DAY 2 CONVECTIVE OUTLOOK
VALID 06Z MON 31/03 - 06Z TUE 01/04 2003
ISSUED: 30/03 21:17Z
FORECASTER: GROENEMEIJER

GENERAL THUNDERSTORMS ARE FORECAST ACROSS MUCH OF SOUTHERN EUROPE, EASTERN POLAND, WESTERN BELARUS AND THE EXTREME NORTHWESTERN UKRAINE

GENERAL THUNDERSTORMS ARE FORECAST ACROSS THE NORTHWESTERN PARTS OF THE BRITISH ISLES

SYNOPSIS

THERE IS A WESTNORTHWESTERLY FLOW OVER THE NORTHERN HALF OF EUROPE. A STRONG JET STREAK IS PRESENT ON THE BASE OF A PRONOUNCED TROUGH OVER THE BALTIC SEA. IT IS FORECAST TO PROPAGATE SOUTHEASTWARD WHILE THE TROUGH AMPLIFIES OVER EASTERN EUROPE. BEHIND A RIDGE OVER THE NORTH SEA, THE EXIT REGION OF A NEW JET OVER THE ATLANTIC IS FORECAST TO REACH THE BRITISH ISLES MONDAY AFTERNOON. OVER THE WESTERN MEDITERRANEAN A WEAK UPPER LOW IS PRESENT THAT IS FORECAST TO GRADUALLY MOVE EASTWARD.

DISCUSSION

...SOUTHERN EUROPE...
AIR MASS OVER MUCH OF SOUTHERN EUROPE WILL DESTABILISE IN RESPONSE TO DAYTIME HEATING (UP TO 500 J/KG SBCAPE WILL FORM). THUNDERSTORMS WILL FORM IN THE AFTERNOON AND DECAY QUICKLY AFTER SUNSET. SOME SMALL HAIL MAY OCCUR WITH THE STORMS. NEAR UPPER LOW OVER MEDITERRANEAN SOME STORMS ARE LIKELY ONGOING AT THE BEGINNING OF THE PERIOD AND STORMS WILL LIKELY CONTINUE OVERNIGHT.

...POLAND, WESTERN BELARUS AND NORTHWESTERN UKRAINE...
BEHIND A COLD FRONT MOVING SOUTHEASTWARD OVER THE AREA SOME CONVECTION WILL LIKELY DEVELOP AHEAD OF THE UPPER TROUGH AXIS DURING THE MORNING. INSTABILITY IS FORECAST TO BE LOW. SOME STRONG WIND GUSTS MAY OCCUR WITH THE CONVECTION, THOUGH THESE WILL LIKELY NOT REACH SEVERE LIMITS GIVEN ONLY MODERATE LOW-LEVEL SHEAR. CONVECTION WILL LIKELY DECAY DURING THE LATE AFTERNOON AS SOLAR HEATING DEMINISHES AND DRIER AIR IS ADVECTED AHEAD OF THE TROUGH.

...NORTHWESTERN BRITISH ISLES...
COLD FRONT WILL REACH THE BRITISH ISLES DURING THE EVENING. THERE IS AN INDICATION THAT A LINEAR CONVECTIVE SYSTEM MAY FORM ON A TRAILING SHORTWAVE TROUGH. GIVEN STRONG 35-40 KT WINDS AT 850 HPA, THERE IS SOME CONCERN THAT THE ASSOCIATED GUSTS WILL REACH SEVERE LEVELS. PRIND IS THAT GUSTS WILL REACH 50 KNOTS ONLY IN EXPOSED PLACES, SO THAT A SLIGHT RISK IS NOT ISSUED AT THIS TIME. SOME SMALL HAIL MAY OCCUR WITH THE STORMS. AN UPGRADE TO SLIGHT RISK MAY BE NEEDED TOMORROW.

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