Storm Forecast
Valid: Thu 05 Jan 2017 06:00 to Fri 06 Jan 2017 06:00 UTC
Issued: Thu 05 Jan 2017 05:56
Forecaster: GATZEN

A level 1 was issued for western and southern Turkey, western/southern and north-eastern Greece, and western Albania mainly for excessive rain and to a lesser extend severe convective wind gusts.

SYNOPSIS

An arctic trough rapidly amplifies across eastern central Europe. Cold air spreads into the forecast region except for the far western portions. This air mass is very dry with a mixing ratio below 3 g/kg, limiting the potential of thunderstorms. However, some patches of better moisture can evolve over the warm waters of the Baltic and North Sea. Better moisture is also present across the Mediterranean, especially ahead of the cold front. Thunderstorms have already developed here.

DISCUSSION

East Mediterranean

Ahead of the amplifying long-wave trough, a strong south-westerly flow has evolved across the eastern part of the Mediterranean. Flow-parallel convergence lines and frontal boundaries have developed ahead of the cold front that currently moving across the central Adriatic. These bands of showers and thunderstorms have formed within a nearly saturated air mass with weak instability as indicated by latest Trapani and Izmir soundings. Although intense convective storms are not forecast given limited CAPE and also vertical wind shear, excessive rain is expected especially where topographic / onshore lift will support deep moist convection. Highest potential is forecast across the shores and coastal mountains of southern and western Turkey in the morning hours, but further excessive rain events can be expected over the Ionian and Aegean Sea region as well, with a focus on western Greece. Together with the rain threat, potential of severe convective wind gusts increases across the Aegean Sea region late in the forecast period given strong flow and increasing vertical wind shear.

In the wake of the cold front, very dry and cold air masses spread into the central Mediterranean. Some more thunderstorms can be expected over the Tyrrhenian Sea where moisture is not too weak. However, severe thunderstorms are not expected there as well given limited CAPE and low-level convergence.

As a side note, strong non-convective wind events are expected during the forecast period, especially a strong Bora event from the Dinaric mountains to the Adriatic Sea, but also a Mistral event over the west Mediterranean and a storm system affecting the Aegean region late in the forecast period. These storms are not caused by convective storms and are not addresses by the threat levels and text.