I had a spaniel that was the bird dog of late DH's dreams and was exstatic at the sound of gun fire. "Oh boy let's go hunting!" However as she aged and wasn't hunting anymore she became more and more agitated with storms. She definitely knew a storm was coming long before I did and I assume that it is either the abrupt change in atmospheric pressure or the electrical field she sensed. She would suddenly become a lap dog which was not her normal pattern. As she aged she was deaf as a post so it wasn't the noise. I used Benadryl and the vet approved. She was still frightened but not nearly so much. I have a neighbor whose Brittany, only as old age took over, panicked when storms approached. She too was deaf. They finally resorted to a prescribed sedative and it was the humane thing to do.