Valid: Sat 11 Nov 2017 06:00 to Sun 12 Nov 2017 06:00 UTC
Issued: Sat 11 Nov 2017 01:16
A level 1 was issued for CNTRL Mediterranean mainly for large hail, severe wind gusts, excessive precipitation and in lesser extent for tornadoes.
An eastwardly moving broad low covers most of N Europe. Ridges are located over SW and SE Europe while a shallow cut-off is placed between them over S-CNRL Mediterranean. Jet stream stretches from N Atlantic through British Isles, CNTRL Europe and up to W Russia. Pockets of enhanced boundary layer's moisture are located over France, S Italy, CNTRL Mediterranean and Aegean Sea. Thunderstorm activity on Saturday will be located in two areas. First within a cold sector and steep lapse rates on the W and S flank of trough centred over Baltic Sea. Rather poor boundary layer's moisture will limit CAPE to maximum of 200-300 J/kg. Low-topped convection with a discreet mode and small potential for lightning and severe weather is expected to develop throughout forecast period. Second area with thunderstorm activity is within approaching cut-off over CNTRL Mediterranean. Within MIXR of 10-12 g/kg and EML from N Africa with >7.5 K/km ML CAPE develops up to 1500-2000 J/kg. Increasing horizontal geopotential gradients provide 20-25 m/s flow at 500 hPa providing a good source of vertical wind shear. In addition to these ingredients, PVA lobes support CI. Multicell clusters and supercells may be capable of producing large hail (especially given very steep lapse rates), severe wind gusts and tornadoes (given enhanced LLS and SRH), most likely in the morning and around noon hours. Later, although storm activity will continue, severe weather potential should drop. PW exceeding 30mm and training storm mode may result in a local excessive precipitation events over S Italy. Heavy rain and local flash flooding events by superimposing stratiform and convective precipitation also cannot be ruled out over SW Albania and W Greece.