Storm Forecast
Valid: Wed 26 Sep 2007 06:00 to Thu 27 Sep 2007 06:00 UTC
Issued: Wed 26 Sep 2007 06:03
Forecaster: GATZEN

SYNOPSIS

A very strong cut-off low spreads into noth-west Mediterranean, and cold air mass advects into western Europe. A strong jet streak ahead of this cut-off and associated frontal bondary will affect most of central Mediterranean during the period.

DISCUSSION

Southern Mediterranean to northern Italy

Latest observations show that rich low level moisture is present over souhern Mediterranean, while the moisture is rather weak over the northern regions. Additionally, steep low-level lapse rates are present in the range of the propagating cut-off.

Along the cold front, thunderstorms will likely develop during the day. Given rather strong vertical wind shear, storms may organize especially in the southern parts of the risk area, where several frontal waves are expected. In the afternoon/evening hours, MS development is possible near the African coast. High winds and locally large hail seem to be the main threat.

To the north, best potential for severe thunderstorms estist over northern Italy, where remaining moist air mass and weak low-level winds are expected north of deepening low pressure. Thunderstorms will likely form, but it is not sure wether they will become surface-based generally. Current thinking is that a few mesocyclons will develop, merging into MCSs. Severe wind gusts, locally large hail and maybe a tornado are not ruled out. Convective activity will spread into Blkans later on.