"A level 1 was issued for parts of NE-France, Belgium, the Netherlands and parts of NW-Germany mainly for excessive rainfall, isolated large hail and a low-end tornado risk."
"... Belgium, the Netherlands, NW-Germany and parts of NE-France....
During the night hours, a warm front continues to lift to the north, placing those areas in a very moist warm sector. Models agree well in a persistent convergent wind field as warm front stalls somewhere along the coast or just offshore. Postfrontal air mass gets characterized by deep and moist profiles with 925 hPa dewpoints in the mid tens, elongated moisture transport vectors/enhanced moisture flux, PWAT at or above 35 mm and nearly non-existent storm motion vectors. In addition, a modest right entrance jet at 300 hPa keeps SR-anvil layer wind field enhanced. Bound to neutral lapse rates profiles, about 1 kJ/kg MLCAPE seems reasonable... immediately along the convergence zone, even higher values are possible.
Scattered thunderstorms evolve during the day in a weakly capped environment and move in general towards the NW or N. Storms tend to reveal marginal net-movement over NE-France, Belgium and the Netherlands but could become more progressive over NW-Germany, as shear increases somewhat. Also, some weak directional shear is forecast, which may even assist in some updraft rotation/better organized thunderstorms. Regarding the threat, large hail and strong downdraft winds are well possible during the initiation stage, transforming more into a strong to isolated severe wind gust risk, as thunderstorms cluster/temporarily cold pool organization occurs. However, the main hazard will be excessive rain. During the night, thunderstorm activity onshore gradually decays but keeps going offshore, as large thunderstorm clusters persist.
Just as a side-note: Augmented LL-CAPE is forecast with low LCL-environment. Can't completely rule out an isolated funnel/tornado event, especially if outflow boundaries locally modify PBL wind field."
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