Storm Forecast
Valid: Sun 24 Sep 2006 06:00 to Mon 25 Sep 2006 06:00 UTC
Issued: Sat 23 Sep 2006 22:50
Forecaster: DAHL

SYNOPSIS

W-European upper low will make slow eastward progress ... thereby maintaining the severe weather threat over the W Mediterranean. SE-European upper low is expected to weaken and move eastward out of the forexcast area during the period. At low levels ... weak but extensive SFC low over the E Atlantic is maintaining SLY flow over W and central Europe.

DISCUSSION

western Mediterranean

It seems that very moist low-level air mass is present over the W Mediterranean ... which should spread eastwards ahead of the upper low on Sunday. CAPE in this air mass should be in the 1000 to 2000 J/kg range ... maybe even higher. DLS of 15 to 20 m/s ... should maintain threat for supercells and severe multicells ... primary risks being large hail and damaging wind gusts. Especially in the evening and night hours of Sunday ... LLS is progged to increase to 10 m/s ... which ... coupled with nearly saturated maritime boundary layer ... should support a couple of tornadoes as well. Upscale growth into one or more large nocturnal MCSs is anticipated.

France

Isolated to scattered TSTMS should develop amidst and just W of the warm-air plume over France and the UK. Deep shear should be marginally supportive of a few mesocyclonic storms capable of severe wind gusts and large hail. Especially the storms forming directly W of the baroclinic zone associated with the W edge of the warm air mass ... may profit from strong LLS and will additionally pose a threat for tornadoes. Coverage of SFC-based storms in the favorably-sheared region appears to be rather low however.

Aegean Sea ... SW Turkey

A few severe TSTMS may continue over the S Aegean Sea and the Turkish W and S coast in weakly unstable and moderately strongly sheared environment. LL thermodynamic fields may continue to be favorable ... and may compensate for the weak LLS ... suggesting that a few tornadoes may occur with any supercell that develops. Main threats should be severe wind gusts and large hail, however.