hi,
indeed , there was a lot of activity that day, despite the fact that's quite late for severe thunderstorms to develop in central Europe, as the season is coming to an end.
radar imagery is a little bit ambiguous, you don`t get to see to many supercell features.
over the judenburg district you see some interesting features
changing into a pronounced bow shape over the koeflach district
and after that more and more into a line shape and a mesoscale complex
#
here is an animation (17MB), source= Austrocontrol
http://www.phix.cc/gew_09.htmlespecially towards the end of the animation (southern Styria), when you took your pictures, i can`t see clear features of a supercell, in this case it`s mainly up to you to decide.
regards
Manfred