Storm Forecast Valid: Tue 30 Sep 2014 06:00 to Wed 01 Oct 2014 06:00 UTC Issued: Mon 29 Sep 2014 22:00 Forecaster: GATZEN
A level 2 was issued for parts of the west Mediterranean mainly for excessive precipitation and to a lower extend large hail and tornadoes.
A level 1 was issued for most of the west Mediterranean region mainly for excessive precipitation.
The south-west-European trough is weakening. Its northern portions will move eastwards into central Europe, pushing the ridge south-east. At low levels, the moist air mass over France spreads eastward, before cold air advection sets in from the north late in the period. Across the west Mediterranean, the very moist easterly low-level flow will continue, but unfavourable large-scale forcing will limit severe potential.
On Tuesday, convective activity with the potential of excessive rain will go on along the eastern portions of Spain, the southern portions of France, and the west Mediterranean Sea. Upslope flow and frontogenetical forcing are still present. During the second half of the day, weaker QG forcing in the wake of the eastward moving short-wave trough can limit the potential of excessive rain. Given weak vertical wind shear, chance of hail and tornadoes is expected to be rather low.
Strong vertical wind shear is expected across the south-western Mediterranean area including south-eastern Spain and the Balearic Islands due to north-easterly surface winds and south-westerly flow at mid levels. A few well-organized storms are forecast along the sea-breeze convergence over Spain and near the frontal boundary over the Mediterranean Sea. These storms may be capable of producing large hail and tornadoes.