While researching a new vehicle for my friend in Canada, my eyes zeroed in on the wake that is visible at 4:00 - 4:01 in the video on this page :
AWD Showdown: Subaru Forester vs. Honda CR-V vs. Toyota RAV4 - Consumer Reports Video Hub
This is nearly as good as the smoke used in wind tunnels ! You can clearly see the air as it spills off the roof and follows the curve that you would see if you laid a template over the roofline.
It also shows the vortex back there.
Too bad it's only a second of the video.