Storm Forecast
Valid: Wed 02 Apr 2008 06:00 to Thu 03 Apr 2008 06:00 UTC
Issued: Tue 01 Apr 2008 22:20
Forecaster: GATZEN

SYNOPSIS

Low geopotential is present over Europe east of a ridge from Iberian Peninsula to Iceland. Another polr trough is forecast to amplify over centrl Europe and will cut-off into north Mediterranean later on. A short-wave trough present over west Mediterranean accelerates north-eastward ahead of approaching polar trough and associated jet streak.

DISCUSSION

Aegean

Air mass over south Aegean has become unstable as indicated by latest ascend over Crete. While boundary-layer moisture has increased below a weak inversion, steep low-level lapse rates have developed in the lowest 200 hPa. On WED, this air mass is forecast to spread northward ahead of the approaching upper trough and asociated mid-level jet streak. QG forcing is forecast to be sufficient for initiation, and showers and thunderstorms will likely develop in the range of a surface convergence shown by latest GFS model run. Thunderstroms that will form may merge to clusters, but given rather weak vertical wind shear in the range of the trough center, severe thunderstorms are not forecast.

Adriatic, central Italy

As the upper trough with steep mid-level lapse rates and associated cold front reach the Adriatic region, latest model output indicates that CAPE will quickly develop due to daytime heating as well as over the sea surface. Current thinking is that thunderstorms will develop especially along the propagating cold front, spreading southwards during the day. While most thunderstorms will be affected by weak vertical wind shear, and severe weather is not likely, thunderstorms that form over central Italy will be influenced by the upper jet streak. Well-developed multicells/bowind lines may form, capable of producing isolated severe wind gusts and large hail. Mesocyclones are not ruled out, and isolated toenadoes may develop. Limiting factor will be rather weak low-level moisture and vertical wind shear.