If you look, you will see red and green. On color represents wind blowing to the direction of the radar site, the other represents wind blowing away from the radar side. Normally, looking at the base velocity from a radar site, one half will be green the other half red. To see the green in the sea of red like that is a pretty strong indication of rotation and as intense as that looks I'll bet there is a twister on the ground in that area.