Storm Forecast
Valid: Sat 08 Jul 2006 06:00 to Sun 09 Jul 2006 06:00 UTC
Issued: Fri 07 Jul 2006 18:47
Forecaster: DAHL
SYNOPSIS
Large-scale upper trough is anchored over the NE Atlantic ... providing the NW European portions with a rather intense WLY/SWLY upper flow ... in which several vort maxima are imbedded. One such vort max is progged to dig towards central France and W Germany late in the forecast period. Otherwise ... weak upper low should travel from S Italy across the Ionian Sea into the Aegan Region ... while another ... somewhat larger upper low lingers over the Black Sea. At low levels ... cyclogenesis is expected ahead of vigorous vort max over Scandinavia ... and another ... Atlantic SFC low should reach the British Isles by early Sunday morning. Otherwise ... quiescent conditions persist at the surface.
DISCUSSION
N Sweden ... NW Finland
It seems that a few severe TSTMS may occur ahead of vigorous vort max over N Sweden and NW Finland. Instability should be quite meager ... but deep shear should increase in the late evening hours ahead of the approaching trough. Also ... cyclogenesis will increase the LL shear. Main concern will be location of the best large-scale UVV's and deep-shear profiles ... it seems that TSTMS will develop E of the main cold-frontal boundary in region of low-level convergence where also the pressure drops will be maximized ... so that bulk of the activity may not benefit from the favorable UVV/shear regime farther upstream. Nonetheless ... it seems that a few marginally sever wind/hail events could occur. Also ... minimal low-level capping and increasing LL shear may support a few bief tornadoes.
S Italy ... Ionian Sea ... Greece
Another focus for potentially severe convective evolution will be weakening upper low over S Italy/Ionian Sea ... CAPE should be in excess of 1000 J/kg ... with deep shear FCST to be on the order or 15 to 20 m/s ... which should be supportive of a few severe multicellular and isolated mesocyclonic storms. Main threats will be large hail and severe wind gusts.
Otherwise ... organized severe TSTM threat should be rather low owing to weak CAPE/shear.
