Storm Forecast
Valid: Mon 16 May 2011 06:00 to Tue 17 May 2011 06:00 UTC
Issued: Mon 16 May 2011 06:00
Forecaster: DAHL

A level one threat has been issued across southern Italy, the southern Adriatic regions, and the northern Ionian regions mainly for marginally severe winds/hail.

SYNOPSIS

An elongated upper trough extends from central Europe into the northern Mediterranean on Sunday evening. This
feature will continue its process of closing off into a cut-off cyclone. By the end of the period, the remaining
upper short-wave trough will have moved into extreme NW Russia, while the upper low will be centered over S Italy.
Another upper low is residing off the Iberian Atlantic coast. At low levels, plumes of warm/moist air will exist east of the
cut-off cyclones and the attendand weak low-level circulations.

DISCUSSION

... southern Italy ... southern Adriatic and northern Ionian regions ...

It seems that scattered storms will form in association with the developing upper low along and ahead of the
attendant low-level baroclinic zone, aided by diurnal heating. Deep-layer shear should be supportive of severe
evolution across S Italy, the S Adriatic and N Ionian regions. Dominant mode should be multicellular storms/line segments with a
threat of marginally severe wind/hail. Weak instability and somewhat patchy overlap of favorable CAPE/shear should limit
the overall severe threat. A marginal LVL1 seems to be warranted nonetheless.

... southwestern Iberia ...

Scattered thunderstorms should develop over southwestern Iberia in a WAA regime late in the day, which may lead to
one or more possibly elevated thunderstorm clusters in the overnight hours. Shear profiles seem to be rather weak, but
a brief episode of outflow winds/hail approaching severe limits cannot be discounted. The overall severe threat is too low
to necessitate a LVL1 risk.