We always know when a thunderstorm is coming, as our male lab goes totally nuts to the approaching storm. At least 20-30 minutes ahead of our being able to detect the storm, he starts whining, wants to hide (fireplace, bathtub, under the bed), as the storm gets closer he starts to shake uncontrollably and has had the occasional accident inside. It has become worse with age, so we now tranquilize him as soon as he starts to demonstrate panic signs.
Also, and if I had not been there, I may not have believed it. A few years ago we responded to a chest pain call. The gentleman was laying on his couch conscious and alert, his wife was nearby in the living room, his dog (I can't remember the breed) was cornered in the kitchen by a folding gate. We hooked up the cardiac monitor and were in the process of taking vitals and interviewing the patient when suddenly the dog starts howling. Within seconds the patient became unconscious and unresponsive, with v-tach showing on the cardiac monitor. Fortunately, we were able to successfully treat the patient, who eventually regained consciousness, but during the entire time the dog continued to howl. As soon as his owner regained consciousness, he stopped. It stood the hair on the back of our necks straight up the whole time. Pete