Yep, it's lightning and thundering.
And if I start to think that's weird, last year on November 12th*, we had a tornado outbreak that killed someone and nearly wiped a couple of towns off of the map (I was out of town, and had a hyperventilating moment myself, when it looked like the area of town where I live had been hit, but it turned out to be a mistake on the news). My lab monitors could see it from the lab, though.
So, it's not unheard of...
* Holy crap - there's a Wikipedia entry for it?