May.25, 1999 - cloud lowering
 

May 25, 1999 - 3pm I was watching the dark clouds roll by and noticed an area that began to lower. I couldn't quite tell what it was as it only lasted about 5 minutes. Here are some vidcaps showing it lower, expand into what almost looks like a non-rotating wall cloud, then retract and dissipate:
http://www.ontariostorms.com/1999/may/25/may25-01.jpg Visible bands in the tower as it rises straight up.
http://www.ontariostorms.com/1999/may/25/may25-02.jpg Cloud lowering appears.
http://www.ontariostorms.com/1999/may/25/may25-03.jpg Zoomed in on lowering.
http://www.ontariostorms.com/1999/may/25/may25-04.jpg Formation continues to lower...
http://www.ontariostorms.com/1999/may/25/may25-05.jpg Formation spreads out at bottom.
http://www.ontariostorms.com/1999/may/25/may25-06.jpg A few seconds later.
http://www.ontariostorms.com/1999/may/25/may25-07.jpg Grows thicker.
http://www.ontariostorms.com/1999/may/25/may25-08.jpg Retracts back up...