Storm Forecast
Valid: Wed 06 Dec 2006 06:00 to Thu 07 Dec 2006 06:00 UTC
Issued: Tue 05 Dec 2006 17:12
Forecaster: GATZEN

SYNOPSIS

Low geopotential present over north-western Europe. A sharp and amplified short-wave trough moves into the delta-flow regime over south-western Europe where it starts to cut off. This leads to strong cyclogenesis over western Mediterranean. To the east, upper high remains over eastern Europe.

DISCUSSION

Western Mediterranean

Latest soundings indicate quite moist boundary layer over western Mediterranean and steep lapse rates in the mid-levels. On Wednesday, upper height falls due to approaching upper trough will likely yield some instability. Although low levels may be quite cold, amount of moistuire is expected to lead to surface-based instability. Showers and thunderstorms are expected to develop. Given rather unfavorable vertical wind shear east of approaching trough, severe thunderstorms are not forecast. Thunderstorms are expected to spread into Italy during the period, where intense precipitation may occur.

North Sea region

In the range of upper trough, convectively mixed air mass characterized by neutral to slightly unstable lapse rates is present and forecast to spread into North Sea region and southern Scandinavia. Showers that are weakly electrified are forecast. Given weak instability and unfavorable vertical wind shear over most places, rather weakly developed convection is forecast, and severe potential seems to be quite weak. An isolated severe wind gust is not ruled out though. Near the trough center, weak vertical wind shear is present, and a few waterspouts may form.