Valid: Sat 09 Jul 2011 06:00 to Sun 10 Jul 2011 06:00 UTC
Issued: Sat 09 Jul 2011 08:35
A level 1 was issued for west-central France, Switzerland, extreme norhtwestern Italy, northwestern Austria and extreme southern Germany, mainly for large hail.
A southwesterly flow is present over much of western and central Europe upstream of a ridge extending from Karelia across the Baltic States towards the central Balkans. A diffuse zone of temperature gradient extends from the Baltic Sea across Germany and France into northwest Spain.
Alps and vicinity...
A shortwave trough over the Bay of Biscay is expected to move northeastward during the day. Ascent ahead of the system should overspread the Alps during the afternoon and will aid the development of convective storms. MLCAPE values of around 1000 J/kg are expected to develop north of the mountains, and up to 2000 J/kg in the Po Valley. The combination with moderate, about 15-20 m/s 0-6 km bulk shear, suggests that storms may locally obtain rotating updrafts in addition to a few well-organized multicells. Therefore, a couple of large hail events appear possible.