Storm Forecast
Valid: Tue 11 Sep 2012 06:00 to Wed 12 Sep 2012 06:00 UTC
Issued: Mon 10 Sep 2012 21:32
Forecaster: KOROSEC

A level 1 was issued for eastern France, south-central Germany, Switzerland, W Austria into W Czech Republic and Poland mainly for strong to severe wind gusts, excessive convective rainfalls and marginal hail.

A level 1 was issued for NE Algeria and N Tunesia mainly for large hail and severe winds.

SYNOPSIS

A large potent trough progressing east across N-CNTRL Europe during the forecast period with a SFC cold front extending from S Scandinavia across central Europe towards western Alps. This will be the main focus for convective activity on Tuesday. Elsewhere, some daytime driven storms are also expected across complex terrain of central Italy and western Balkans as moisture recovery helps to improve instability there.

DISCUSSION

... central Europe and surroundings ...

A cold front, located rougly NE-SW oriented from Denmark towards southern France in the morning hours, will slowly progress eastwards and serve as a focus for convectve activity during the day into evening hours. QG forcing will provide enough ascent to release storms along the frontal boundary from eastern France into western Germany from late morning while spreading east in the afternoon hours. Marginal instability overlaps with moderate 15-20 m/s deep layer shear which should favour organized severe storms, capable of producing strong to severe wind gusts and marginal hail locally. High PWAT values could also support some intense rain with flash floods.

... Algeria and Tunesia ...

Quite strong instability should release again given the moist low levels with EML atop of it. With moderate shear in place, organized storms with main threat as severe hail and damaging winds are expected. Storms will be daytime driven and will diminish towards the evening when instability vanishes.