Storm Forecast
Valid: Sun 17 Oct 2010 06:00 to Mon 18 Oct 2010 06:00 UTC
Issued: Sat 16 Oct 2010 21:32
Forecaster: SCHLENCZEK

A level 1 is issued for parts of the C Mediterranean, Greece, Ionian / Aegean Sea, W Turkey and S Balkans mainly for severe wind gusts and excessive precipitation and to a lesser extent for large hail and tornadoes.

SYNOPSIS

The blocking upper ridge over the E Atlantic will persist through the period and the main feature for convective activity is a large upper trough over the southern / eastern parts of Europe. Its core should be located over SE France / Switzerland on Sunday morning and should move southward into the Gulf of Genoa. With this upper trough, cold arctic air is advected into most parts of northern and central Europe, resulting in wintery conditions above 800m ASL. Besides some isolated showers and weakly electrified thunderstorms, no convection is expected in the northern half of Europe. The highest probability of a severe convective event should be expected over the southern Balkans / central Mediterranean.

DISCUSSION

...Central Mediterranean towards Greece and Bosporus region...

Warm and unstable air with 1500 - 2000 J/kg MLCAPE is advected towards Greece. Even though this airmass is strongly capped, convective initiation is expected as an upper vort-max affects this region in the late afternoon / evening hours. In the vicinity of an upper jet streak, deep layer shear should increase to 20 - 25 m/s. Especially over the Ionian Sea and S Greece, a small region with locally enhanced SRH3 is expected. Current thinking is that discrete multicells / supercells will develop first and tend to merge into one or two MCSes that will pose a threat of isolated large hail, severe wind gusts and maybe an isolated tornado as well. The most recent GFS runs show accumulated precipitation sums around 50mm / 12h for parts of Greece and S Balkans which may lead to local flooding. During the night hours, the convection will affect the coastal areas of W Turkey.

...Other regions...

The thermodynamic and kinematic conditions in the other regions are not favourable for severe convective weather. Some lightning may occur over parts of the W / C Mediterranean and the Adriatic.