Tonight it seemed louder than normal for sure. I've been hearin this for a couple years now. I've woke up my wife to hear it because she thought I was crazy. The noise is a rumbling sound that just goes away instantly , it doesn't fade away like an airplane and its not thunder. I'm not sure what it is but it's driving me nuts not knowing where it's coming from. I have a friend that works at Macdill and I asked if they were testing anything over there that would explain the noise. He said no nothing unusual. More and more people are hearing this so maybe we get some better possibilities posted.