Storm Forecast
Valid: Thu 03 Jan 2008 06:00 to Fri 04 Jan 2008 06:00 UTC
Issued: Thu 03 Jan 2008 05:31
Forecaster: GATZEN

SYNOPSIS / DISCUSSION

Large high over east Europe remains during the period. Cold and dry air mass is present over most of the forecast area. A trough over south-west Europe evades into northern Africa. In the range of this trough, steep low-level lapse rates and almost some boundary-layer moisture is present as indicated by latest ascends.

During the day, a strong upper jet streak is forecast to spread northward at the eastern flank of the upper trough, providing strong QG forcing over Spain, and extremely west Mediterranean. At lower levels, a weak cold front propagates eastward over Iberian Peninsula. Along this cold front, forcing is forecast to be sufficient for showers and thunderstorms to develop. A convective line is expected that will move eastward slowly. Given strong vertical wind shear in the range of the jet streak, some convective downdrafts may produce severe wind gusts.

Over the Atlantic west of the Iberian Peninsula, showers and thunderstorms are forecast in the range of the trough. Waterspouts are not ruled out given rather strong low-level buoyancy and weak vertical wind shear.

Over northern Morocco, chance for severe convection will stringly increase during the period. Low-level moisture has increased as indicated by latest observations. As a very strong northerly jet evades into western Morocco, strong QG forcing is forecast, and showers and thunderstorms seem to be quite likely. Given very strong vertical wind shear, supercells may develop initially, capable of producing large hail and severe wind gusts. Later, convection may organize into one or two MCS moving eastward. Severe wind gusts will be the main threat late in the day.