Storm Forecast
Valid: Tue 01 Mar 2011 06:00 to Wed 02 Mar 2011 06:00 UTC
Issued: Mon 28 Feb 2011 23:16
Forecaster: KOROSEC

A level 1 was issued for Ionian Sea, southern Italy and southern Mediterranean sea mainly for strong wind gusts, marginally large hail, tornadoes and excessive convective rainfall.

SYNOPSIS

The dominant feature today is an extensive ridge expanding across west-central Europe towards Russia with a large potent upper-level low center over central Mediterranean sea and Tyrrhenian sea. Its SE-wards progression slows down and becomes rather stationary during the forecast period. Surface cyclogenesis takes place in the morning hours and wobbles over the Tyrrhenian sea. Its warm front advects across the Adriatic sea while strong cold front trails NE-wards across the southern Italy and Ionian sea. This front will be the main concern for severe convection/threat today.

Elsewhere, cool and stable conditions will persist throughout the forecast period.

DISCUSSION

... southern Italy, Ionian Sea / southern Mediterranean sea ...

A narrow moist sector characterized by near 10 g/kg mixing ratios will continue advecting NE-wards into Ionian sea ahead of the well-defined surface cold front. Rather strong southerly winds will maintain this airmass under steep lapse rates. As a result, marginal to moderate instability of several hundreds J/kg MLCAPE will result. In the mid levels, quite strong jet will overtake this moist/warm sector and support large scale ascent over the level 1 area. As a result, severe convection/storms become increasingly likely given the overlaping istability with 25m/s DLS and SREH in the lowest levels. Expect organized storms to continue from overnight activity, capable of producing strong winds with marginally large hail and intense rainfalls/flash floods as the primary threats. Favorable hodograph seem enough supportive for tornado threat as well, especially given the quite impressive SREH/shear in the lowest 1km. However, given the storms may become linearly organized along the strong surface convergence, a few supercells may also be embedded in this complex storm system trailing along the surface front.

In the wake of the front across Sicily and westwards towards Tunisian coast, environment should become supportive for a couple of waterspouts as well, given the steep LL lapse rates, weak wind profile and high low-level buoyancy. It seems that scattered showers and thunderstorms will be on going mostly during the daytime hours and should diminish soon after sunset as instability vanishes.


As a side note... A tightening pressure/temperature gradient between slowly deepening surface low over central Mediterranean and expanding high pressure area over east-central Europe, will create dangerous windy conditions mostly along the NE-ern Adriatic coast. Overnight to Wednesday, very strong to extreme Bora winds will evolve across SW Slovenia, northern Adriatic sea and Kvarner bay. Expect strong wind gusts exceeding 45 m/s and dangerous weather conditions.