DAY 1 CONVECTIVE OUTLOOK
VALID 06Z SUN 16/03 - 06Z MON 17/03 2003
ISSUED: 16/03 09:29Z
FORECASTER: VAN DER VELDE

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS CRETE AND SURROUNDING MEDITERRENEAN

GENERAL THUNDERSTORMS ARE FORECAST ACROSS ADRIATIC,S&E ITALY, N TUNESIA

SYNOPSIS

LARGE OMEGA BLOCK HIGH PRESSURE AREA WITH ITS >1040 HPA CORE OVER THE NORTH SEA/NETHERLANDS/GERMANY/DENMARK AREA SLOWLY RETREATS WESTWARD TOWARDS TH UK AND KEEPS FRONTAL DISTURBANCES FAR AWAY FROM THE EUROPEAN CONTINENT. STABLE AIR IS IN PLACE OVER EUROPE, EXCEPT FOR THE MEDITERRENEAN AREA, WHERE COLD AIR OFF THE CONTINENT MEETS THE WARMER SEA WHILE AN UPPER LEVEL LOW FILLED WITH COLD AIR DESCENDS INTO THE EASTERN PART OF THE MEDITERRENEAN. THIS WILL CAUSE INSTABILITIES UP TO 200 J/KG TO BE IN PLACE OVER MUCH OF THE EASTERN PART OF THE MED., AND CAUSES A SFC THROUGH AT THE BEGINNING OF THE FCST PERIOD ALIGNED WITH THE ADRIATIC TO DEEPEN AND GENERATE MORE CYCLONIC FLOW IN WHICH DISTURBANCES CAUSE STORMS. TOWARDS THE END OF THE FCST PERIOD (MON 00Z), WARMER AIR OVER LIBYA COLLIDES WITH COLD AIR FROM THE NORTH AHEAD OF THE UPPER LEVEL LOW CAUSING CYCLOGENESIS ACROSS THE SURFACE TEMPERATURE BOUNDARY OVER THE SOUTHERN MEDITERRANEAN. THE DEEPENING SFC LOW WILL MOVE TOWARDS TURKEY BY THE END OF THE PERIOD.

DISCUSSION

...CRETE AND SURROUNDING MEDITERRENEAN...
AROUND MON 00Z, INSTABILITIES OVER 250 J/KG ASSOCIATED WITH WARM AIR AT THE SOUTHEASTERN FLANK OF THE LOW ARE SOMEWHAT CAPPED EAST OF THE ASSOCIATED COLD FRONT... HOWEVER, STRONG UVMS AND SFC CONVERGENCE INDICATED BY THE GFS MODEL WOULD LIKELY OVERCOME THE CAP, WHILE BACKED SFC WINDS GENERATE HIGH HELICITY VALUES OVER 250 M2/S2 AND 0-6 KM SHEAR OVER 40 KTS IN THE WARM SECTOR... THUS, SUPERCELLS ARE POSSIBLE IF STORMS DEVELOP. THE MAIN RISK WILL BE MARGINALLY SEVERE LARGE HAIL... AND STRONG GUSTS OVER 40 KTS IF A MCS DEVELOPS UNDER THESE SHEAR/LARGE SCALE TRIGGER CONDITIONS. TORNADO THREAT IS MARGINAL DUE TO 0-1 KM SHEAR GENERALLY LESS THAN 15 KTS... ALTHOUGH LCLS ARE QUITE LOW (400-600M).

...ADRIATIC,S&E ITALY, N TUNESIA...
INSTABILITIES GENERALLY 100-200 J/KG AND SFC DISTURBANCES (ALSO OROGRAPHICALLY INDUCED) IN THE CYCLONIC AIRFLOW WILL EASILY TRIGGER TSMS. THE SEVERE THREAT SHOULD BE LOW, GIVEN THE LOW AMOUNT OF VERTICAL SHEAR. CLUSTERING OF STORMS MAY OCCUR GIVEN THE WEAK CAPPING. GUSTS OCCURRING WITH THESE STORMS SHOULD GENERALLY BE LESS THAN 40-45 KNOTS. SPORADIC THUNDER MAY OCCUR ELSEWHERE OUTSIDE THE GEN TSTMS AREAS.

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