Storm Forecast
Valid: Thu 09 Dec 2010 06:00 to Fri 10 Dec 2010 06:00 UTC
Issued: Wed 08 Dec 2010 21:58
Forecaster: GATZEN
A level 1 was issued for western Turkey mainly for tornadoes.
SYNOPSIS
To the east of high geopotential over the northern Atlantic, the European long-wave trough rapidly amplifies on Thursday. Two vort-maxima will move south-eastwards across central Europe and cold air advects into the Balkans and western Black Sea region late in the period. To the south-west, the low geopotential will cut off to the west of the Iberian Peninsula.
DISCUSSION
Iberia
Rising geopotential is forecast given warm air advection and strong DAVA. The large-scale sinking will result in increasing capping of the moist low-level air masses. Together with weak low-level forcing, the chances of initiation will decrease on Thursday. The best potential of some storms exist over the western parts in the morning hours that will be influenced by warm air advection, but instability will be marginal over these regions. Overall threat of organized convection is expected to be very low although strong vertical wind shear and favourably veering profiles are forecast with 25 m/s bulk shear and 300 mē/sē SRH in the lowest 3 km. Later in the period, chance of storms will gradually decrease from the south.
Adriatic Sea to Aegean Sea
Ahead of the amplifying long-wave trough, the mid-level flow is forecast to intensify over the central Mediterranean. The associated lift at the cyclonic flank of an approaching jet streak will increase the lapse rates and CAPE is expected to develop given a moist boundary-layer over the sea surface. Especially along the surface cold front, low-level forcing is expected to be sufficient for initiation. Additional storms are forecast at the western coasts of the Balkans and the Turkey region given the upslope south-westerly flow.
Current thinking is that showers and embedded thunderstorms will develop along the cold front over the Adriatic and western Balkans that will spread southward during the period. The vertical wind shear seems to be not too supportive for organized storms although 20 m/s deep layer bulk shear is expected. Farther south, some showers and thunderstorms may also develop during the day over Greece and the Aegean Sea. Low-level veering and buoyancy is expected to increase during the period and some storms may be capable of producing a tornado given strong low-level vertical wind shear. The best potential is forecast along the western coasts of Turkey.
