Storm Forecast
Valid: Sun 30 Mar 2008 06:00 to Mon 31 Mar 2008 06:00 UTC
Issued: Sat 29 Mar 2008 22:20
Forecaster: SCHLENCZEK

SYNOPSIS

An upper trough over France will dig southward, affecting the Balearic Islands in the evening. Northwesterly 65 m/s jet streak over the east Atlantic is forecast to translate southeastward. Its left exit region should be located over northeastern Spain / the Balearic Islands later in the period. A cold front is stretching from northwestern Portugal towards northwestern Germany, separating a warm and moist airmass to the southeast from a cool airmass to the northwest. Some instability is forecast over the Benelux countries and southwestern Germany, leading to showers and possibly a few thunderstorms.

In the wake of an upper trough over southeastern Europe, some showers and isolated thunderstorms could also develop over Greece.

DISCUSSION

southern France, northeastern Spain, Balearic Islands

Cold upper airmass should overspread the region in the late afternoon / evening, leading to a few hundred J/kg of CAPE where strong QG forcing should allow thunderstorm initiation. Wind fields at lower and mid levels are almost perpendicular to the frontal boundary and convective cells should occur more discrete. Strong 20 m/s deep layer shear as well as enhanced SRH around 100 - 300 J/kg are favourable for organized multicells, some of them may develop rotating updrafts. Isolated large hail is not ruled out but the severe threat should stay below the level one threshold at the moment. An upgrade may be issued if indeed strong convective cells develop.

Bay of Biscay, English Channel, southwestern UK

Cold air convection in a maritime polar airmass is expected over western Europe. Showers and thunderstorms are forecast but weak vertical shear as well as rather weak forcing should preclude severe weather.