Storm Forecast
Valid: Sun 12 Sep 2010 06:00 to Mon 13 Sep 2010 06:00 UTC
Issued: Sun 12 Sep 2010 05:58
Forecaster: SCHLENCZEK
A level 1 was issued for W Turkey mainly for excessive precipitation and to a lesser extent for large hail and severe wind gusts.
SYNOPSIS / DISCUSSION
Remnants of an upper cut-off low over the E Mediterranean will move to the northeast, affecting W Turkey and the Bosporus region. Most convection should be associated with the frontal boundary which separates very hot and dry air over the Arabian Peninsula from moderately warm and moist air over the Mediterranean region. Recent GFS model outputs suggest that some hundred J/kg CAPE and 15 - 20 m/s deep layer shear should be in place. Current thinking is that one or two MCSes may develop with excessive rainfall being the main threat. Especially in the initial phase, storms may produce isolated large hail and a few severe wind gust events.
A second upper vort-max will cross parts of the S Adriatic during the afternoon. With some hundred J/kg CAPE and 10 - 15 m/s shear, a few organized multicells could form and an isolated heavy rain / large hail event is not ruled out. The possibility of waterspouts seems to be rather low but an isolated event may occur.
Some isolated convection may develop over the N Maghreb States and S Iberia where a plume of very warm air is present. Storms should stay isolated due to a strong capping inversion and absence of upper level features which may provide some forcing. Locally, an isolated hail / wind gust event is not discounted.
An upper trough over the North Sea will cross France, Benelux and W Germany during the day. In the vicinity of the cold front, some hundred J/kg of CAPE and 15 - 25 m/s deep layer shear should be available and some briefly organized multicells and / or a convective line may form. Apart from an isolated severe wind gust / marginally severe hail, most storms should stay sub-severe and a threat level is not warranted. Some isolated thunder may be observed over S Norway and parts of the North Sea as well.
