CONVECTIVE FORECAST
VALID Wed 14 Dec 09:00 - Thu 15 Dec 06:00 2005 (UTC)
ISSUED: 14 Dec 08:49 (UTC)
FORECASTER: GATZEN

There is a slight risk of severe thunderstorms forecast across southern Aegean Sea region

SYNOPSIS

Strong high present over northern Atlantic. To the east ... long-wave trough is placed over Europe. Intense arctic trough ejects into the long-wave trough over Scandinavia during the period. Over Mediterranean ... intense cut-off low accelerates northeastward and merges to the main European trough. At lower levels ... cold airmass is present over most of Europe spreading into central Mediterranean in the wake of the cut-off trough. At its eastern/northern flank … relative warm airmass is present.

DISCUSSION

...Eastern Mediterranean...
Cut-off low moving from south-central Mediterranean into Aegean Sea has been the focus of convective activity on Tuesday. Thunderstorms that formed where well-organized and have reached southwestern Greece, and Crete. At the southeastern flank of the cut-off … strong upper jet streak will reach southern Aegean Sea and western Turkey during the day … leading to strong QG forcing. At lower levels … warm airmass that spreads northward ahead of a cold front occlusion is characterized by rather steep mid-level lapse rates and relatively rich low-level moisture as indicated by latest Brindisi ascend, while warm airmass east of the front is quite stable indicated by latest sounding data over Greece. During the period … thunderstorms should go on initially along and west of the cold front occlusion and spread into southern Greece, southern Aegean, Crete, and southwestern Turkey. Later in the period … warm and quite stable airmass spreads northward, and thunderstorms should weaken. Thunderstorms that form will have a potential to organize given quite strong DLS and enhanced LLS in the range of the frontal boundary. As low-level airmass is quite cool … surface-based thunderstorms ahead and along the frontal boundary seem to be unlikely, while showers and thunderstorms west of the front should be surface-based. Isolated large hail and severe wind gusts should be the most significant severe threat. A tornado or two are not ruled out in the range of surface-based thunderstorms given locally enhanced low-level SRH. Threat should decrease during the period while isolated thunderstorms are expected further east over Turkey and eastern Mediterranean.

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