I don't see anything in that cloud, but I live in North Florida and I remember seeing this storm. It was ESE from my home and on the day it occurred, I could only see the frequent lightning through the trees around my place. I remember going in and calling up the NWS radar and noted a very small area of light to moderate rain in the direction of the storm I was seeing. It was early evening with the sun low in the west, the sky was deep blue and cloudless, except for this area. I've lived in Florida for nearly 50 years and have seen some really odd lightning storms, but nothing like this one and I am glad it got recorded. It was phenomenal indeed!