Storm Forecast
Valid: Mon 28 Feb 2011 06:00 to Tue 01 Mar 2011 06:00 UTC
Issued: Mon 28 Feb 2011 11:54
Forecaster: DAHL

A level one threat has been issued across the Ionian Sea for marginally severe wind gusts, hail, and tornadoes.

... SYNOPSIS ...

Dominant feature this period is a rather extensive upper low, centered over the NW Mediterranean Sea early Monday morning. This feature will slowly migrate south- and eastward during the period, instigating weak cyclogenesis over the south-central Mediterranean late on Monday.
Otherwise, high pressure is sprawling across much of the forecast domain, maintaining hostile conditions for deep convection.

... DISCUSSION ...

... Ionian Sea ...

It seems that increasing southerlies in the lower atmosphere over the S-central Mediterranean will advect steep lapse rates across the region. This should be accompanied by an increase of CAPE over the Ionian Sea and to its south late in the period.

Low-level and deep-layer shear (> 10 and > 20 m/s, respectively) should in general be sufficient for storm organization ... although instability and low-level forcing should be somewhat meager.

Expect that the majority of the cells will struggle to organize, but a few cells may evolve into line segments or may become mesocyclonic, which could result in some hail, marginally severe wind gusts and even a tornado or two given strong low-level buoyancy, strong low-level shear, and low LCLs.

The severe threat should develop after about 18 UTC and gradually increase through the remainder of the period.

... western Mediterranean ...

Beneath the upper low, scattered showers and thunderstorms will likely develop/persist. Strong low-level buoyancy is anticipated, so that a few waterspouts cannot be ruled out, although the background flow is rather strong, which may be detrimental to waterspout formation. The overall severe threat should thus be rather low.