I'm not the biggest fan of nature names, but I prefer Tempest over Storm/Stormy. I've heard of way too many black cats named Storm/Stormy that the name has become unusable in my mind. Tempest is still usable to me and, although destructive, there is something awe inspiring about them. The only issue I could see is if the girl has major attitude; the connection to her name would be brought up a lot!