Storm Forecast
Valid: Sat 22 Mar 2008 10:00 to Sun 23 Mar 2008 06:00 UTC
Issued: Sat 22 Mar 2008 09:51
Forecaster: DAHL

SYNOPSIS

Deep and intense large-scale upper trough over central Europe will further amplify while remaining rather stationary, resulting in quite a strong and broad southwesterly mid/upper flow over the eastern portions of Europe and the Mediterranean. Associated low-level baroclinic zone will stretch from the SW Mediterranean northeastwards towards the Ukraine at the end of the period. A weak SFC pressure perturbation is generated over the Gulf of Genoa region during the day, rapidly moving off to the northeast ... while more vigorous cyclogenesis is anticipated off the Iberian east coast ahead of a vort max pivoting around the base of the large-scale trough in the evening hours. This feature will travel towards the Gulf of Genoa region by Sunday 06Z.

DISCUSSION

... southwestern Mediterranean ... Tyrrhenian Sea ... central Italy ... central Adriaric Sea ...

Main focus for potentially severe convective evolution will be the SFC low that travels into the NW Mediterranean during the late evening/night hours while undergoing some strengthening. It seems that instability in the warm sector will remain rather low, with CAPE probably not exceeding a few hundred J/kg. However, GFS suggests that after about 15Z, an increasing juxtaposition of 20 deep-layer shear and CAPE will occur, providing favorable kinematic environment for organized storms. LLS will likewise increase per GFS, which produces 10 m/s over the northern Tyrrhenian Sea at Sunday 06Z. Expect well-organized multicells and a couple of mesocyclones, capable of strong/severe wind gusts, and maybe some marginally severe hail. Enhanced low-level shear suggests that an isolated tornado or two could occur as well. Thunderstorm activity and severe threat should gradually increase during the evening/night, peaking towards early Sunday morning.

... Germany ... France ...

In the deep polar air mass over the European continent, scattered showers which may produce occasional thunder are anticipated near the upper thermal trough region. This activity is expected to bee too insignificant to warrant a thunderstorm area.