Hey Redtail,
My suggestion is along the lines of 101010xxx...a small interior area, with music playing to hide the storm noises.
For one dog, we got tranquilizer pills before the 4th of July. That helped her chill out for the fire-works Bangs.
We've had dogs react to fireworks, storms, guns, the usual.
This is a good story-
Our dogs and our neighbors dogs get along very well and visit every day. Our dogs go into their house and get treats, and the same happens at our house. Their dogs come in and get treats.
A couple years ago, the neighbors were off at the hospital (having baby #2), we were all set to feed the dogs in the AM etc...
Evening of the happy event....BIG thunderstorm!
Our back door (had) a cat door in the bottom panel of the door which was 1/4 plywood. (at the time
)
Our neighbor's German Shepherd dog, clawed her way past the cat door and through the plywood to get into our house while her family was gone during a bad thunderstorm. It was a typical 5"x8"-ish flapper-type cat door. Somehow, the dog clawed enough of the door away to get into our house through the cat door.
That incident has always amazed me and also made me feel good that the dog came to our place when it was alone in a storm.