CONVECTIVE FORECAST
VALID Sun 02 Oct 06:00 - Mon 03 Oct 06:00 2005 (UTC)
ISSUED: 01 Oct 19:01 (UTC)
FORECASTER: DAHL

There is a slight risk of severe thunderstorms forecast across the E Aegean Sea ... E Bulgaria ... E Greece ... SW Turkey.

SYNOPSIS

Intense upper trough over the Aegean region is progged to weaken and move east into central Turkey until early Monday morning. Another fairly intense cut-off low is expected to develop over the NW Mediterranean out of digging longwave trough stretching from France into the Norwegian Sea by Sunday 00Z. Except for weak cyclogenesis over the Aegean/Turkey and the NW Mediterranean ... quiescent conditions will exist over SRN Europe. Otherwise ... two large SFC highs are covering E Europe/Russia and the E Atlantic/W Europe.

DISCUSSION

...Aegean Region ... E Bulgaria ... Turkey...
Mesoscale bands of strong mid/upper winds are expected to continue to rotate about the Aegean cut-off low ... providing favorable mesoscale kinematic environments for severe TSTM evolution. CAPE should be rather sparse as the lapse rates are weakened by ongoing ... extensive convection. However ... CAPE in the range of 500 to 1000 J/kg should be present especially where larger gaps in the clouds will occur. Expect a few severe multicellular storms with imbedded mesocyclones ... capable of strong/severe wind gusts and large hail. Strong 850 hPa flow should provide sufficient vertical shear for low-level rotation of TSTM updrafts ... and an attendant tornado threat ... which should also be supported by low LCL heights and weak/no capping. Greatest threat should exist in the first half of the period before LL shear gradually weakens.

...central Mediterranean ... Italy...
Upstream ... weak CAPE may develop in plume of warm air E of the developing NW Mediterranean upper low and beneath its core over the Gulf of Genoa early Monday morning. DLS at the E side of the low ... where DCVA should be maximized ... will be sufficient for severe TSTMS ... though likelihood and timing of evolution of positive CAPE remains uncertain ATTM. Will thus not introduce a SLGT ATTM ... though an upgrade may be necessary with later outlooks. Given quite strong shear profiles ... damaging wind gusts ... large hail and a tornado or two could occur. Also ... a few waterspouts could occur over the N Ligurian Sea early Monday morning with shallow convection that forms over the relatively warm sea waters in largely barotropic environment. Further north ... widely scattered discharges are possible with shallow cellular diurnally driven convection over west-central Europe in polar air mass. Weak CAPE and shear should limit organized severe threat.

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