Storm Forecast
Valid: Sun 16 Dec 2012 06:00 to Mon 17 Dec 2012 06:00 UTC
Issued: Sun 16 Dec 2012 05:34
Forecaster: VAN DER VELDE

A level 1 was issued for western France mainly for a tornado chance and marginally severe convective wind gusts.

SYNOPSIS

A very large depression with its center NW of Ireland covers much of the western half of Europe. With a strong westerly flow unstable airmass is transported onto the shores of the British Isles and France. At the time of writing only convection south of about 48°N is electrically active and occurs under the jet stream. The airmass is not so cold to have a lack of moisture content, in fact with 6-8 g/kg there is ample fuel for electrified cells. This will continue into most of the day with a wave reaching France around noon, probably with enhanced convective activity during the afternoon. Wind profiles will have 15-25 m/s 0-6 km shear, and over land more than 10 m/s 0-1 km shear. This may induce some low-topped mini supercells or shortlived mesocyclones which could produce a tornado. Low level flow decreases and convective wind gusts over 25 m/s are becoming less likely.