Forecast Update
Valid: Sat 23 May 2009 15:00 to Sun 24 May 2009 06:00 UTC
Issued: Sat 23 May 2009 15:43
Forecaster: GROENEMEIJER

A level 1 was issued for parts of France and Spain mainly for large hail and damaging winds.

A level 1 was issued for the E Alpine region and N Slovenia mainly for large hail.

A level 1 was issued for southern parts of the central Russian Upland for severe winds and tornadoes.

SYNOPSIS

Refer to the original convective forecast...

DISCUSSION

France...

At 15 UTC a warm front stretches from near La Rochelle to near Bern. South of the front, dew points have risen to 18-20C. In vicinity of an old outflow boundary from the Bougogne to the northern Auvergne, storms are initiating. given that about 1500-2000 J/kg and 15 m/s 0-3km bulk shear are ptresent in that area, storms can aquire rotating and will have the chance of producing large, possibly very large hail and possibly some damaging winds. Current thinking is that storms coverage will however remain low, not warranting a higher risk level than 1. Elsewhere across southern France, a few storms may also develop, most likely in the southwest. Additionally, During the night, elevated storm systems could develop along the northward moving warm front, that should, however, be mostly non-severe.

Spain...

Storms have initiated across several regions, including the eastern third of the country across which a rather strong southerly jet is present, which creates quite a bit of vertical wind shear (25 m/s in the 0-6km layer). Even though CAPE appears to be quite limited, a couple of storms may produce severe weather in during the remainder of the day. the most likely severe weather modes are severe winds and marginally severe hail. The storms will likely weaken gradually after sunset.