I saw a very impressive shelfcloud, with intense colours. It came nearby too fast. Somewhat threatening when you pass a large water (Hollands Diep) by bridge I drove along the gust front - lightning on my left side, dust, branches and leaves swirling on the highway A29 - to my home. During the night there was 'stroboscope lightning'. Also some supercells passed that night. In France there were tornadoes and in Germany and France several 'Funnel clouds'.
Estofex forecast:
" A level 2 was issued for N France and Benelux mainly for severe wind gusts, large hail, tornadoes and excessive precipitation.
....N France, Benelux....
Two waves of thunderstorms are simulated by models in this region.
The first one is expected with an isolated storm development in the afternoon hours. Impressive instability release is predicted with MLCAPEs probably reaching locally more than 3000 J/kg and in combination with moderate wind shear ( 15 m/s in 0-6 km layer), any developing thunderstorm will have a chance to produce large, or even giant hail. Delta Theta E values should reach more than 16 K, implying a threat of downbursts in the storms. A development of MCS is not ruled out as storms will progress to the north. The initiation of storms seems to be most likely over NW France along the warm front that is moving northward.
The second wave of storms will reach the region in night hours, probably in form of one or more well developed MCS. At the same time a surface low will undergo a deepening process and strenghtening wind speeds at lower levels. At 850 level, strong southerly flow is anticipated wind windspeeds over 20 m/s. Increasing low and mid level shear suggest a serious wind gust threat with those MCS, especially in case bow echoes form. Furthermore, tornadoes are possible given the strong low level wind shear, low LCLs and a possibility that some embedded rotating structures will develop within MCS ( this is supported by the strenghtening SREH in the vicinity of the surface low). Very strong low level convergence, humid airmass and high rainfall amounts simulated by both GFS and ECMWF models point to the threat of heavy convective rainfall with MCS. "
Convection popping up near the "Dordtsche Kil"
Near the A59: panorama of shelfcloud
