Storm Forecast
Valid: Thu 28 Sep 2006 06:00 to Fri 29 Sep 2006 06:00 UTC
Issued: Thu 28 Sep 2006 07:17
Forecaster: DAHL

SYNOPSIS

Broad westerly upper flow is present over Europe ... with several eastward moving perturbations imbedded. Large-scale Atlantic upper low will slowly continue eastward track ... reaching the British Isles and W continental Europe late in the period. The Atlantic upper feature is accompanied by a strong and extensive SFC low ... which is covering the British Isles ... NW-central Europe and parts of Scandinavia. Weak SFC low persists over the S Balkans/Aegean region.

DISCUSSION

Aegean region

Latest soundings from the Aegean region reveal partly strong CAPE ... minimal LL capping ... low LCL heights and rather vigorous shear (ref. LGAT and Izmir 00Z ascents) ... which should exist through much of the day ... with GFS suggesting 10 to 15 m/s LLS and 20 to 30 m/s DLS. All this suggests that supercells are likely ... which may well become tornadic given favorable LL thermodynamic and kinematic support. Also ... large hail and severe wind gusts may occur. Uncertainty on the extent of e.g. the LGAT-00Z-environment ... and indications that such favorable fields exist only on rather small spatio-temporal scales ... are precluding a level 2 ATTM.

Farther W over the Ionian Sea ... CAPE and shear should remain fairly weak ... but LL kinematic profiles suggest that isolated waterspouts may occur. Coverage should be too low for a kategorical risk though.

N Portugal ... NW Spain

NW Spain and N Portugal could see isolated ... likely elevated TSTMS early Friday morning amidst WAA regime ahead of frontal wave ... but it seems that TSTM coverage will remain too low to warrant a TSTM area.