CONVECTIVE FORECAST
VALID 06Z THU 02/10 - 06Z FRI 03/10 2003
ISSUED: 01/10 18:04Z
FORECASTER: HUGO

General thunderstorms are forecast across PARTS OF WESTERN & CENTRAL EUROPE

SYNOPSIS

A closed upper level trough will dominate over Western Europe as a sharpening and developing upper level trough approaches the British Isles during the course of the discussion period...A short wave upper level trough in association with a slack region of surface low pressure will effected parts of Scandinavia, Germany & Poland during the forecast period...The rest of Europe will be dominated by a slack pressure high pressure gradient with a 500mb ridge dominated across central/southern regions of Europe...

DISCUSSION

...GEN TSTSM/SEE TXT REGION...
An unsettled spell of weather will be effecting parts of Western and Central Europe during the discussion period bring the risk of convective/thunderstorm activity...Convective aswell as frontal thunderstorm activity is possible within the GEN RISK/SEE TXT region during the course of the discussion period...Convection is likely to initiate during the course of the morning anywhere within the GEN RISK region...Forecast soundings over Spain and parts of Southern France show quite intense deep layer shear (0-6KM >45-50KT) coupled with some reasonable helicity values (0-3KM >150m2/s2) so any convective activity maywell become multicelluar (isolated risk of supercell activity) however soundings show quite poor levels of convective instability in relation to low dew point and ambient temperatures levels, so as a result convective activity is not expected to be widespread...One region of specific interest is over parts of the Central Med and into Italy...Forecast soundings for the region during the course of tomorrow show quite intense CAPE values with lowest 30hPa MLCAPE values generally exceeding 1,200j/kg to 1,500j/kg with higher SBCAPE values...However what is of main importance is very large CIN values in excess of -150 to -200j/kg for the region, so while the mid to upper level atmosphere maybe highly unstable the large CIN values are likely to restrict any convective activity within this region...However if convection is initiated then quite intense thunderstorm activity may occur in relation to a large release of low level moisture and heat as surface dew points are expected to exceed 20C along with ambient temperatures generally in excess of 25C to 30C...An update maybe needed during the course of the Thursday because there will be a fine line over the next 24 to 36hrs in relation to little or no convection or quite intense and maybe severe convection in relation to the high shear and helicity values over Iberia and France along with quite intense CAPE values over parts of the Central Med, as long as convection can initiate...

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