Storm Forecast
Valid: Wed 27 Aug 2008 06:00 to Thu 28 Aug 2008 06:00 UTC
Issued: Tue 26 Aug 2008 21:01
Forecaster: GATZEN

SYNOPSIS

A westerly flow is present from northern British Isles to Baltic Sea and southern Russia at the southern flank of low geopotential over northern Europe. A broad ridge extends from Bay of Biscay to central Europe, while two cut-off lows are situated west of the Iberian Peninsula and over Italy. Relatively warm air mass over southern Europe will likely be unstable in the range of the upper trough over Italy, while quite calm conditions are present over most of Europe.

DISCUSSION

Northern Africa

An upper-level jet ejects into northern Africa at the south-eastern flank of a cut-off low. Given easterly low-level winds especially near the coasts, quite strong vertical wind shear will develop in the lowest 3 km (15 m/s) and 6 km (20 m/s) over northern Algeria. Low-level moisture advection from the Mediterranean and some low-level forcing along the Atlas mountains is forecast, and thunderstorms are forecast during the afternoon. Given favourable veering profiles supercells may develop capable of producing large or very large hail. There is also a threat of severe wind gusts given dry elevated mixed layer.

Balkans

East of the Italian trough, a south-westerly jet affects the Balkans. Although vertical wind shear will be moderate (15 m/s 0-6 km vertical wind shear), favourable veering profiles will likely support organized convection, and locally large hail is forecast.