Storm Forecast
Valid: Sun 20 Nov 2011 06:00 to Mon 21 Nov 2011 06:00 UTC
Issued: Sat 19 Nov 2011 22:38
Forecaster: TUSCHY

A level 1was issued for far S-Portugal/Spain mainly for heavy rainfall amounts.

SYNOPSIS

The main story of the day will be a rapidly eastward moving upper low over SW-Europe. Attendant surface depression moves ashore along the NW-coast of Morocco and seems to reform further east over N-Algeria, where baroclinity increases.
Sporadic storms are possible over the Bay of Biscay as a weak upper trough moves in from the west during the night. Shear will be too weak for anything severe. For the rest of Europe, conditions remain stable regarding DMC chances.

DISCUSSION

... S-Portugal/Spain and W-Mediterranean ...

The thunderstorm activity remains confined to the eastward moving low. During the daytime hours, scattered showers/thunderstorms still affect far S-Portugal/Spain and offshore areas. Convective storms may repeatedly move ashore and hence an heavy rainfall risk exists. Coastal areas were included into a marginal level 1 as some low-end CAPE exists. The overall risk diminishes after sunset.

As the LL depression reforms over Algeria in conjunction to the eastward moving negative tilted upper low, an EML moves offshore over the W-Mediterranean. With maritime air mass beneath, modest CAPE build-up is expected...mainly capped along the coast of N-Africa. Further to the north, scattered thunderstorms evolve during the night hours. 6 km bulk shear increases from the coast of S-France (~ 5 m/s) to N-Africa (15-20 m/s), so pulsating storms/a few multicells are forecast. This may assist in an isolated large hail event over the Balearic Islands during the night. Overall risk is too sporadic for any level area. Nevertheless, atmospheric conditions successively become more favorabel for severe storms over the W-CNTRL Mediterranean after 00Z.