Storm Forecast
Valid: Mon 12 Nov 2012 06:00 to Tue 13 Nov 2012 06:00 UTC
Issued: Sun 11 Nov 2012 22:05
Forecaster: SCHLENCZEK
A level 2 was issued for N-central Italy mainly for large hail, severe wind gusts and tornadoes and to a lesser extent for excessive precipitation.
A level 1 was issued for the N Adriatic region mainly for excessive precipitation.
A level 1 was issued for the Tyrrhenian Sea and N Algeria / Tunisia for large hail, severe wind gusts and tornadoes.
SYNOPSIS
Between an upper high over central Europe and a cut-off low over N Morocco, a southeasterly LL flow advects very warm and moist air into the central and western parts of the Mediterranean. This will lead to moderate instability over a rather broad area, but most of the convection will remain over water. The remaining parts of Europe will get rather stable conditions.
DISCUSSION
...N Adriatic region...
The torrential rainfall threat for Slovenia and the surrounding countries will also continue on Monday as onshore advection of slightly unstable air with high effective PWAT should be sustained during the whole forecast period. Apart from a heavy rainfall threat, not much severe weather is expected.
...N-central Italy...
Some hundred J/kg of MLCAPE overlap with 15 - 20 m/s of 0-6 km shear and 150 - 200 mē/sē SRH3 over the northern parts of Italy. Current thinking is that some organized multicellular storms and a few supercells will form, posing a threat of large hail, severe wind gusts and tornadoes. It is possible that a big MCS will form like it has happened on Sunday evening, which will push the threat more towards severe wind gusts and heavy rain.
...Tyrrhenian Sea, S - central Mediterranean, N Algeria / Tunisia...
The highest instability is found in the south of the central Mediterranean, extending northwards towards the Tyrrhenian Sea. GFS simulates approx. 2 kJ/kg MLCAPE which partially overlaps with 15 m/s of 0-6 km deep layer shear. High CIN should preclude convective initiation in the southern parts of the area, but isolated thunderstorms may pose a threat of large hail and severe wind gusts. Locally, enhanced 0-1 km SRH and LL shear may allow an isolated tornado as well.
