I once worked for Severe Storms Laboratories during one thunderstorm/tornado season. One night things were really popping. I was at the Piedmont site and El Reno reported a funnel cloud. Ra-ob control radioed us and said it was coming right for us. It was dark, dark, dark. We couldn’t see a darn thing until the lighting struck. We could hear it, and it kept getting louder as it approached. I was scared. It missed us a bit to the north, but we never saw it.
Nothing like hearing an approaching tornado at night. Shivvers..
In my experience, you still can't tell what you are seeing in the lightening flash. Especially rain wrapped funnels. Just flash light and blackness.