Storm Forecast
Valid: Sat 14 Apr 2018 06:00 to Sun 15 Apr 2018 06:00 UTC
Issued: Fri 13 Apr 2018 21:32
Forecaster: TASZAREK

A level 1 was issued for NE Algeria and Tunisia mainly for the large hail, severe wind gusts and excessive precipitation.

SYNOPSIS & DISCUSSION

Pressure field over Europe is diversified but it does not create a good overlap of instability and shear - a mixture conducive for severe thunderstorms. Broad ridge covers SE and parts of E Europe. Small high is placed over SW Scandinavia. Troughs are located over France and N Germany. Low is approaching British Isles. Well-developed cut-off travels NEwardly through Algeria, Tunisia and S-CNTRL Mediterranean. Jet stream surrounds W and E flanks of the cut-off. Rich BL's moisture covers Balkan Peninsula, a corridor from Lithuania to CNTRL Romania, N France and S Mediterranean. Within the support of a diurnal heating a rather small instability (ML CAPE ~ 400-800 J/kg) develops over aforementioned areas and thus weakly organized thunderstorms are expected. The highest chances for CI involve N France where a shortwave trough will occur in the afternoon hours. Isolated to multicell thunderstorm activity may locally cause excessive precipitation and severe wind event but the overall threat is too low to issue lvl. 1 for this area. Isolated storms are also possible over Balkan Peninsula and parts of E Europe, but overall chances for CI are low, mostly due to lack of a sufficient synoptic-scale lift. Better organized storms are expected within cut-off over Algeria and Tunisia where steep lapse rates and highly sheared environment will be available. Multicell clusters and supercells developing in the afternoon hours under the support of the strong diurnal heating, rich BL moisture and steep lapse rates may be capable of producing large hail, severe wind gusts and excessive precipitation. In the late evening and nighttime hours, thunderstorms activity should fade over France, E Europe and Balkan Peninsula but is likely to remain over S-CNTRL Mediterranean and Sardegna.