VALID 12Z FRI 11/10 - 06Z SAT 12/10 2002
ISSUED: FRI 11/10 11:35Z
FORECASTER: DAHL

THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS ACROSS THE IONIAN SEA AND THE BALKAN STATES.

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS S ITALY.

GENERAL THUNDERSTORMS ARE FORECAST ACROSS THE WESTERN MEDITERRANEAN SEA. THE WESTERN MEDITERRANEAN SEA. THE WESTERN MEDITERRANEAN SEA. THE WESTERN MEDITERRANEAN SEA. THE WESTERN MEDITERRANEAN SEA.

SYNOPSIS

PRIMARY FEATURE THIS PERIOD WILL BE INTENSE UPPER LOW COVERING THE WESTERN AND CNTRL MEDITERRANEAN REGIONS...THIS FEATURE WILL SLOWLY CONTINUE EASTWARDS...WITH SEVERAL VORT MAXIMA ROTATING AROUND ITS PERIPHERY. NORTHERN BRANCH OF FRONTAL ZONE IS AFFECTED BY OMEGA-TYPE BLOCK OVER THE NORTHERN ATLANTIC AND NORTHERN EUROPEAN STATES. SHORT-WAVE TROUGH IS DIGGING AT THE S RIM OF THE ASSOCIATED LARGE-SCALE TROUGH OVER THE N ATLANTIC...WHICH HAS INDUCED EXTENSIVE SFC LOW COVERING MUCH OF THE N-CNTRL ATLANTIC. AT LOW LEVELS... NARROW/ELONGATED PLUME OF MOIST/UNSTABLE LOW-LEVEL AIRMASS IS ADVECTING NORTHWARDS AHEAD OF THE MEDITERRANEAN UPPER LOW...AND WILL AFFECT ALL OF THE BALKAN STATES AND THE IONIAN SEA DURING THIS PERIOD.

DISCUSSION

...IONIAN SEA...BALKAN STATES...
MIXED PARCELS WITHING THE WARM/MOIST PLUME AHEAD OF THE COLD FRONT...ATTM STRETCHING ACROSS THE IONIAN SEA INTO THE BALKAN STATES...HAVE CAPES ON THE ORDER OF 2000 J/KG...WITH TEMPERATURES AND DEWPOINTS IN THE LOW 70S /AROUND 20 TO 24C/... RESULTING IN QUITE LOW LCL HEIGHTS. DEEP LAYER SHEAR WILL BE MORE THAN SUFFICIENT FOR SEVERE EVOLUTION... MID-LEVEL JET OF UP TO 70 KNOTS IS EXPECTED TO OVERSPREAD THIS AIRMASS. ATTM FIRST TSTMS APPEAR TO BE INITIATING ALONG/AHEAD OF THE COLD FRONT OVER THE IONIAN SEA...AND SHOULD SPREAD INTO THE BALKAN STATES. SINCE STRONG THETA-E ADVECTION IS IN PLACE AHEAD OF THE FRONT...DECENTLY VEERING LOW-LEVEL WINDS SHOULD BE IN PLACE...WHICH MAY LOCALLY BE AUGMENTED BY OROGRAPHY AND BY OUTFLOW BOUNDARIES...AND SUPERCELLS APPEAR TO BE LIKELY...GIVEN LOW LCL HEIGHTS AND THE ASSOCIATED TENDENCY TO GENERATE PERSISTANT LOW-LEVEL ROTATION...TORNADOES MAY WELL OCCUR TODAY/TONIGHT...ALONG WITH LARGE HAIL AND DAMAGING WIND GUSTS. TSTMS MAY CONSOLIDATE INTO ONE OR MORE LARGER...PRIMARILY LINEAR MCS'S LATER TONIGHT WITH PRIMARY THREATS SHIFTING TOWARDS DAMAGING WIND GUSTS AND LARGE HAIL ALONG WITH LOCAL FLASH FLOODING.

...WESTERN MEDITERRANEAN SEA...S ITALY...
CONVECTION HAS DEVELOPED OVER THE WESTERN MEDITERRANEAN SEA... WHICH APPEARS TO BE ASSOCIATED WITH LOW-LEVEL WAA AS WARM/MOIST AIRMASS IS WRAPPING AROUND THE LOW CENTER. SHEAR ACROSS THAT REGION SHOULD INTERMITTANTLY WEAKEN OVER THE NEXT FEW HOURS AS THE CENTER OF THE UPPER LOW APPROACHES...AND SHOULD REJUVENILE DURING THE NIGHT AS NEXT VORT MAX RUNS IN. SOUNDINGS INDICATE QUITE MEAGER THERMODYNAMIC PROFILES... WITH MOIST/NEUTRAL LAPSE RATES. PRIND THAT MAJORITY OF THE STORMS WILL STRUGGLE TO BECOME SEVERE DURING THE NEXT FEW HOURS. HOWEVER...AS SHEAR INCREASES LATE TODAY/TONIGHT WITH THE ADVENT OF THE VORT MAX...A FEW SEVERE TSTMS SHOULD BE POSSIBLE DESPITE WEAK THERMODYNAMIC SUPPORT ACROSS THE TYRRHENIAN SEA...PRIMARY THREATS SHOULD BE MARGINALLY SEVERE CONVECTIVE OUTFLOW WINDS AS WELL AS MARGINALLY SEVERE HAIL. TSTMS MAY SPREAD AS FAR SE AS TO SICITY BY EARLY MORNING.

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