Commentary: There was a deep, dry blue sky combined with anticyclonic subsidence over northern Switzerland, but the very strong midday sun and upslope northerly (and orographic) flow set off a brief but powerful single cell over the Diablerets region of the Vaudois / Walliser Alps between 16 and 20h. In this animation, notice the delicate balance between the rapidly-evaporating cumulus towers and the newly ascending ones - try viewing the movie in reverse (by pressing the "Swp" button), it looks almost the same! The speed of evaporation and sinking motion of the old towers completely surprised me - the air must have been very dry and stable. Notice also that the anvil is icing over and elongating more in the later images.
Comments to eddyjune(at)bluewin.ch