Storm Forecast Valid: Mon 02 Mar 2015 06:00 to Tue 03 Mar 2015 06:00 UTC Issued: Mon 02 Mar 2015 05:01 Forecaster: VAN DER VELDE
A level 1 was issued for parts of UK, Belgium, Netherlands, Germany, Czech Republic, Austria, Slovakia and Poland mainly for severe convective wind gusts and tornadoes.
SYNOPSIS / DISCUSSION
A cold unstable airmass is driven into western and central Europe by a large low over the Norwegian Sea. The cold front lies over Poland to the Alps around 12Z. A sharp shortwave trough followed by drier and colder air passes over the southern UK into the European mainland, where a few hundred J/kg CAPE builds up during the afternoon ahead of the front. The trough likely triggers a wintry squall line moving at 80-100 km/h given the mean flow aloft. This will translate in similar speed wind gusts in convective downdrafts. The convective line may produce widespread gusts over 25 m/s, exceeding the level 2 criterion of 15% chance within 40 km from a point. Tornadoes are also possible with 10-15 m/s low level shear and a 0-6 km shear over 30 m/s. SREH of almost 200 m²/s² was predicted with this feature in the Keraunos WRF model of 18Z. The low/ mid level flow is weaker along the northern portion of the line which may limit the threat over northern Germany and Poland. The line may survive the night as it is driven by strong dynamics and reach Slovakia and surroundings.