Day 2 Convective Outlook
 


VALID 06Z FRI 15/11 - 06Z SAT 16/11 2002
ISSUED: 14/11 20:04Z
FORECASTER: GROENEMEIJER

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN ITALY, SOUTHEASTERN FRANCE AND THE WESTERN MEDITERRENEAN

GENERAL THUNDERSTORMS ARE FORECAST ACROSS PARTS OF THE BRITISH ISLES, FRANCE, THE IBERIC PENINSULA, THE WESTERN MEDITERRANEAN INCLUDING THE ADRIATIC.

SYNOPSIS

A DEEP TROUGH IS LOCATED OVER WESTERN EUROPE WITH ITS BASE OVER THE IBERIAN PENINSULA. BAROCLINIC WAVES ARE TRAVELLING ALONG JET ON SOUTHEASTERN FLANK OF THIS SYSTEM. THE AIR MASS OVER THE WESTERN MEDITERRANEAN IS MARGINALLY UNSTABLE.

DISCUSSION

...WESTERN MEDITERRANEAN, SOUTHEASTERN FRANCE, NORTHERN ITALY EXCEPT SOUTHERN SLOPES OF THE ALPS...
NEW BAROCLINIC WAVE DEVELOPING UNDER UPPER JET IS EXPECTED TO BE LOCATED NEAR/JUST SOUTHEAST OF SPAIN AT THE BEGINNING OF THE PERIOD. MID-LEVEL WINDS ARE EXPECTED TO INCREASE SIGNIFICANTLY ON THE APPROACH OF THIS SYSTEM TO AROUND 70 KNOTS. A VERY STRONG SHEAR PROFILE WILL RESULT IN VERY HIGH 0-3KM S.R.HELICITY VALUES OF AS HIGH AS 400 - 800 M2/S2 EXPECTED IN PLACES. LIMITING FACTOR TO THIS SEVERE EVENT IS INSTABILITY. CAPE WILL GENERALLY BE LESS THAN 1000 J/KG. AS MID-LEVELS ARE EXPECTED TO BE QUITE DRY ABOVE SHALLOW MOIST LAYER, STRONG OUTFLOWS ARE POSSIBLE. MCS WILL LIKELY FORM NEAR SOUTHEASTERN SPAIN IN THE MORNING AFFECTING THE BALEARES IN THE AFTERNOON. ALONG THE COLD-FRONT A LINEAR MCS IS EXPECTED TO FORM. THE ACTIVITY IS EXPECTED TO TRACK EASTNORTHEASTWARD AND AFFECTING SOUTHEASTERN FRANCE AND NORTHERN AND WESTERN ITALY IN THE EVENING HOURS. THERE IS A CHANCE FOR TORNADOES, AND VERY STRONG /UP TO 80 KT/ DOWNBURSTS AS WELL AS SOME MARGINALLY SEVERE HAIL. AN UPGRADE TO MODERATE RISK MAY BE NECESSARY.

...SOUTHERN SLOPES OF THE ALPS...
STRONG WARM ADVECTION REGIME AN MOISTURE ADVECTION AHEAD OF COLD FRONT IN COMBINATION WITH STRONG UPSLOPE WINDS AND MARGINAL INSTABILITY WILL CAUSE INTENSE DEEP MOIST CONVECTION TO BE PRESENT DURING THE WHOLE OF THE FORECAST PERIOD. THIS WILL LIKELY CAUSE FLOODING IN SOME PLACES.

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