Storm Forecast
Valid: Tue 16 Aug 2011 06:00 to Wed 17 Aug 2011 06:00 UTC
Issued: Mon 15 Aug 2011 23:00
Forecaster: KOROSEC

A level 1 was issued for central Sweden mainly for strong wind gusts, brief funnel/tornado and locally excessive convective rainfall.

A level 1 was issued for the Baltics, extreme NNE Ukraine, E Belarus into W Russia mainly for excessive convective rainfall, large hail and strong wind gusts.

SYNOPSIS

A ridging pattern is establishing across the south-central Europe and a long-wave trough over NE Atlantic sea. A weak short wave trough moves across the Baltic sea/States. A frontal system affects central Sweden and Norway. Still low geopotential heights affecting eastern Europe/western Russia with mostly daytime driven activity. Elswhere, developing heat wave with strong capping preclude deep convection except some isolated storms near the local complex topography over Italy and S Balkans. A SFC front continues to weaken while moving across the central Balkans with almost no shear and only marginal instability available, so severe activity is unlikely there.

DISCUSSION

... central Sweden ...

A short-wave trough makes progress more to the north with a SFC cold front pushing NE-wards across the central Scandinavia. Models simulate marginal instability and moderate near 15-20 m/s of deep layer shear overlaping over central Sweden. Quite some forcing should initiate scattered showers and thunderstorms during the peak heating hours and they should gain some organization into a few multicells. Quite high 0-3km and LL shear seem supportive of some rotation updrafts as well, so a brief funnel/tornado cannot be completely ruled out either. A marginal level 1 has been issued for these areas.

... the Baltics, extreme NNE Ukraine, E Belarus into W Russia ...

These areas will be again affected by the weak upper low and also by the eastward moving weakening cold front. Airmass remains highly unstable with rich BL/troposphere moisture content and very low shear. Therefore widespread pulse storms are expected, bringing mostly excessive convective rainfall threat. Stronger cells might bring some hail and strong wind as well. Slightly better overlaping with some shear seem across the Baltic states as upper trough approaches from the west. There some more organized storms can be expected.