Mesoscale Discussion
Valid: Sun 10 Aug 2014 13:00 to Sun 10 Aug 2014 17:00 UTC
Issued: Sun 10 Aug 2014 13:27
Forecaster: GROENEMEIJER/PUCIK

At 13 UTC, a surface cold front associated with a cloud band eas located over NW France along a line from Dunkirk to le Mans to La Rochelle. Another line of clouds and a few storms was located further east from near Luxembourg to Limoges.

Ahead of the front, over NW France, very stronglow-level winds are evident per 12 UTC Trappes sounding and radar VAD with 25 m/s wind reported at 1500 m, yielding very strong low-level shear. Clearing skies ahead of the front should yield some further destabilization, which is also aided by lift ahead of the upper-level trough. With high 18-21 C dew point temperatures on the order of 1000-1500 J/kg CAPE should be able to form ahead of the front, and slightly higher values over eastern France.

Widespread storm development along the front and along the eastern line are expected during the coming hours. Given the strong shear, the storms will include supercells with strong low-level mesocyclones. A tornado threat will therefore exist with these storms. These tornadoes may be strong.

Additionally, severe winds will be an important risk and some large hail may occur as well. Until 17 UTC, the storms will move northeastward and affect Belgium the southern Netherlands, Luxembourg, parts of E France and W Germany and W Switzerland.