I've got a leak too, there is a damp circle about 12" in diameter in the ceiling about 2' in front of the door that goes out into the garage from the kitchen/dining area. My ceiling has that popcorn stuff on it. But I'm 99.44% sure that the thingie up on the roof, that turns to let heat out of the attic in the summer (single story house) is directly above the wet spot. I thought those things weren't supposed to leak? I don't remember it ever doing that before, in the 25 or 30 years since my hubby installed it.
Maybe Nolena is right about the high amounts of water and wind, and "drips"?