DAY 1 CONVECTIVE OUTLOOK
VALID 13Z SAT 01/02 - 06Z SUN 02/02 2003
ISSUED: 01/02 14:14Z
FORECASTER: GROENEMEIJER

THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS CRETE AND EXTREME SOUTHWESTERN TURKEY

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF SOUTHERN AND EASTERN CRETE AND SOUTHWESTERN TURKEY

GENERAL THUNDERSTORMS ARE FORECAST ACROSS THE CENTRAL AND EASTERN MEDITERRANEAN REGION AS WELL AS THE NORTHERN BRITISH ISLES, NORWAY AND ADJACENT PARTS OF THE ATLANTIC OCEAN

SYNOPSIS

A STRONG MID/UPPER JET STREAK IS PROPAGATING EASTWARD ON THE SOUTHERN FLANK OF A UPPER AND SURFACE LOW OVER THE MEDITERRANEAN. A WEAK SW-NE RIDGE IS PRESENT FORM SOUTHERN FRANCE TO THE BALTIC SEA. A NEW STRONG JET OVER THE ATLANTIC, WITH ITS EXIT REGION OVER THE BRITISH ISLES IS PROPAGATING EASTWARD.

DISCUSSION

...GREECE, TURKEY...
SURFACE LOW IS LOCATED JUST SOUTH OF ITALY AT THE BEGINNING OF THE PERIOD. THE ASSOCIATED COLD FRONT IS PRESENT SOME 300 KM WEST OF GREECE/CRETE AND IS EXPECTED TO MOVE QUITE RAPIDLY EASTWARD, REACHING THE TURKISH WEST COAST JUST AFTER MIDNIGHT. SOME DISTANCE SOUTH OF THE CYCLONE CENTER 50-60 SOUTHWESTERLY WINDS AT 500 HPA OVERSPREAD 30-40 KNOT SOUTHEASTERLY WINDS AT 925 HPA CREATING STRONGLY VEERING WIND PROFILES AND HIGHLY HELICAL INFLOW TO STORMS ON COLD FRONT. WARM ADVECTION AHEAD OF COLD FRONT CREATES SLIGHT INSTABILITY WITH SBCAPE VALUES LOCALLY EXCEEDING 500 J/KG. THERE IS A HIGH PROBABILITY OF SUPERCELLS FORMING AT OR JUST AHEAD OF COLD FRONT. THESE STORMS AS WELL AS LINEARLY ORGANIZED CONVECTION ON THE COLD WILL LIKELY PRODUCE SEVERE WIND GUSTS IN PLACES. THE SUPERCELLS HAVE THE POTENTIAL TO PRODUCE LARGE HAIL AND A FEW TORNADOES AS WELL. THE HIGHEST CHANCE OF TORNADOES WILL BE NEAR CRETE AND THE SOUTHWESTERN TURKISH COASTAL AREAS AS INSTABILITY WILL BE HIGHEST THERE AND EXPECTED LCL LEVELS THE LOWEST. BEHIND THE COLD FRONT INSTABILITY WILL BE SUFFICIENT FOR ADDITIONAL THUNDERSTORM DEVELOPMENT NEAR THE CYCLONE CENTER. GIVEN WEAKER WIND PROFILES, THESE STORMS ARE NOT EXPECTED TO POSE A SIGNIFICANT THREAT OF SEVERE WEATHER.

...NORTHWESTERN BRITISH ISLES...
AS INSTABILITY IS INCREASING IN POLAR AIR MASS BEHIND A COLD FRONT, CONVECTION WILL GAIN INTENSITY. MORE AND MORE SHOWERS WILL BE ACCOMPANIED BY THUNDER AND THE POTENTIAL OF SOME STRONG...POSSIBLY MARGINALLY SEVERE... WIND GUSTS WILL ALSO INCREASE GRADUALLY...ALSO BECAUSE BACKGROUND WIND FIELD WILL BECOME STRONGER. HOWEVER...OVERALL THREAT SEEMS TOO LOW TO REQUIRE A CATEGORICAL RISK.

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