Forecast Update
Valid: Wed 10 Jan 2007 17:00 to Thu 11 Jan 2007 06:00 UTC
Issued: Wed 10 Jan 2007 17:25
Forecaster: GATZEN

SYNOPSIS

Propagating cold front now over north-western Germany, Belgium, and northern France continues its way south-eastward. Latest Herstmonceux sounding indicates that significant instability has developed in the range of complex frontal boundary over western Europe. While low-level moisture has increased reaching dewpoints of nearly 10°C in a narrow corridor just ahead of approaching surface cold front, mid-level temperature has decreased behind a kind of split-front that has entered the warm sector - or at least it seems to be something like that looking at latest soundings from De Bilt, Herstmonceux, and Nottingham. Along the cold front, latest radar observations indicate a strongly-forced convective line that has intensified over Benelux, producing embedded thunderstorms. Given moderate to strong south-westerly surface winds, very strong low-level vertical wind shear and favorable veering with high low-level helicity, combined with almost no CIN and significant CAPE at low levels can be expected, and tornadoes along the leading edge of the convective line are forecast to occur. A strong tornado is not ruled out. Severe wind gusts will pose another significant severe threat. Convective activity is expected to spread into northern Germany where isolated thunderstorms are also not ruled out. Chance for tornadoes is forecast to decrease as low-level moisture will be lower further inland. However, given rather favorable set-up, chance seems to be big enough to warrant a level 1, though.