Hi I'm Rosie one of the vets and I'd like to try and help you and Clementine. I'm sorry she's not well at the moment. There are a few things which can cause panting. Fear/stress is definitely one of them - it is entirely possible that she heard the storm before and after you did (dogs have great ears
usually) which made her afraid which made her pant. Dogs can also pant because they are in pain - for example most arthritic labradors pant from the constant ache of arthritis
, and it is something which people bring up in consults quite a bit. Hidden internal problems that cause pain can also cause them to pant, such as liver enlargement (for example from a tumour). In this situation she would probably be intermittently panting over several months rather than the type of panting which you describe.
There are a couple of more worrying concerns for panting. Dogs can pant when there isn't enough oxygen in their system. One of the key signs of a sudden onset internal bleed is a patient who is panting (I ran an emergency clinic for a couple of years and saw quite a few of these). Another type of panting is when a dog, for whatever reason (lung or heart problems) cannot breathe properly so cannot get enough oxygen into the system.
I think that on the basis that the panting is concerning enough for you to ask about it, and therefore must be quite noticeable, it would be worthwhile getting her checked out by a vets. If your vet isn't open I would find an emergency clinic. I wouldn't necessarily panic, as she could have just been scared by the thunderstorm, but I would hate to assume that was the problem and ignore something more serious. If it is caused by a bleed or a lung problem then obviously the sooner you get her looked at, and treatment started, the better.
I hope I've helped - if you have any questions from this then just hit 'reply' and I will get them and get back to you. Otherwise please leave a positive rating.
Thank you, ***** ***** luck, Rosie.