Storm Forecast
Valid: Fri 03 Feb 2012 06:00 to Sat 04 Feb 2012 06:00 UTC
Issued: Fri 03 Feb 2012 00:48
Forecaster: TUSCHY

A level 1 was issued for parts of the CNTRL Mediterranean, including the Tyrrhenian/Ionian and parts of the Adriatic Sea and Sicily mainly for isolated large hail, strong to isolated severe wind gusts and locally heavy rainfall amounts. A tornado or two are possible, too.

SYNOPSIS

Impressive high pressure area over Russia and attendant ridging towards the SW result in unusually cold conditions over most parts of Europe. Embedded cold-core lows may locally enhance the risk for sporadic thunderstorm activity (e.g. S/SW-Baltic Sea, where stronger convection signals may indicate an increased chance of well organized/electrified bands of snow showers (lake effect snow)). Otherwise the air mass remains too dry for any deeper updraft event.

A depression evolves along the southern fringe of that cold air mass. The center becomes more distinct atop the Tyrrhenian Sea while moving slowly to the east. Numerous thunderstorms are forecast beneath that feature. Despite that convective risk, the main hazard likely arises along its northern fringe over parts of Italy and the Balkan State, where significant snowfall/icing probably creates life threatening conditions, next to damaging katabatic winds along the NE and E coast of the Adriatic Sea. All that is not covered in our risk scheme and hence it won't be reflected in that outlook.

DISCUSSION

... Parts of the Mediterranean, including Sardinia, Sicily, the Ionian,Tyrrhenian and Adriatic Sea and adjacent areas ...

A gradually consolidating depression moves slowly to the east and affects those areas all day long. The main picture is pretty messy with modest CAPE/shear present over a broad area and numerous forcing foci forecast. Hence, scattered thunderstorms are expected, which may become widespread over the Ionian Sea and the S-Adriatic Sea during the evening hours onwards. We think that clusters of organized convection affect the highlighted area with isolated large hail, strong wind gusts and heavy rainfall expected. Can't exlude an isolated tornado event with complex flow pattern on the meso-gamma to -beta scale. Highest background helical flow is forecast from Sicily towards S-Italy next to somewhat better LL CAPE, so right now this region will be the focus for a tornado event or two. Thunderstorms gradually decrease west of Sicily during the day as cold front progresses southwards but flare up again after midnight as mid-level temperatures keep falling.

With the surface depression deepening atop the Tyrrhenian Sea, persistent influx of moisture occurs towards the E/SE coast of the Adriatic Sea. Some CAPE is forecast as far north as the central Adriatic Sea. Also, low-end thunderstorm probabilities were expanded a bit onshore along the SE-coast of the Adriatic Sea with marginal elevated CAPE forecast. This may increase the risk of significant icing/snowfall amounts within that area. Models agree well in two QPF maxima, one over Bosnia and Herzegovina/Montenegro and the other one over SW-Italy as a deformation zone sets up. Hence the level 1 was nudged northwards a bit (e.g. between Rome and Naples).