...... Any other details re wind speeds or shear at the time?
when the phenomenon occurred, the surface winds were like this:
The shower was located over the center of Vienna, the city weather station reported gusts of 61 km/h during the shower, whereas at the location where i took the footage (3km east of of the weather station) there where very low windspeeds, as you can see looking at the tree.
the sounding shows a typical spring cold air situation with a little bit of cape and a considerable windshear, as you can see from the profile, so scattered showers were likely to occur.
looking at the synoptic situation you can see that there is a jet on the backside of a pronounced trough located over Austria.
looking at the charts and figures it`s not too surprising that there was a little bit of rotation, overall the available energy was very low and therefore no severe convection occurred. on the other hand, similar cold air situations are responsible for most of the (not too violent) tornadoes in middle and western Europe, when cape and shear are considerably higher, i.e the trough is more pronounced and the cold air mass is more unstable. several tornadoes were reported in germany on mar. 27th 2006
.. which shows the same pattern .. a cyclonic situation, cold air behind a cold front and a strong jet
regards
Manfred
