Storm Forecast
Valid: Sun 13 Aug 2006 06:00 to Mon 14 Aug 2006 06:00 UTC
Issued: Sat 12 Aug 2006 23:23
Forecaster: DAHL

SYNOPSIS

Large-scale upper low remains anchored over central portions of Europe ... exhibiting quite intense perturbations at its southern periphery ... one of which will rotate across the central Mediterranean into the eastern Balkans on Sunday/Sunday night ... the other ove affecting E-central Europe. Warm/moist air mass is present over the SRN Mediterranean ... and is advected northwards into the Balkans and E-central Europe E of the disturbances ... favoring SFC cyclogenesis over Poland.

DISCUSSION

S Italy ... west-central Balkans

It looks that quite some severe potential exists ahead of the Mediterranean vort max over S Italy ... the Adriatic Sea and the Balkan States. Though it does not seem that the entire region will be overspread by Iberian EML ... at least the southern portions of the Adriatic Sea and the S Balkans may profit from it ... but in general CAPE should only be on the order of 1000 J/kg ... with somewhat higher values expected farther S over the Ionian Sea.

Shear profiles will be quite decent per latest model guidance ... with 25 to 30 m/s 0-6 km shear ... and 10 m/s 0-1 km shear ... providing favorable kinematic support for organized severe storms ... including supercells.

Strong forcing for upward vertical motion should accompany upper vort max and the associated SFC cold front crossing the area during the period ... and rather widespread TSTM development is anticipated. Southward extension of TSTM activity is somewhat uncertain ATTM ... but capping seems to be too strong for widespread activity over Greece and the Ionian Sea. However ... TSTMS forming over the latter areas should benefit from stronger thermodynamic support than the bulk of the TSTMS farther north.

Expect entire fascet of severe weather ... large hail ... damaging straight-line winds and tornadoes. Models do not advertise appreciable CAPE over the Balkans in the evening/night hours ... but given already moist BL's ... LL warm/moist advection and vigorous forcing for ascent ... TSTM activity should persist along the front into the late evening/night hours.

E Poland ... SW Belarus ... W Ukraine

Chance for a few severe TSTMS should exist over E Poland and the Belarus in the afternoon and evening hours where larger gaps in the clouds occur. LLS of 12 m/s ... and DLS in excess of 25 m/s should be supportive of mesocyclonic storms ... capable of producing ... large hail ... severe wind gusts and a few tornadoes. However ... SFC-based convective development may be suppressed by thick cloud deck/stratiform precip. Nonetheless ... chances for scattered mesocyclones appear to be marginally sufficient for a level-one threat.

W-central Europe

Otherwise ... organized severe threat is rather low ... though steep low-level lapse rates will remain in place over central portions of Europe in the polar air. Any Cu/Cb interacting with pre-existing miso-vortices will thus have fair chances of producing a water/landspout ... which may well be associated with weakly/non-electrified convection. Allover threat should be too low for a categorical risk, however.