Downdrafts (called "microbursts" by the weatherguessers) can indeed create those patterns. They can be incredibly powerful, but very localized. Some have brought down airplanes. The idiot media calls them "wind shear" without further explanation. Microbursts are common in strong storms like you describe.
If you can, try to find pictures of the trails tornados leave in fields as they pass. It's very interesting...almost looks like they were made with a pencil.