Storm Forecast
Valid: Wed 11 Jun 2008 06:00 to Thu 12 Jun 2008 06:00 UTC
Issued: Tue 10 Jun 2008 21:59
Forecaster: SCHLENCZEK

SYNOPSIS

Between an upper ridge over the North Atlantic and an upper longwave trough over northern Scandinavia, cold air is advected southward. In the wake of the trough, showers and thunderstorms with a low threat of severe weather will evolve over UK and southern Scandinavia in an environment with low-end instability. An upper level cut off low over the western Mediterranean will affect the Balearic Islands and northern Algeria. On the southern side of a well-defined cold front that stretches from the Baltic States / Belarus via Poland and central Germany towards the Netherlands and western UK, diurnal heating will create moderate instability in the warm and moist subtropical airmass.

DISCUSSION

...Southern France, northern Italy, Austria, Hungary...

During the day, diurnal heating may create 1 - 1,5 kJ/kg MUCAPE in a weakly sheared environment. Even though low level shear is weak, good LL buoyancy and low LCL heights could allow an isolated funnel / brief tornado. Multicell storms may produce isolated large hail and heavy rain may lead to local flooding but a threat level is not warranted at the moment.

...Northern Algeria...

Ahead of an upper trough, warm and moist air at lower levels is advected into northern Algeria by northeasterly winds. A strong 35 m/s jet streak at 300hPa overspreads the region and embedded vorticity maxima provide sufficient QG forcing for deep moist convection. Some hundred J/kg of CAPE combined with 20 - 25 m/s deep layer shear hint at well-organized multicells and a few mesocyclones, capable of producing large hail and severe gusts.

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