DAY 2 CONVECTIVE OUTLOOK
VALID 06Z SAT 15/03 - 06Z SUN 16/03 2003
ISSUED: 14/03 17:00Z
FORECASTER: DAHL

GENERAL THUNDERSTORMS ARE FORECAST ACROSS THE IBERIAN PENINSULA AND THE SOUTHERN MEDITERRANEAN SEA.

SYNOPSIS

OMEGA BLOCK IS ESTABLISHING ACROSS EUROPE... WITH LOW GEOPOTENTIAL HEIGHTS PRESENT OVER THE EASTERN AND SOUTHEASTERN PARTS OF EUROPE. FEATURE OF PRIMARY INTEREST THIS PERIOD WILL BE RAPIDLY SOUTHWARD MIGRATING UPPER TROUGH OVER SE EUROPE WHICH IS EXPECTED TO BE CENTERED OVER THE CENTRAL MEDITERRANEAN SEA TOWARDS THE END OF THE PERIOD. RATHER WEAK QUASI-STATIONARY UPPER TROUGH WILL CONTINUE TO AFFECT THE IBERIAN PENINSULA. AT THE SURFACE... LARGE HIGH PRESSURE SYSTEM COVERING MAJOR PARTS OF EUROPE... ADVECTING POLAR AIRMASSES INTO MOST OF THE FORECAST AREA. MAIN BAROCLINIC ZONE STRETCHING FROM S OF GREECE ACROSS THE MEDITERRANEAN SEA INTO S FRANCE.

DISCUSSION

...SOUTH MEDITERRANEAN...
WITH THE SOUTHWARD PROPAGATION OF THE MAIN VORT MAX ASSOCIATED WITH THE SE EUROPEAN UPPER TROUGH... BAND OF MODERATELY STRONG DCVA IS EXPECTED TO DEVELOP EARLY IN THE FORECAST PERDIOD CURVING FROM SE FRANCE ACROSS CENTRAL ITALY INTO THE SOUTH BALKAN STATES. HOWEVER... THIS BAND APPEARS TO REMAIN WELL NORTH OF THE COLD FRONT AND THE WARM AIRMASS. WIND FIELDS DO NOT SUGGEST MUCH ELEVATED MOISTURE/THETA-E TO BE PRESENT NORTH OF THE FRONTAL BOUNDARY AND DEEP CONVECTION IS UNLIKELY TO EVOLVE IN ASSOCIATION WITH THIS ELONGATED CVA MAXIMUM. LOBE OF INTENSE WARM ADVECTION ASSOCIATED WITH A FRONTAL WAVE WHICH IS EXPECTED TO DEVELOP BY SATURDAY 12Z S OF ITALY... WILL AUGMENT LARGE-SCALE ASCENT OVER THIS REGION. UNCERTAINTIES EXIST AS TO THE DEGREE OF INSTABILITY OF THE AIRMASS S OF THE FRONT... AVAILABLE SOUNDINGS OF THE WARM AIR INDICATE QUITE MEAGER LOW-LEVEL MOISTURE AND STABLE LAPSE RATES... AND CONFIDENCE THAT SIGNIFICANT INSTABILITY WILL DEVELOP WITH THE ADVENT OF THE UPPER TROUGH IS RATHER LOW. HOWEVER... SHEETS OF WEAK ELEVATED INSTABILITY COULD DEVELOP IN THE WAA REGIME N OF THE SURFACE FRONT. THOUGH SOME LIGHTNING WILL POSSIBLE THEN... THREAT OF SEVERE THUNDERSTORMS APPEARS MINIMAL GIVEN ANTICIPATED POOR INSTABILITY.

...IBERIAN PENINSULA...
BOUNDARY LAYER IN THE WARM SECTOR OVER SPAIN APPEARS TO MOISTEN WITH SUSTAINED WARM/MOIST ADVECTION... AND ELEVATED THUNDERSTORMS SHOULD RE-DEVELOP LATE IN THE DAY/EVENING AND OVERNIGHT PRIMARILY ALONG THE WARM FRONT OVER EAST SPAIN... DIURNALLY-ENHANCED THUNDERSTORMS MAY ALSO DEVELOP ALONG THE COLD FRONT FARTHER WEST. SEVERE THREAT APPEARS TO BE MINIMAL GIVEN WEAK SHEAR AND THERMODYNAMIC PROFILES. HOWEVER... RATHER DEEPLY MIXED SUBCLOUD LAYER AHEAD OF THE COLD FRONT... MAY ENHANCE THE CHANCE OF A FEW STRONG WIND GUSTS WHICH SHOULD REMAIN WELL BELOW SEVERE LEVELS THOUGH.

#