Storm Forecast
Valid: Sun 14 Dec 2008 06:00 to Mon 15 Dec 2008 06:00 UTC
Issued: Sun 14 Dec 2008 00:05
Forecaster: SCHLENCZEK
SYNOPSIS
A large upper trough over the East Atlantic extends southward into the western Mediterranean. At its rear flank, an impressive 90 m/s upper jet streak points from Iceland to southern Portugal. Stable conditions under a large upper high will continue over eastern Europe. Otherwise, a severe precipitation event is expected for parts of southern France and NW Italy ahead of a developing low pressure system.
DISCUSSION
...Bay of Biscay, N Iberia...
Some hundred J/kg of CAPE are present over the Bay of Biscay in the wake of the upper trough. Showers and thunderstorms with sporadic lightning will develop during the day but weak forcing and marginal shear will limit the threat of severe weather.
...SW Mediterranean...
Ahead of the upper trough, a region with marginal CAPE will be affected by an upper vort max in the afternoon. Forcing will likely be sufficient for ascent and 20 m/s deep layer shear may allow a few organized multicells that could be accompanied by marginally severe gusts. Although LL shear is weak, an isolated funnel / brief tornado cannot be discounted given a moist BL and LL lapse rates around 10 K/km.
...S France, Gulf of Genua, Corsica...
On Sunday morning, a few hundred J/kg of CAPE are present in the region and some thunderstorms may develop. Storms will likely merge into one or two large systems with rather sporadic lightning but those systems may produce torrential rainfall with possible flash floods.
...S Adriatic Sea, Greece...
An upper shortwave trough will move across Sicily and the southern Adriatic Sea during the afternoon. Ahead of the trough, a few hundred J/kg of CAPE will be created and thunderstorms will develop in an environment with some QG forcing and about 15 m/s deep layer shear. Severe weather should be unlikely as CAPE is low and the layer with positive CAPE is rather shallow.
Similar conditions but weaker forcing are expected for the Aegean Sea and western Turkey. Some thunderstorms are possible but severe weather is unlikely.
