+++Severe thunderstorm threat today in SE UK, N France and BeNeLux+++
A significant severe weather setup is shaping up for SE UK, N France and BeNeLux this afternoon, with potential for severe thunderstorms with large to very large hail, severe winds and heavy rainfall. High instability will build up over the region, with SBCAPE values in the 2000-3000 J/kg range, locally even exceeding 4000 J/kg. A moderately strong mid level jet overspreads the region with 40-50 kt southwesterly winds at 500 mbar level. Southerly to southeasterly surface winds provide ample shear and helicity, as DLS reaches 30-50 kt and SREH3 generally 100-200 m2/s2; the environment is highly supportive for organized thunderstorms, including supercells. Expect storm initiation in late afternoon across N-NW France, with storms moving NE into NE France, BeNeLux and SE UK. Main threats with these storms are large to very large hail, severe winds and heavy rainfall. Some models indicate very strong low level shear and 0-1km helicity (>20 kt LLS, >150-250 m2/s2 SREH1!!) over Brittany, Normandy and Pas-de-Calais - should these models verify, there will be a very significant threat of tornadoes in this zone! We will be monitoring this situation and providing updates.
Maps: Meteociel.fr, Wetterzentrale.de