Storm Forecast
Valid: Mon 15 Nov 2010 06:00 to Tue 16 Nov 2010 06:00 UTC
Issued: Sun 14 Nov 2010 22:17
Forecaster: DAHL

A LVL1 was isued across the western Mediterranean Sea mainly for damaging wind gusts.


... SYNOPSIS ...


Main feature of intrest this period will be the western-European
long-wave trough which will slowly close off into a cut-off low over the western Mediteranean while slowly progressing eastwards. A well-defined low-level cold front is associated with this trough, probably stretching from the western Mediterranean across E France and SE Germany into the Baltics early on Monday. Along this boundary, cyclogenesis is simulated to occur over the W Mediterranean late Sunday night and early Monday. The resulting SFC low will affect the western and northern parts of the Mediterranean on Monday and will be a focus for potentially severe convective evolution.
A weakening quasi-stationary upper low perists over the Aegean regions and the S Balkans and should also sustain some deep convection in this region.

... DISCUSSION ...

The air mass over the western Mediterranea ahead of the cold front/upper trough is anticipated to undergo some destabilization, so that weak CAPE should result. Rather decent forcing for upward motion should allow for scattered thunderstorms to form. There should exist a band of 20 - 30 m/s deep-layer shear, overlapping with part of the region of convective avticity. It seems that the thermodynamic support will be quite weak and that storms may remain somewhat shallow. Still, convection may organize into line segments and/or mesocyclones. The primary threat should me marginally severe wind gusts. However, some hail and maybe a brief tornado cannot be ruled out.
In the WAA regime N of the SFC low, large amounts of precip are simulated, but it seems that this will be tied to strong mesoscale ascent, with a limited contribution from deep convection.

In the wake of the cold front, scattered cellular convection should form over the W Mediterranean late on Monday. Though a rather strong background flow is anticipated, a few waterspouts cannot be discounted given rather solid low-level buoyancy.

Scattered storms should persist over the Aegean region, the S Ionian Sea and the SE Mediterranean in association with the weakening upper low. GFS advertises a band of enhanced mid-level flow that may maintain some 15-20 m/s deep shear
over SW Turkey and its SW coast. It seems that an isolated severe wind gust and/or large hail could occur.
Over and S of the Aegean regions, an few waterspouts may occur. However, the overall severe probabilities seem to be too low for a categorical risk.