DAY 1 CONVECTIVE OUTLOOK
VALID 21Z FRI 17/01 - 12Z SAT 18/01 2003
ISSUED: 17/01 20:55Z
FORECASTER: DAHL

GENERAL THUNDERSTORMS ARE FORECAST ACROSS THE NORTHERN NORTH SEA.

SYNOPSIS

MEANDERING BAND OF INTENSE UPPER WESTERLIES STRETCHING ACROSS THE NORTHERN HALF OF EUROPE. SHORTWAVE TROUGH ATTM AFFECTING THE W NORTH SEA AND FRANCE... WILL LIFT NORTHEAST AND REACH THE BALTIC STATES TOWARDS THE END OF THE PERIOD. RATHER INTENSE SRN STREAM VORT MAX ATTM OVER N TUNESIA... WILL DECELERATE NORTH TO BECOME STATIONARY OVER THE S TYRRHENIAN SEA BY SATURDAY 12Z. AT LOW LEVELS... CYCLOGENESIS IS UNDERWAY OVER THE CNTRL MEDITERRANEAN SEA AHEAD OF THE SRN STREAM VORT MAX... WITH WEAK PLUME OF SUBTROPICAL-ATLANTIC MOISTURE PRESENT TO THE EAST AND NORTH OF THE LOW CENTER. FARTHER N... DEEP/EXTENSIVE LOW PRESSURE SYSTEM IS COVERING THE NORTH SEA AND MUCH OF THE NORTHEASTERN ATLANTIC. TRAILING/WEAKENING COLD FRONT ASSOCIATED WITH THE NRN STREAM TROUGH WILL SWEEP ACROSS SRN SCANDINAVIA AND THE W BALTIC STATES UNTIL SATURDAY 12Z.

DISCUSSION

...NORTH SEA...
BAND OF OF CELLULAR CONVECTION IS PRESENT OVER THE NRN NORTH SEA BENEATH ELONGATED CVA MAX. THOUGH LIGHTNING DATA SUGGEST NO TSTMS WITH THIS CONVECTION... ISOLATED CG STRIKES APPEAR QUITE LIKELY. ALSO... GIVEN ABOUT 100 KNOTS SHEAR MAGNITUDE IN THE CLOUD-BEARING LAYER... ISOLATED WIND GUSTS OF 60+ KNOTS SHOULD BE POSSIBLE ALONG WITH SMALL HAIL.

...CNTRL MEDITERRANEAN...
NARROW PLUME OF HIGH THETA-E AHEAD OF THE COLD FRONT ASSOCIATED WITH THE CNTRL MEDITERRANEAN LOW... IS NOT SAMPLED BY RADIOSONDE NETWORK. HOWEVER... LIGHTNING DATA INDICATE NO CG LIGHTNING STRIKES HAVE OCCURRED OVER THE PAST COUPLE OF HOURS. GIVEN THAT NO SIGNIFICANT INCREASE IN LARGE-SCALE UVM IS EXPECTED ATTM... DEVELOPMENT OF TSTMS APPEARS RATHER UNLIKELY TONIGHT.

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