from what i understand/been told is the tornado dream means that you feel as if your life is out of control. makes sense to me, mine had been out of control for the last year and a half and i had the tornado dream on more that one occation. damn thing(s) were always chasing me. be it on the ground or when i was flying a plane.
another type of dream i can't stand is the one where your having a nightmare and you wake up, only your still asleep. yep the ol' dream within a dream thing. always scares the hell out of me!