VALID 06Z THU 07/11 - 00Z FRI 08/11 2002
ISSUED: 06/11 22:57Z
FORECASTER: DAHL

GENERAL THUNDERSTORMS ARE FORECAST ACROSS W MEDITERRANEAN

GENERAL THUNDERSTORMS ARE FORECAST ACROSS SE GREECE...AEGEAN SEA

GENERAL THUNDERSTORMS ARE FORECAST ACROSS W FRANCE...BENELUX...W GERMANY

SYNOPSIS

MAIN FEATURE WILL BE INTENSE VORT MAX WHICH IS EXPECTED TO REACH THE NW MEDITERRANEAN EARLY THURSDAY MORNING. ALTHOUGH MODELS COHERENTLY SIMULATE CYCLOGENESIS OVER THE W-CNTRL MEDITERRANEAN SEA... SOLUTIONS DIFFER SIGNIFICANTLY AS TO STRENGTH OF THE DEVELOPING LOW. UKMO APPEARS OFFERS STRONGEST/MOST RAPID DEVELOPMENT AND APPEARS TO BE SOMEWHAT OVERDONE COMPARING IT WITH LATER /12Z/ SOLUTIONS OF GME AND AVN. NONETHELESS... SUBSTANTIAL UNCERTAINTY EXISTS WITH RESPECT TO THIS FEATURE.

FOR CURRENT MAP CLECK HERE.

DISCUSSION

...W MEDITERRANEAN...
WARM AIRMASS INVOLVED WITH THE DEVELOPING SFC LOW...APPEARS TO HAVE RATHER POOR THERMODYNAMIC PROPERTIES...SUGGESTING THAT INSTABILITY MAY TURN OUT TO BE A PROBLEM...CURRENT THINKING IS THAT CONVECTION WILL HAVE BEST CHANCES TO DEVELOP IN THE POSTFRONTAL ENVIRONMENT W OF THE SFC LOW CENTER. WIND FIELD WILL BE STRONGEST AT THE W PERIPHERY OF THE VORT MAX...WHICH SHOULD BE WHERE POSTFRONTAL CONVECTION IS MOST LIKELY. HOWEVER...DEGREE OF DCVA-RELATED LIFT WILL BE LIMITED PER AVN MODEL FIELDS...AND LOW-LEVEL CAA MAY PROVE TO BE SUFFICIENTLY STRONG TO INHIBIT DEEP CONVECTIVE MIXING. LATER OBS HAVE TO BE AWAITED TO SPECIFY SEVERE THREAT.

...SE GREECE...AEGEAN SEA...
TSTMS SHOULD RE-DEVELOP DURING THE DAY ALONG THE COLD FRONT OVER SE GREECE AND THE AEGEAN SEA. DEGREE OF LARGE-SCALE SHEAR AS WELL AS INSTABILITY DO NOT SUGGEST MUCH OF A SEVERE THREAT...AND ALTHOUGH AN ISOLATED ROTATING UPDRAFT WITH AN ATTENDANT THREAT OF MARGINALLY SEVERE HAIL AND MAYBE A BRIEF TORNADO MAY DEVELOP IF SUSPECTED RIBBONS OF HIGH HELICITY ARE PICKED UP...A SLIGHT RISK IS NOT NECESSARY.

...W FRANCE...BENELUX...W GERMANY...
SHOWERS AND A FEW TSTMS SHOULD FORM OVER W FRANCE...BENELUX AND W GERMANY IN DEEP POLAR AIRMASS IN THE WAKE OF THE COLD FRONT. BAND OF STRONG UPPER WINDS SHOULD NOT AFFECT REGION OF DEEP CONVECTION...AND SEVERE TSTMS SHOULD BE UNLIKELY.

#