When Missy and Sheldon are talking in their beds, Missy asks Sheldon how his chicken was. When her face is shown after he replies, there is a Cabbage Patch Kid next to her right arm. The next time the camera is on her, the doll is no longer there.
The county is under a tornado watch, not a tornado warning. A watch means conditions are favorable for tornadoes to form in the area. If there was an actual tornado, there would have been a tornado warning. Sheldon would have known the difference. EDIT: A watch can change to a warning as soon as a tornado is sighted. If they were near where the tornado was sighted and they were on the porch when the sirens sounded, they would not have seen the status change on the TV. They also would not have stopped to look at the TV on the way downstairs. So what was on the TV at the time was correct.
The Tornado Warning shown on TV was delivered over the Emergency Alert System, which wouldn't be created and put in use until 1997. In 1989, such a warning would have been delivered over the Emergency Broadcast System, which would break into programming with a tone, not a buzzing sound.
In the early days of the Personal Computer, very few buyers would even have known what RAM or a processor were, let alone inquire for criteria such as RAM size or processor speed.