Storm Forecast
Valid: Wed 21 Nov 2007 06:00 to Thu 22 Nov 2007 06:00 UTC
Issued: Tue 20 Nov 2007 14:07
Forecaster: GATZEN

SYNOPSIS / DISCUSSION

Large high covers east Europe during the period, filled with rather dry and stable air mass. To the west, an amplified weakening trough will remain over west Europe. Warm air advection is present between both features over west Mediterranean and Germany.

The warm air mass is characterized by steep mid-level lapse rates and strong capping inversion as indicated by latest Palma De Mallorca sounding, and it is not expected that this capping will weaken significantly at first. Late in the period, approaching cold front will lead to low-level forcing, and it is not ruled out that the cap will break. Convection may be accompanied by thunder over southern France and west Mediterranean, but strong convection is not expected at this time. Near southern Franc, models suggest strong low-level convergence, but given limited low-level buoyancy and only moderate vertical wind shear, severe convection is forecast to be rather unlikely.

In the range of the trough center, cold mid-level air mass has become unstable over the warm sea surface, and thunderstorms will likely go on. With weak vertical wind shear and rather nice low-level buoyancy, waterspouts are forecast to develop. Best potential seem to exist along the west coast of the Iberian Peninsula in the morning hours on Thursday.