Forecast Update
Valid: Mon 01 Feb 2010 20:00 to Tue 02 Feb 2010 06:00 UTC
Issued: Mon 01 Feb 2010 20:38
Forecaster: TUSCHY

A level 1 was issued for S Greece mainly for isolated severe wind gusts, an isolated tornado and locally high rain amounts.

A level 1 was issued for the Aegean Sea and NW/W-Turkey mainly for large hail, severe wind gusts, excessive rainfall and an isolated tornado.

SYNOPSIS

Please refer to the main outlook, issued at Sun 31 Jan 2010 21:18 UTC.

DISCUSSION

... Aegean Sea and W-Turkey ...

This update was issued to convey the final decision not to upgrade parts of the level 1 to a level 2, which was contemplated in the main outlook.

Latest synop maps show a quasi-stationary boundary over NW-Turkey down to the central Aegean Sea, becoming more diffuse over the rough terrain of S-Greece. Weak mid-level PVA currently affects NW-Turkey which helped to activate the surface boundary over the far NE Aegean Sea. Repeated showers/thunderstorms evolve along this front and trail towards the NE with good moisture input from the south. This activity probably keeps going during the night, as further lift approaches from the SW.

Last WV image prints a developing upper wave over Sicily/south Italy with a cooling and expanding cloud shield now entering the central/eastern Ionian Sea. This wave likely helps scattered showers/thunderstorms to develop over S-Greece until midnight with an isolated tornado/severe wind gust risk.

More robust development is anticipated over the Aegean Sea after midnight, as the upper wave moves atop the surface baroclinic zone. Broad surface pressure fall is forecast, but not as intense, as was seen in earlier model data. The main concern still is the triple point area somewhere over NW/W-Turkey (coastal area), as strengthening shear and modest CAPE overlap. In fact, Izmir, 12 UTC already looks suspicious for deep and organized convection and this environment will be present during the night. However, weakly capped conditions and stout forcing moving in from the west likely cause scattered to widespread showers/thunderstorms, which limits organization considerably. A few organized storms are still expected mainly along the coast of NW-/W-Turkey with large hail, severe wind gusts and an isolated tornado event. The main risk will be strong rainfall, as the surface front needs some time before accelerating towards the southeast. Excessive rainfall/icing/snowfall is still anticipated along the occlusion over NW-Turkey. A level 1 may cover the risk as mixed precipitation ingredients may keep overall flooding risk more isolated in nature. In addition, the strongest rain shield evolves just at the end of the forecast period.

Thunderstorm risk over the Adriatic/Tyrrhenian Sea is conditional, but latest satellite data show increasing convection over the northern part of the thunderstorm area with first lightning reported.