CONVECTIVE FORECAST
VALID 06Z WED 08/09 - 06Z THU 09/09 2004
ISSUED: 07/09 23:55Z
FORECASTER: GROENEMEIJER

General thunderstorms are forecast across Spain, northern Portugal, southern France and across much of eastern Europe including the northeastern Balkans.

SYNOPSIS

Wednesday at 06Z... at mid and upper levels, a high pressure area is situated over eastern Britain and a low-pressure area just west of northwestern Spain. The high pressure area transforms into a meridionally oriented ridge over western continental Europe and the low transforms into a trough. Downstream... a NE-SW oriented trough with its axis over central Finland amplifies while moving southward and reaches Belarus and the northern Ukraine on Thursday morning.

DISCUSSION

...Spain...
low and mid-level lapse rates have become less steep over the last 24 hours, negatively impacting latent instability. Wind shear has also gradually become smaller. Low-level moisture however, is expected to increase from the east. Present thinking is that scattered storms will form during the afternoon and early evening hours. Shear should be adequate to allow for multicell devlopment, so that a small chance of large hail and rather strong winds gusts will be possible with any storm that forms. Overall threat, however, seems too low to warrant a risk category.

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