Storm Forecast
Valid: Sat 27 Sep 2014 06:00 to Sun 28 Sep 2014 06:00 UTC
Issued: Fri 26 Sep 2014 21:14
Forecaster: TUSCHY

A level 2 was issued for NW Turkey mainly for excessive rain.

A level 1 was issued for Turkey, the Aegean Sea and the E-Mediterranean mainly for excessive rain, isolated large hail and a few spout-type tornado events.

A level 1 was issued for the SW Mediterranean mainly for excessive rain and large hail.

A level 1 was issued for NW Portugal mainly for an isolated large hail event.

SYNOPSIS

Big high arches upward over S/CNTRL Europe. Flanking troughs bring thunderstorms to the Iberian Peninsula, the Aegean Sea and Turkey. Active cold sector convection occurs over Estonia and east of Finland.

DISCUSSION

... Turkey, Aegean Sea ...

Cyclone over Turkey deepens a bit during the forecast. Deepening phase levels off during the night. LL parcels experience longest possible fetch over the Black Sea (SSTs of 20-23 °C) before entering NW Turkey. Augmented upper divergence over plume of effective PWs in excess of 30 mm support excessive rain with SW-ward moving clusters. Two QPF maxima exist: One over NW Turkey, where training could result in rainfall amounts in excess of 100 mm/24 h. Another maximum could evolve along the E-coast of Greece with slow moving clusters. An isolated large hail event is possible. Augmented LLCAPE over the Aegean Sea should add a waterspout risk next to heavy rain.

... Strait of Gibraltar and Portugal...

Quasi-stationary warm front is focus for BL moisture pile-up over the Alboran Sea. Overlap of 1 kJ/kg MLCAPE and 20 m/s DLS exists all day long. Despite weak short-waves, no distinct forcing is seen, so CI occurs mainly due to mesoscale forcing (e.g. outflow boundaries) or with offshore moving storms from N-Morocco and NW Algeria. Large hail and severe wind gusts will be the main risk although excessive rain could become another risk for far SE Spain, if storms move ashore (PWs of 35-40 mm).

An upper low is placed NW of Portugal. Onshore flow advects marine layer well inland beneath cooler mid-levels. 500-800 J/kg MLCAPE and 10-15 m/s DLS result in a few better organized multicells with large hail the main risk. An isolated waterspout event is possible along the coasts of Portugal. We issued a broad 15-% lightning area for elevated convection during the night. Meager CAPE and weak shear preclude organized convection.

... Estonia to the NE ...

Active postfrontal convection occurs from noon to the late afternoon. Graupel and gusty winds remain the main risk.