Storm Forecast
Valid: Tue 27 Feb 2007 06:00 to Wed 28 Feb 2007 06:00 UTC
Issued: Tue 27 Feb 2007 02:54
Forecaster: VAN DER VELDE

SYNOPSIS / DISCUSSION

Steep low/mid level lapse rates within a longwave upper trough and low surface pressure area over the southern Balkan create deep instability over a large area of the Mediterranean Sea today. During the evening deep shear increases to 20 m/s over the area east of Crete, slightly overlapping the unstable air mass and strong low level convergence (as in GFS), increasing the chance of marginally large hail. The rest of the thunderstorm area sees only weak shear. Most forcing is forecast over Greece, Aegean Sea, northeastern Libyan coast, and the Turkish south/west coast, where most organized storms should form, while isolated thunderstorms may occur elsewhere. Low-level shear is enhanced over Turkey, but mostly ahead of instability. Although marginally large hail and a tornado could occur, it does not seem to warrant a threat area.

Ireland is affected twice by unstable airmasses, during the afternoon and near the end of the period. Strong low-level shear (and gusts) will be present over land, but instability is forecast to occur behind a mid level shortwave trough in downward QG motion, so chances of organized convection are slim. An isolated tornado occurrence is not ruled out though.