The case from 09 June 2004 is an example of an unusual development of a super cell because it developed over the relative cool water of the North Sea and a second phase of intensifying occurred about 4 hours after sunrise over Northern Germany. Precipitation amounts up to 20 mm and gusts up to Beaufort 10 were registered.
An intense frontal zone extended from England to Eastern Europe. The Southern parts of the North Sea and Northern Germany were affected by its warmer edge. Near the passage of the super cell the radio soundings exhibited a strong vertical wind shear, potential instability between 1 and 5 km height and a tropopause at about 12 km with -64C.
The warm front was super-imposed by warm air advection and positive vorticity advection at the right entrance of a jet streak. That induced the development of a warm front wave. Within the potential unstable air during the evening of the 8th June a super cell developed near Scotland and moved after a temporary decaying and splitting till the morning of the 9th June to Hamburg. The right cell reached its maximum intensity at around 07 UTC.
Filed under Keywords:
Supercell, Mesoscale Convective System, Wave, Convection