Storm Forecast

Storm Forecast
Valid: Tue 22 Oct 2019 06:00 to Wed 23 Oct 2019 06:00 UTC
Issued: Mon 21 Oct 2019 19:16
Forecaster: DAFIS

A level 2 was issued for Spain, France, and Algeria for excessive precipitation, severe wind gusts, large hail, and tornadoes.

A level 1 was issued for Cyprus and Turkey mainly for large hail and severe wind gusts.

SYNOPSIS

A wide-positively tilted trough in western Europe with an intensifying hook-shaped PVA over the Iberian Peninsula, creates a strong bariclinic zone in West Mediterranean. A dangerous set-up is about to take place in the eastern parts of the Iberia and southern France on Tuesday 22 and Wednesday 23/10.
Another vorticity max can be found at the eastern parts of the omega-blocking pattern, over Turkey and Cyprus. Unstable air masses result in local severe weather.
The largest part of the continent will be under the influence of an anticyclone with strong subsidence, unseasonably high temperatures, and foggy conditions.

DISCUSSION

.... Spain, France, and Algeria ....

On Tuesday 22/10 a cyclonic Rossby-wave breaking will take place in western Europe, where a cold air mass has reached the NW parts of Africa. A strong southerly flow has been established in West Mediterranean where the advection of warm and moist air masses on the coasts of Spain and France will result in high-precipitating events. Locally, more than 200 mm of accumulated precipitation is expected, in less than 24-hours.
A jet of 30 m/s at 850 hPa creates strong low-level shear, overlapping with high CAPE and SREH. Supercells are expected, able to create large hail and tornadoes. Tornadic waterspouts close to the coasts may pose a serious threat.
In Algeria, the main threat will be large hail and severe wind gusts, where a convergence zone in the morning and early afternoon will organize storms in clusters with training convection in the northern parts of the country. Convection should stay offshore during the night.

.... Cyprus and Turkey ....

Under a cut-off low, air masses with high theta-e values and steep mid-level lapse rates create high values of NCAPE with 1500-2000 J/kg MLCAPE near the coasts. Storms are expected within the strongest vorticity maxima and low-level convergence zones (local breezes/orography), able to produce large hail and severe wind gusts. In Turkey, most of the storms will be driven by diurnal heat. The convective activity should be weak during the night.

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