Storm Forecast
Valid: Sat 11 Sep 2010 06:00 to Sun 12 Sep 2010 06:00 UTC
Issued: Fri 10 Sep 2010 21:04
Forecaster: SCHLENCZEK

A level 2 was issued for parts of Greece and S Albania mainly for widespread excessive convective rainfall and flooding and to a lesser extent for large hail and severe wind gusts.

A level 1 was issued for Greece, S Balkans and S Italy mainly for excessive rainfall and to a lesser extent for large hail and severe wind gusts.

SYNOPSIS

The dominant feature on Saturday is an upper cut-off low over the S Adriatic, slowly translating eastwards. 500 hPa temperatures around -15°C and 850 hPa temperatures around 10°C will lead to some low-end instability in a region with weak upper level winds. The northern edge of this low will affect parts of Hungary and Romania.

A strong upper trough over the NE Atlantic will shift eastwards towards the British Isles, leading to cold air convection over Ireland and parts of UK. The cold front of this low pressure system seems to be not very active on Saturday but this may change on Sunday. Isolated showers and weakly electrified thunderstorms are well possible but severe weather should be unlikely.

DISCUSSION

...S Italy, Balkans, Greece...

Scattered showers and thunderstorms should develop during the daytime with a low potential of hail and gusts. The main threat in parts of S Italy, Albania and Greece is heavy convective precipitation and flooding in the mountaneous areas caused by numerous storms which will make landfall during the afternoon / evening hours. The region where the most intense rainfall is expected is covered with a level 2.

...Hungary, W Romania...

After a period of intense convective rainfall during Friday, the unstable airmass will remain in this region with weak upper level winds and high PWAT. Locally, very intense rainfall is expected with training storms and flooding is possible. Isolated large hail should be possible as well as strong gusts.