Storm Forecast
Valid: Wed 04 Feb 2015 06:00 to Thu 05 Feb 2015 06:00 UTC
Issued: Tue 03 Feb 2015 22:29
Forecaster: PUCIK

A level 1 was issued for Sardegna, Corsica towards western Italy coastline mainly for excessive precipitation, severe wind gusts and to the lesser degree for tornadoes.

A level 1 was issued western Adriatics coastline mainly for excessive precipitation and to the lesser extent for severe wind gusts.

SYNOPSIS

An extensive pool of low gepotentials covers much of Europe with numerous embedded separate low centers and troughs. However, rather stable and dry airmass will dominate over the continent, with most of the convective activity occurring over the Mediterranean. Cyclonic vortex is forecast to translate from Iberia towards the W Meditteranean Sea and N Africa. At the same time, SW-ly jet-stream will spread over the Balearic, Tyrrhenian Sea and parts of the W Italian coastline. This region will experience scattered thunderstorm activity and is discussed more below. Isolated to scattered thunderstorms will also occur over the parts of the Adriatic Sea.

DISCUSSION

... Sardegna, Corsica, Tyrrhenian Sea towards central-western Italy...

Under the left exit region of jet-streak at mid to upper troposphere, surface low will start deepening over the Balearic Sea. During the day, it will move eastwards in accordance with the position of the jet-stream. Left exit region will cover the Tyrrhenian Sea and western Italy coastline on Thursday between 00 and 06 UTC. At the same time, southerly flow on the forward flank of the surface low will advect moister airmass towards the region. With moistening of the low-levels and advection of steeper lapse rates atop, CAPE values on the order of hundreds J/kg are forecast over the sea and coastal regions. Moderate to strong degree of vertical wind shear is forecast as well, especially in the zone of the jet-stream, where DLS values will be above 20 m/s.

Primary threat will be excessive precipitation, especially towards the Thursday morning hours. Furthermore, with strong LLS in the coastal areas and 850 hPa windspeeds over 20 m/s, severe wind gusts or a tornado event are possible.

... parts of the Adriatics coastline ...

A Wednesday morning passage of the trough over the region should result in scattered DMC activity, enhanced by strong low-level flow impinging on the steep coastline terrain. Despite rather marginal CAPE values, local excessive precipitation event is possible, along with severe wind gusts with 850 hPa flow over 20 m/s. The first round of DMC is forecast between 06-12 UTC, the second one towards Thursday morning with the approach of another system.