Hi! My beloved Jingles (Rainbow Bridge) had the same thunderstorm terrors! Before it even became cloudy, she would start shaking, then head for the bathroom to hide behind the toilet. She would shake so hard and pant so hard, I thought she was going into cardiac arrest! It really frightened me and upset me to see her so terrified and unconsolable! The vet told me to try any type of positive association right before and during the storm, hoping to develop some type of positive association with the storm. It didn't help! Finally the vet put her on a mild herbal sedative ("doggiecalm") or something like that. It helped a lot to take the edge off her fear without zonking her. At this time I tried the positive re-enforcement, e.g. favorite treats, fun activities, rewards etc. and now she was calm enough to become distracted from the storm. Good luck! I know it's hard on you and hard on her. Your vet should have some good suggestions. I'm also going to check out a website I think has some info. re: thunderstorm terrors!!