Severe thunderstorms possible in southern France, northeastern Spain today June 27, 2017

A new long wave trough pushes into western Europe later today , bringing further destabilization of weather in the region. A round of severe thunderstorms is expected over southern France and possibly northeastern Spain.

500 mbar winds and height, GFS model guidance. Map: Pivotal Weather.

A strong 50-70 kt mid-level (500 mbar) jetstreak will move across the region. The surface airmass will be very warm and humid, with high resolution models indicating temperatures around 27-32 °C and dew points in 16-19 °C range across southern France. Moderate instability will build up, with MLCAPE generally 1000-2000 J/kg.

500 mbar winds and height, GFS model guidance. Map: Wetterzentrale.

Instability across the region, WRF model guidance. Map: Meteociel.fr.

Severe thunderstorms are expected across southern France as the left exit region of the jetstreak passes across the region in the afternoon. With up to about 40 kt deep-layer shear and locally fairly high SREH3 values around 200 m2/s2, organized thunderstorms, including supercells are expected. Main threats will include large, locally very large hail, severe wind gusts and torrential rainfall.

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