Storm Forecast
Valid: Thu 15 Jan 2009 06:00 to Fri 16 Jan 2009 06:00 UTC
Issued: Wed 14 Jan 2009 22:01
Forecaster: GATZEN

SYNOPSIS

Amplified troughs dominate the European sector. During the period, one if these is situated from Scandinavia to the central Mediterranean, while the trough axis tilts from Tunisia north-eastward into southern Greece. To the west, another sharp trough will enter Morocco and Portugal as well as the western British Isles and Iceland. Cold air masses have flooded most of Europe and northern Africa. A tongue of slightly warmer air mass will spread into the eastern Mediterranean ahead of the Tunisian trough axis.

DISCUSSION

Central and eastern Mediterranean

Deep cold air mass covers the Mediterranean Sea in the range of the trough axis, where temperatures in the 500 hPa level are below -25°C. Away from the dry northern coasts, low-level moisture will be in the range of 5-8 g/kg mixing ratio, and rather steep lapse rates will likely be associated with some instability. Best instability is expected in the southern portions, where low-level moisture is highest, although a weak capping inversion may for due to some warm air advection above the boundary. Given low-level convergence underneath the trough axis and additionally QG forcing in the southern portions, deep convection is forecast to form. Given relatively weak vertical wind shear over most of the region, a level one is not issued. Best potential for a few more organized convective cells exists near Turkey, where deep layer vertical wind shear will be quite strong in the range of the upper jet, but severe weather seems to be rather unlikely due to weak instability during the period.