Storm Forecast
Valid: Mon 22 Jun 2009 06:00 to Tue 23 Jun 2009 06:00 UTC
Issued: Sun 21 Jun 2009 20:11
Forecaster: GROENEMEIJER

+ + + Amended 22 Jun 0600 UTC + + +

A level 1 was issued for central and eastern parts of Romania and Bulgaria, Macedonia, northern Greece and Albania, mainly for large hail.

A level 1 was issued for eastern Serbia, western Bulgaria and Romania mainly for large hail and excessive rainfall.

SYNOPSIS

Monday at 0600 UTC, a large mid/upper low centered over Germany moves southward reaching central Italy Tuesday morning. As the pressure rises in a zone from southern Finland across southern Scandinavia to the British Isles, an easterly flow becomes established across the Northern European Plain. A warm front, initially stretching from eastern Hungary to Minsk, moves westward as a result. An elevated mixed layer is present across the eastern half of the Balkans. Ahead of a vorticity maximum across Albania and the Ionean Sea, which moves eastward, the surface pressure drops across central parts of the Balkans.

DISCUSSION

Balkans...

At the start of the forecast period, storms are expected to be ongoing across southern Bosnia, Montenegro, southern Serbia, Macedonia, Albania, and NWrn Greece. They should develop northeastward as the forcing associated with the vorticity maximum translates eastward.

It is expected that MLCAPE will rise to values over 1000 J/kg in the pre-convective air-mass during the day. Deep-layer shear should be on the order of 15 m/s, which is sufficient for well-organized multicells, and perhaps a couple of rotating storms. The storms should be capable of producing large (2-5 cm) hail. Additionally, some strong, but mostly sub-severe, wind gusts are possible.

During the afternoon, storms are likely to develop across the central and eastern parts of Bulgaria and Romania, and in NErn Greece and, possibly, European Turkey. Across eastern Serbia, western Romania, they are expected to cluster rapidly into large (partly-)convective clusters. These may cause excessive rainfall in places, as northward-moving storms train over the some areas. The storms will likely continue in through the evening and night, but the large hail threat will diminish a bit due to a reduction of instability.