To add to the link Phil suggested above, here is a excerpt with the link:
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Hi Harald,
These are captures from the video sequence with some basic descriptions.
http://www.stormchasers.au.com/20_12_07.htm I had a look at the public available radar and noticed the significant storm appearing north of Cressy which appears to show a large hook echo of sorts, and then I suspect a propagating boundary moved northeast to generate the QLCS as suggested by you. It was interesting your mention of decoupled vorticity - could this explain the 2 funnels along the line prior to the 'main event'?
The sequence shows what I initially missed at the start - behind the lowering which I dismissed as scud, closer examination shows what appears to be a ground connection of vorticity. The tornado developed very rapidly to the point where I was overwhelmed by how quickly things went from that point. Interestingly the 2 funnels didn't appear to move very much, but the tornado, after developing, moved to the ENE quite rapidly. In the final sequences, rain appears to wrap around the vorticity centre which now develops into a large bell shape with a collar.
I hope these images will be of use in your research in atmospheric oddities, and I would be very happy at some stage to go over the video and get a deeper understanding of the processes particularly with your radar analysis and experience in severe weather.
best regards.....Clyve Herbert
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Phil, given you saw these video stills, what are your thoughts from what you see?
Regards,
Jimmy Deguara