Garland, I still don't see how John meant that, especially when he said they had one chance every year for a cover, and they blew it. How much more highlighted can you get, than the cover?
What maybe happening in that picture, and specifically the storm cloud, is, just under that darkest cell, there is a hint of a lighter shade. My guess is thats light from behind(underneath) the dark storm cell pictured. At least thats what typically happens with a lot of these storms on the plains. Many are disorganized cells that are just beginning to form and organize into the long lines of storms that I use to see in Chicago.