Storm Forecast
Valid: Mon 19 Apr 2010 10:00 to Tue 20 Apr 2010 06:00 UTC
Issued: Mon 19 Apr 2010 10:26
Forecaster: DAHL

A level 1 was issued across the S Balkans ... the Ionoan Sea ... and the Aegean Sea ... mainly for severe wind gusts and excessive precipitaton.

SYNOPSIS

A large-scale quasi-stationary upper trough is covering most of the European continent ... with a southern-stream impulse moving across the southern Balkans today and tonight. At low levels, the prominent feature is a weak low pressure system attendant to the Balkan vorticity maximum. A rather pronounced low-level baroclinic zone is stretching across the northern portions of central Europe, roughly parallel to the North/Baltic Sea coasts. The air mass south of this boundary is moderately warm/moist and expected to become weakly unstable towards the afternoon hours.


DISCUSSION

... Ionian Sea ... S Balkan ... Aegean Sea ...

Thunderstorms are ongoing over the Ionian Sea and the southern Balkans. Though instability is weak, deep shear in the range of 20 to 25 m/s is sufficient for organized thunderstorms, including linear segments and mesocyclones. Main threat will be severe straight-line winds and magrinally severe hail, as well as locally heavy rain, especially over Bulgaria and S Romania. Initially, low-level shear is marginal per model guidance, but especially early Tuesday morning, 10 m/s LLS are simulated over the E Aegean and W Turkey. Any SFC-based cell will have the potential of becoming tornadic, though the overall threat seems to be somewhat limited given the unfavorable timing.

Elsewhere ... weak CAPE and shear suggest that severe evolution is unlikely.