I also think it is a temperament/nerve issue. When I was in the first grade, 5 or 6 years old, my first grade teacher brought in the clothes her husband was wearing when he was struck and killed by lightning. He had a camera around his neck and his clothes were burned through. I am terrified of thunder and lightning.
My dogs, however are not, even though they have seen me tremble and shake and even run into the house or car. So, they really do not take their cues off of me. It just doesn't phase them. And that is from puppy on up.
I was at a GSD club meeting when a conformation judge was speaking. She said that the first thing they look at is temperament. It was thundering and lightening outside. She said, of course on a night like tonight, they would take that into consideration. Well, I thought, guess who has thunder sensitivity in her lines.
I think your best bet is to watch your weather reports, and if there is a possibility of thunder or lightning, you are at home with her, with the AC on if possible, where she is most comfortable. Some dogs with storm phobias need medication. Lots of people swear by the thunder shirts.
Bear Cub, Hepsi-Pepsi
Cujo2, Karma Chameleon
Ramona the Pest, Kojak -- who loves you baby?
Tiny Tinnie, Susie's Uzzi, Kaiah -- The Baby Monster.