Storm Forecast
Valid: Sun 10 Oct 2010 06:00 to Mon 11 Oct 2010 06:00 UTC
Issued: Sun 10 Oct 2010 05:06
Forecaster: SCHLENCZEK
A level 2 was issued for S France mainly for widespread excessive convective precipitation and to a lesser extent for severe wind gusts and isolated tornadoes.
A level 2 was issued for Sardinia, Corsica, Sicily and for the western half of Italy for excessive precipitation, large hail, severe wind gusts and tornadoes.
A level 1 surrounds the level 2 for excessive precipitation, large hail and severe wind gusts.
A level 1 was issued for N Morocco mainly for excessive precipitation.
SYNOPSIS
Ahead of a low pressure system over the W Mediterranean, a plume of very warm and unstable air over the Mediterranean Sea will affect parts of the central Mediterranean and the Tyrrhenian Sea during Sunday.
Another low pressure system is centered over the Black sea and will lead to unsettled conditions over the SE Balkans and the Bosporus region. Most parts of central and northern Europe will stay under high pressure and stable conditions.
DISCUSSION
...W-central Mediterranean, S France, Corsica, Sardinia, Sicily, the western coastal parts of Italy...
Moderate to high instability (MLCAPE around 2 kJ/kg) and some 15 - 20 m/s deep layer shear are present over the entire level 1 area which includes the level 2 spots. The most important threat for S France, Corsica, Sardinia, Sicily and parts of W-central Italy will be excessive convective rainfall from a slow moving MCS which may exceed easily 150mm / 24h in some places. Moderate to high values of SRH3 (200 - 500 mē/sē) in place with instability and rich BL moisture near Sicily and Corsica may allow some embedded mesocyclones within the MCS and / or isolated supercells which may produce an isolated tornado, even a strong one (F2-F3) is not ruled out. The severe episode will start in the early morning over S France and Sardinia and will reach Italy and Sicily in the late evening / night hours.
...N Morocco...
Less instability (only a few hundred J/kg) are expected for this region but storms which move towards Morocco from the Atlantic should cross this area rather slowly. Combined with a training effect, this will lead to local excessive precipitation.
...Black Sea region...
Isolated thunder should be expected with some rather shallow cold-air convection over the Black Sea. Severe weather is unlikely.
Some isolated flashes cannot be discounted also over NW Norway but confidence is too low for a low probability thunderstorm area.
