redneck thunder

(noun) When you think you hear thunder but you see no lightning and realize that it was just the engine of a large jacked-up truck. This happens commonly in the south.

(hears crackling sound) "Whoa!" "We should get out of the pool man, it must be storming. "

"Nah man, it's just redneck thunder, a bunch of people are headed to the mud bog. "

"Ah ok, we're fine then."