Storm Forecast
Valid: Sun 22 Mar 2015 06:00 to Mon 23 Mar 2015 06:00 UTC
Issued: Sun 22 Mar 2015 04:24
Forecaster: TASZAREK

A level 2 was issued for parts of S Italy mainly for large hail, tornadoes, severe wind gusts and excessive precipitation

A level 1 was issued for Tyrrhenian and Ionian Sea, and S Italy mainly for large hail and excessive precipitation

SYNOPSIS

Weather in Europe is mainly dominated by ridge with axis from British Isles to Poland and high over E Mediterranean that inhibit convection. Broad low pressure zone occurs over central and W Mediterranean. W, E, SE and NW Europe is covered with polar air, while intrusion of cold arctic air penetrates NE Europe. Convection will be the most likely in the central and W Mediterranean where warm and moist unstable air is present. Within this area, jet streak and thus significant wind shear will extend from Tunisia to Greece.

DISCUSSION

...Central Mediterranean...

The best conditions for DMC and severe convective storms occur around Tyrrhenian and Ionian Sea, and S Italy where moist air (mixing ratio ~ 10 g/kg) overlaps with steep lapse rates (~ 7.5 C/km). Such combination provide thermodynamic instability up to 1000 J/kg and with DLS exceeding 20 m/s create threat for supercell thunderstorms that can be capable of producing large hail, severe wind gusts and excessive precipitation phenomena. Level 2 area denote area where favorable QG-forcing, DLS and CAPE provide the highest threat for severe convective storms. Within this zone, enhanced LLS create also risk for supercellular tornado occurrence. Increased wind shear in the 0-3km layer indicate also that convection can organize into linear feature highlighting threat for severe wind gusts of convective origin. The highest threat is expected to occur between 1200 and 1800 UTC. Limitations within level 2 are associated with uncertain extent of intrusion of warm and dry air from Sahara that may inhibit convection. Secondly, forecast hodograph indicate lack of vertical directional wind shear that somewhat decreases the risk of severe convective phenomena.