switch to velocity image

The storm in this image is a small, weak supercell which moved across northern portions of the Columbus metro.  The little notch in the reflectivity pattern on the front side of the storm is referred to as a weak echo region, and is a signature of a strong low level updraft in the storm (recall that a wall cloud forms at the base of an updraft, so this is likely where the wall cloud was spotted).  If a weak echo region is coincident with rotation, the storm could potentially be tornadic.  In this case, strong rotation was evident near the weak echo region (see velocity image), and the storm produced the rotating wall cloud seen in the photo.