Corrected entry: At the part when they are driving in the car (near the climax scene of the big tornado) the weather radio in the car is issuing alerts about the big "F5" tornado on the ground nearby. That is a huge mistake, because there is no way to know that until a survey is done of the tornado damage afterwards. Only then can a tornado be called an "F5" or "F3".
Corrected entry: The volume of Jo and Bill's voices changes in the scene where he tries to stop picking up the Dorothy sensors that a tornado has already destroyed. When they're in the truck, they're loud probably because their dialogue was recorded in a studio later. When they're outside their voices aren't as loud because they were in the location.