Storm Forecast
Valid: Sun 24 Mar 2013 06:00 to Mon 25 Mar 2013 06:00 UTC
Issued: Sun 24 Mar 2013 06:24
Forecaster: VAN DER VELDE
A level 2 was issued for northeastern Algeria and northern Tunesia mainly for large hail.
A level 1 was issued for Corsica and Sardinia mainly for large hail.
A level 1 was issued for southwestern Italy mainly for a chance of large hail.
SYNOPSIS
North Atlantic blocking high pressure keeps northern Europe under cold weather conditions. The boundary between cold and warm air lies on the line Romania-Ireland. The frontal zone is no longer active. At mid levels western Europe lies under a saddle area. The warm airmass is unstable over parts of France and Iberian Peninsula. The dynamically most active low pressure system lies over the western Mediterranean. It excerts QG rising motions at its east and north flanks, Sardinia, Corsica and Italy. CAPE is small, but moderate deep layer shear is present. The best conditions are found over northeastern Algeria and northern Tunesia.
DISCUSSION
...Corsica and Sardinia....
During the afternoon CAPE should be weakly capped and triggered by low level convergence and upper support from the approaching trough, with a marked PV intrusion. Deep layer shear will be moderate, and an isolated large hail event may occur.
...northeastern Algeria and northern Tunesia...
Large circular GFS model hodographs are in place, representing more than 300 mē/sē of 0-3 km SREH and more than 35 m/s (!) bulk 0-6 km shear. Weakly capped CAPE, although not so much (<500 J/kg), should be converted by strong low level convergence, orography and the incoming trough into supercells bearing large hail.
...western Italy coast...
Early Monday morning the trough will activate convection in this area. It looks as if this may be elevated at first. The same conditions and threat as the Corsica/Sardinia area apply.
