERN ADRIATIC

GENERAL THUNDERSTORMS ARE FORECAST ACROSS FRANCE, MUCH OF THE CENTRAL MEDITERRANEAN, THE ALPS, THE NORTHERN BALKANS AND THE EXTREME WESTERN IBERIAN PENINSULA.

SYNOPSIS

A LONGWAVE RIDGE IS BUILDING QUICKLY OVER WESTERN EUROPE DOWNSTREAM OF AN AMPLYFYING UPPER TROUGH. A VORT MAX OVER SOUTHEASTERN FRANCE IS EXPECTED TO CUT-OFF AND MOVE ESATSOUTHEASTWARD TO THE WESTERN BALKANS. THUNDERSTORMS WILL FORM NEAR AND AHEAD OF THE VORT MAX. STRONG SOUTHERLY WINDS OVER FRANCE WILL ADVECT SLIGHTLY UNSTABLE AIR-MASS NORTHWARD. ESPECIALLY NEAR THE LEADING WARM FRONT SOME THUNDERSTORMS MAY DEVELOP. AT THE END OF THE PERIOD A COLD FRONT WILL BE APPROACHING IBERIA FROM THE WEST. ASSOCIATED STORMS MAY AFFECT THE COASTAL AREA JUST BEFORE THE END OF THE FORECAST PERIOD.

DISCUSSION

...NORTHERN ADRIATIC...
RISING MOTIONS AHEAD OF UPPER VORT MAX/COLD LOW WILL LIKELY TRIGGER THUNDERSTORM ACTIVITY OVER THE NORTHERN ADRIATIC DURING THE MORNING. GIVEN VEERING LOW-LEVEL WIND PROFILES, THERE IS A CHANCE THAT SHORT-LIVED ROTATION UPDRAFTS WILL FORM. THIS YIELDS A SMALL CHANCE OF LARGE HAIL AND SEVERE GUSTS. A SHORT-LIVED WEAK TORNADO OR TWO CAN ALSO NOT BE RULED OUT GIVEN MODERATE TO LOW LCL HEIGHTS AND TOPOGRAPHY THAT WILL LIKELY INDUCE BACKED SURFACE WINDS.

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