Storm Forecast
Valid: Sun 04 Nov 2007 06:00 to Mon 05 Nov 2007 06:00 UTC
Issued: Sat 03 Nov 2007 20:03
Forecaster: DAHL

SYNOPSIS

Main feature/process of interest will be the merging of the digging NE European long-wave trough and of the Mediterranean upper low, which will result in an intense SWLY upper flow and provide rather strong large-scale ascent over the south-central Mediterranean and the Agean region. Plume of steep mid-level lapse rates is expected to persist over this region, resulting in moderately strong CAPE, partly exceeding 1500 J/kg. Otherwise ... large-scale SFChigh pressure area and/or dry continental polar air masses prevail over Europe.

DISCUSSION

... south-central Mediterranean Sea ... Aegean region ...

Based on Saturday's 12Z ascents and latest model data it seems reasonable to anticipate MLCAPEs in excess of 1500 J/kg to persist across the south-central Mediterranean and the S Aegean region on Sunday. Deep shear is simulated to remain in excess of 20 m/s, increasing to 25 to 30 m/s in the afternoon and evening hours.

Scattered storms should continue during the period, and given gradually increasing DCVA-related upward vertical motion, storm coverage should also increase, especially late in the period towards early Monday morning.

Dominant convective mode will be multicells which should become increasingly well organized during the evening/night. Also, isolated mesocyclones are possible. Expect severe wind gusts along with large hail with the strongest cells. Low-level shear will not be extraordinarily high but could, with 7 to 10 m/s, suffice for supporting strong low-level mesocyclogenesis, especially as the boundary layer will be nearly saturated, resulting in an enhanced threat for tornadoes.

Currently, it seems that a clear low-level mesoscale focus for ascent is lacking and that severe storm coverage may remain somewhat low. Will thus only introduce a level-one threat though an upgrade to level two may be considered on Sunday.