CONVECTIVE FORECAST
VALID Sun 07 Aug 06:00 - Mon 08 Aug 06:00 2005 (UTC)
ISSUED: 06 Aug 19:16 (UTC)
FORECASTER: DAHL

There is a moderate risk of severe thunderstorms forecast across the central Ukraine and the E Belarus.

There is a slight risk of severe thunderstorms forecast across the Belarus ... the Ukraine ... extreme E Balkan States.

SYNOPSIS

As vigorous and large upper cut-off low becomes established over north-central Europe ... SE-European upper low lifts NEWD across Turkey and the Black Sea. Vort max at W periphery of central-European upper low is progged to dig S ... reaching the N Balkan States late in the period. Plume of moist and moderately unstable air mass persists E of the upper low.

DISCUSSION

...Belarus ... Ukraine...
Nearly uncapped profiles ... featuring MLCAPEs of 1700 to 2000 J/kg have been measured on Saturday 12Z within plume of subtropical air mass over SE Europe. Indications are that these values will be present also on Sunday across the central Ukraine ... gradually decreasing towads the north.

TSTMS should redevelop along and ahead of the cold front over the central Ukraine in the early afternoon hours ... and spread northwards during the period. According to GFS the strongest shear will remain somewhat offset to the W of where the highest CAPE is expected ... but up to 20 m/s DLS may be realized at the WRN portions of the theta-e tongue. Expect mainly severe linear/multicellular storms capable of producing large hail and damaging winds. Over the E Belarus and the N-central Ukraine ... 0-1 km shear is progged to increase late in the day ... per GFS well in excess of 15 m/s. While this may be too aggressive ... threat for supercells and tornadoes appears to exist across this region especially as LCL heights decrease late in the day.

...N-central Europe...
Another round of numerous diurnally-driven small cumulonimbi is expected over central portions of Europe in the vicinity of the center of the upper low. Weak CAPE and weak shear should limit organized severe threat ... however ... steep LL lapse rates and weak LL shear may promote a few spout-type tornadoes. Threat is too low for a SLGT though.

...NW Balkan States...
Vigorous vort max is expected to overspread N Italy and the N Balkans on Sunday evening/night ... though CAPE is progged to be nonexistent within the affected air mass ... a few TSTMS may occur nonetheless. Later radiosonse data need to be awaited ... but an upgrade may be required on Sunday in case air mass destabilizes more than currently anticipated.

#