Storm Forecast
Valid: Thu 16 Dec 2010 06:00 to Fri 17 Dec 2010 06:00 UTC
Issued: Wed 15 Dec 2010 22:47
Forecaster: GATZEN

A level 1 was issued for parts of Greece and Turkey mainly for excessive rain.

SYNOPSIS

The European long-wave trough re-intensifies as an arctic trough spreads southward into the North Sea. A south-westerly mid-level jet stream will affect the south-eastern parts. Except of the Aegean and Turkey, cold air masses dominate Europe. Late in the period, some warm air will spread across Iberia into the west Mediterranean ahead of the arctic trough.

DISCUSSION

Aegean and Turkey

A cold front is situated from southern Greece to the Aegean Sea and western Turkey and will accelerate eastward during the forecast period. A moist low-low-level air mass is present ahead of this cold front and latest soundings indicate weak instability that is also expected on Thursday when the mid-level trough expands eastward leading to some QG forcing. Along and east of the cold front, thunderstorms are forecast. Given the weak instability, large hail is not forecast. Additionally, severe wind gusts seem to be not very likely given only moderate low-level winds. However, some organized storms are forecast to evolve given about 10 m/s bulk shear in the lowest 3 km. An isolated tornado is not ruled out especially near the coasts where the 0-1km vertical wind shear is expected to exceed 8 m/s. The most significant threat will be excessive rain along the south-western coasts, where numerous thunderstorms can cause high 24 h accumulated precipitation.