Storm Forecast
Valid: Tue 28 Aug 2012 06:00 to Wed 29 Aug 2012 06:00 UTC
Issued: Mon 27 Aug 2012 21:58
Forecaster: KOROSEC

A level 1 was issued for NE Iberia into southern France mainly for large hail and severe winds.

A level 1 was issued for western UK mainly for strong to severe wind gusts.

SYNOPSIS

Ridge builds up from Mediterranean towards central Europe while a trough over western Europe affects parts of SW Europe and UK. A baroclinic zone stretches from central Iberia NE-wards into France. Another trough over eastern Europe gradualy weakening while moving east into western Russia.

DISCUSSION

... NE Iberia into southern France ...

Convective activity is expected today across parts of SW Europe where hot/moist airmass continues advecting northwards along the western flank of the Mediterranean upper ridge. Very moist airmass with mixing ratios between 12 and 15 g/kg will spread into NE Spain and southern France, providing ample moisture for strong instability resulting during the daytime hours. Expect 1000-2000 J/kg MLCAPE locally. Jet streak rounding the trough should provide around 15-20 m/s of deep layer shear, which favours formation of organized isolated storms. Those should be both multicells and supercells, capable of producing large to very hail and damaging winds.

... western UK ...

Beneath the western European trough, a rather deep surface low slowly moves towards western UK with a frontal system. At least marginal instability will be in place once the quite cold mid levels overspread the region. Some storms might form and enhance threat for some strong winds across Ireland given the quite strong wind field around the cyclone. A marginal level 1 has been issued to cover this potential threat.