Storm Forecast
Valid: Tue 26 Mar 2013 06:00 to Wed 27 Mar 2013 06:00 UTC
Issued: Mon 25 Mar 2013 23:35
Forecaster: TUSCHY

SYNOPSIS

An exceptionally far south displaced frontal boundary remains anchored over S-Europe and runs from the Iberian Peninsula to the Aegean Sea. Embedded impulses result in temporarily and locally enhanced thunderstorm chances over the Mediterranean during the forecast period.

North of the frontal zone, cold and dry air suppresses any DMC.

DISCUSSION

... Aegean Sea and Greece ...

Yesterday's trough rapidly decays while moving slowly to the east. Nevertheless, cold mid-levels remain in place. With the surface low becoming quasi-stationary over N-Greece while decaying, enough BL moisture will still be found over the area of interest to support some thunderstorm activity.
Probably the most active area will be the W-coast of Turkey, where the best BL moisture will be found. Shear remains weak, so only an isolated waterspout risk accompanies that activity. During the night, the thunderstorms gradually dissolve. The storms over N-Greece will be mainly diurnal driven and non-severe with a rapid end around sunset.

Another round of storms occurs during the overnight hours along the NW coast of Greece and Albania as a diffluent mid-level trough approaches from the west. The tilt and structure of this trough, coupled with modest BL moisture raises concerns regarding DMC probabilities. This fear is supported by warm EL temperatures. Therefore the current thinking is that storms won't be able to convert 30 m/s DLS into mid-level rotation with a more likely result that weak updrafts will be torn apart. Therefore only a marginal hail and gusty wind risk is forecast with that activity.

... Portugal ...

Another impulse approaches Portugal after 12Z although it loses integrity during landfall. Despite a concentrated area of nice shear/CAPE overlap along the SW/W coast of Portugal, low-end DMC chances preclude the use of the "isolated tornado phrase" for now. However, marginal hail and gusty winds probably occur. The main risk likely occurs along the SW coast of Portugal, where MLCAPE approaches 500 J/kg. The most likely outcome of this event will be a transient flare up of isolated thunderstorms over SW Portugal during the afternoon with a rapid decay thereafter.