Thunderstorms are prevalent in the south during the summer. I know that some dogs simply don't like thunderstorms because of the noise and the lowering of barometric pressure. I've heard of dogs that run into closets or under beds. We've been fortunate in that our dogs have adjusted to thunderstorms. They seem to take the noise in stride.
However, Stella and Mia seem to be two that don't like storms at all. Both begin to show distress by panting heavily. Stella wants to be with her human and stick right at his side. There are a couple of suggestions for how to possibly alleviate fear of storms.
One of the things is to provide a crate as a haven for a dog during the storm. Cover the crate with a blanket and let the dog relax in the crate. Talk to the dog in a reassuring manner while the dog is in the crate. Behaviorists claim that purchasing a CD of storm noises and playing it during the day, gradually increasing the volume can help to modify behavior. Personally, I think that Labradors would recognize a recording from the real thing. It is suggested that if you get a recording, reward the dog with a special treat for not panting and showing signs of fear. If you increase the volume, watch to see how the dog reacts. If the dog becomes anxious, then lower the volume and after the dog calms down, then try raising it again and leaving it raised for a few minutes. Then lower the volume again. I've read that this works but have never tried it.
As a last resort, there is also medication that can be given. However, given that thunderstorms arise quickly down here, I don't think that would be much help either.
Probably the most important thing is to calm the dog as much as possible. Let him go into a darkened crate if he wants, but if he wants to be near you, then let him. Hopefully, the dog will get used to the fact that thunderstorms roll through fairly quickly.