Zelf verwacht ik de grootste kans op onweersbuien ook in het uiterste zuiden van België en Luxemburg. Noorderlijker lijkt de atmosfeer te stabiel en te droog voor significante buienvorming. De invloed van hogedruk zal daar ook het meeste merkbaar zijn.
...France, extremely northern Iberian Peninsula, Benelux, western Germany ...
Very unstable airmass is expected due to latest soundings. Steep lapse rates present over northern Iberian Peninsula and southern France should spread northward. Underneath the cap that is expected at the 850 hPa level ... low-level moisture should increase significantly during the next hours, and CAPE should likely reach up to 2000 J/kg during the day. In the afternoon ... surface low/convergence line is expected over central France due to insolation ... and low-level convergence, orographically enhanced UVM and strong insolation should lead to initiation. Initially weak vertical wind shear is forecast. However ... high CAPE values may be sufficient for supercells, though. Very large hail and damaging wind gusts will be likely with any supercell that forms. Thunderstorms are expected to cluster later on. In the evening ... upper jet streak is forecast over northern France ... and deep vertical wind shear/upward forcing will increase gradually. Due to decreasing LCL heights ... tornado threat seems to increase from central France to Benelux. A few tornadoes are expected. Thunderstorms may organize into a MCS that should move NE-ward reaching Benelux and western Germany later on. Severe wind gusts should be the main severe threat during the night hours.
...France, extremely northern Iberian Peninsula, Benelux, western Germany ...
Very unstable airmass is expected due to latest soundings. Steep lapse rates present over northern Iberian Peninsula and southern France should spread northward. Underneath the cap that is expected at the 850 hPa level ... low-level moisture should increase significantly during the next hours, and CAPE should likely reach up to 2000 J/kg during the day. In the afternoon ... surface low/convergence line is expected over central France due to insolation ... and low-level convergence, orographically enhanced UVM and strong insolation should lead to initiation. Initially weak vertical wind shear is forecast. However ... high CAPE values may be sufficient for supercells, though. Very large hail and damaging wind gusts will be likely with any supercell that forms. Thunderstorms are expected to cluster later on. In the evening ... upper jet streak is forecast over northern France ... and deep vertical wind shear/upward forcing will increase gradually. Due to decreasing LCL heights ... tornado threat seems to increase from central France to Benelux. A few tornadoes are expected. Thunderstorms may organize into a MCS that should move NE-ward reaching Benelux and western Germany later on. Severe wind gusts should be the main severe threat during the night hours.
