Storm Forecast
Valid: Tue 30 Aug 2011 06:00 to Wed 31 Aug 2011 06:00 UTC
Issued: Mon 29 Aug 2011 21:54
Forecaster: KOROSEC

A level 1 was issued for parts of eastern Iberia mainly for large hail and severe winds.

A level 1 was issued for NW Russia mainly for tornadoes and severe winds.

A level 1 was issued for northern Algeria and Tunisia mainly for large hail and severe winds.

SYNOPSIS

A large upper trough still rotates over Scandinavia. On its eastern flank, a short-wave translates across NW Russia. NW of Iberia, an upper low become more defined while moving towards east. WAA spreading across the Mediterranean with the SW flow.

DISCUSSION

... parts of eastern Iberia ...

South-easterly LL flow from the western Mediterranean will again support advection of warm/humid airmass inland into eastern Spain. This should result in moderately strong instability, combined with moderate deep layer shear/SREH supportive of organized convection. A couple of intense multicells and a few supercells will be possible. Given the high LCL heights and steep lapse rates, large hail and severe wind gusts seem likely with the most intense cells.

... NW Russia ...

A short-wave trough with frontal system rapidly translates across the level 1 area. Several hundreds of MLCAPE overlaps with 25 m/s of deep layer shear and around 10 m/s of LL shear. Combined with around 200 m^2/s^2 of SREH, conditions will become favorable for well organized severe storms, including supercells. Those will be capable of producing tornadoes and severe wind gusts.

... northern Algeria and Tunisia ...

Its likely that a few isolated storms will take place in the peak heating hours when rather strong instability results from a moist airmass advection onshore from the SW Mediterranean sea. With around 20 m/s deep layer shear, organized storms should initiate along the convergence line, bringing large hail and severe wind gusts threat.

Elswhere over the highlighted lightning areas, mainly daytime driven convective storms are expected, but in almost non-sheared envirnoment. So severe storms are unlikely. A couple of waterspouts could still be possible over parts of North and Baltic sea where steep LL lapse rates and weak wind field remains in place.