Hi,
We had another 3 inches of fluffy snow last night, and I took the highway, which was running about 40 mph to work instead of the back roads.
As soon as I got out of the car and stooped down to look at the underside of the tail, I saw what I was looking for! A nice patch of snow of stuck to the underside, giving a clear indication of air flow and turbulence.
Note: there was a 10/15 mph or so sidewind from left to right, for most of the drive, and that sidewind caused the shifted pattern that you see in the pictures.
I'm a little surprised that there is not more snow sticking to the side of the tail by the side tail lights, since the sidewind was pretty stiff, and could potentially cause turbulence on this side of the tail??
Enjoy, Jim.