Bobcat. Have those in abundance here in SW Ga. Most I have seen were gray in color. Mountain lions/Florida Panthers have really long tails and often sport collars by wildlife agencies.
I heard one scream once when I lived in Pennsylvania. Very terrifying. Like the scream when Earth, Wind, and Fire recorded a song and next door to the recording studio, a lady was murdered in a knife attack. Her blood curdling scream was recorded in the sound track.
After looking at different pictures, its probably a bobcat, seems to be skint up a little. Just doesn't look like most bobcats I have seen, more sleek and lean, probably just its summer coat.
big but not cougar big, either a bob cat or i wouldnt even rule out someones pet, with all the Bengal and Savannah cats that are around nowadays domestics can get pretty ****ing big