Storm Forecast
Valid: Thu 08 Feb 2007 08:00 to Fri 09 Feb 2007 06:00 UTC
Issued: Thu 08 Feb 2007 07:58
Forecaster: GATZEN

SYNOPSIS

Upper polar jet today present from Bay of Biscay to southern/eastern Germany and Belarus/Ukraine. An embedded jet streak travels eastward over France and Alpine region during the period. In the wake of this jet streak, a short-wave trough evades into south-western Europe, while another, sharp trough now over central Mediterranean moves eastward. At lower levels, a frontal boundary is present underneath the polar jet. Rather warm air mass spreads into south-western Europe in the range of approaching trough, while most of the Mediterranean is affected by cool, but unstable air mass.

Northern France

South of the frontal boundary, a tongue of moist and warm maritime air mass is forecast to spread into northern France. In the range of the upper vort-max/jet streak, models indicate instability, and showers/thunderstorms have already formed W of northern France. Today, expect that convective activity will spread into northern France, vertical wind shear south of the frontal boundary will become relatively favorable for organized thunderstorms, given LLS of 10 m/s and DLS of 20-30 m/s. Latest GFS indicates low-level helicity of 100 J/kg. Limiting factors will be rather weak instability as well as quite weak forcing in the wake of the trough that is forecast over western Germany in the evening hours. Chance for a few mesocyclones or bowing lines is foecast to be rather low, and only isolated hail/wind events or a brief tornado are not ruled out today.