Storm Forecast
Valid: Sun 07 Dec 2008 06:00 to Mon 08 Dec 2008 06:00 UTC
Issued: Sat 06 Dec 2008 23:35
Forecaster: SCHLENCZEK
SYNOPSIS
A large upper trough over eastern Europe will shift eastward during the period. At its southern tip, a tongue of warm and moist air is advected into western Turkey where the left exit of a 35 m/s subtropical jet streak is present. In the wake of the trough, a cold polar airmass will overspread the Balkans. An upper cut off low over NW Iberia will lead to unsettled conditions in parts of Spain and Portugal.
In the vicinity of a strong 65 m/s upper jet streak, rapid cyclogenesis is forecast between Iceland and northern Scandinavia. The developing intense surface low will likely affect Iceland and northern Norway, leading to severe but mostly non-convective winds.
DISCUSSION
...NW Iberia...
As the upper low moves slowly southeastward, cold upper air will overspread the region, leading to some hundred J/kg of CAPE. Deep layer shear in order of 10 m/s may allow a few organized multicells which pose a threat of marginally severe hail and / or strong gusts. Intensity and coverage of severe weather will likely be too low for a threat level.
...Adriatic Sea, Balkans...
Weak instability is present in the wake of the large upper trough that covers most parts of eastern Europe. Even though 0-6 km deep layer shear is quite strong, a large area of differential anticyclonic vorticity advection will likely suppress convective initiation and storm coverage will be very limited. Isolated waterspouts over the Adriatic Sea are not ruled out but a threat level is not warranted.
...E Mediterranean, SW Turkey...
A tongue of warm and moist air over the eastern Mediterranean will be advected eastward into southwestern / southern Turkey during the day. Only a small region with an overlap of more than 10 m/s deep layer shear and CAPE will exist and additionally weak forcing will minimize the threat of severe weather. Marginally large hail, gusty winds and a brief tornado cannot be discounted but a threat level is not warranted. Storms will leave the forecast area during the afternoon and continue towards Syria.
