Storm Forecast
Valid: Sat 24 Jan 2015 06:00 to Sun 25 Jan 2015 06:00 UTC
Issued: Fri 23 Jan 2015 19:15
Forecaster: PISTOTNIK

A level 1 was issued for W Greece mainly for excessive convective precipitation and to a lesser extent for waterspouts.

A level 1 was issued for the island of Crete and for N Greece for excessive convective precipitation.

SYNOPSIS

A broad long-wave trough at 500 hPa covers large parts of Europe, topped by a cut-off low over Italy and the Balkans. A new short wave, accompanied by an occluding frontal system, ejects southward from the North Sea across BeNeLux and the western Alps into the west-central Mediterranean and reinvigorates the long-wave trough.
Near the surface, extensive but filling cyclones are situated over the Norwegian Sea and over the Ionian Sea, opposed by high pressure over Russia and over France, the Bay of Biscay and the Iberian Peninsula. Most of Europe is covered by temperature to cool air. The only exception is a withering tongue of mild and moist air ahead of the main trough, which stretches from southeastern Europe and the Black Sea into the western Ukraine and Belarus.

DISCUSSION

... eastern Mediterranean, Greece ...

Cold upper-level air on top of the mild sea surface still creates some hundred J/kg of CAPE in the periphery of the cyclone over the Ionian Sea. However, compared to the past few days, vertical wind shear relaxes notably.
Scattered disorganized storms will go on throughout the forecast period. Training activity with heavy precipitation and isolated flash floods is possible in regions which experience sustained 15 m/s onshore and upslope flow, most notably western Greece and the island of Crete until 21 UTC and the northern Aegean region thereafter. In addition, one or two waterspouts are not ruled out near the center of the cyclone in coastal areas of western Greece and southern Albania.

... central Mediterranean ...

Instability will be less and shallower towards the west, but scattered to widespread shower activity may still produce a little lightning. Severe weather is unlikely.
The arrival of the short-wave trough from the north sparks a new cyclogenesis over the Ligurian Sea in the afternoon, which will move to Sardegna by Sunday 06 UTC. A strong pressure gradient develops along its western flank and severe Mistral winds are expected. However, this strong wind field is not expected to overlap with instability deep enough to produce thunderstorms, and is therefore not reflected by our threat level scheme.