Storm Forecast
Valid: Thu 11 Feb 2010 06:00 to Fri 12 Feb 2010 06:00 UTC
Issued: Wed 10 Feb 2010 20:41
Forecaster: GATZEN

A level 1 was issued for western Turkey mainly for excessive rain.

A level 1 was issued for portions of the west Mediterranean Sea mainly for severe wind gusts.

SYNOPSIS

East of a high over the northern Atlantic, an intense arctic trough spreads into the west Mediterranean Sea. At its eastern flank, another intense short-wave trough propagates northward and crosses the Aegean and Black Sea region. It will provide strong forcing especially along the cold front occlusion spreading into Turkey early in the period. While steep lapse rates across the western Mediterranean and rather rich moisture over the eastern Mediterranean will be associated with some instability, potential of convection is quite weak to the north of the Mediterranean Sea.

DISCUSSION

Aegean Sea region to southern Black Sea region

The cold front occlusion of a low pressure system centred over the Adriatic Sea will spread across Turkey and the southern Black Sea region. In the range of this occlusion, a strong low-level jet advects moist and rather warm air masses northward into the southern Black Sea. The low-level mixing ratio is forecast to reach about 6 g/kg. Given the strong QG forcing as well as orographic lift along the Turkish coasts, excessive precipitation is forecast especially over western Turkey. Although the precipitation will be of stratiform nature, latest models indicate that weak CAPE will be present in the range of the warm air axis. Given rather steep mid-level lapse rates in the range of the trough axis, deep moist convection may be embedded along the occlusion, and some lightning is also possible. Later in the period, the trough axis is forecast to spread northward, and cold air advection will likely limit the potential of severe convection.

West Mediterranean Sea

A strong Mistral will go on on Thursday across the west Mediterranean. Given the very cold air spreading across the sea, rather deep mixing will be possible, and shallow convection is likely to develop especially from the central and southern portions, spreading eastward into Italy later on. The potential of severe wind gusts in the range of these showers is rather high given the strong winds at low levels. Marginally large hail may be possible along the coast of Algeria and Tunisia, where instability will be strongest. Additionally, waterspout may occur during the period.