What was that loud boom and flash in Charles County, MD?

I live in Waldorf and at about 5:25AM on July 31,2009 I heard a really loud boom that did not come from a thunderstorm. It sounded a little identical to thunder but it wasn't exact. Later on I asked my father if he heard it, and he said no but he saw a really bright flash. Does anyone in the area know anything about what happend?