What is the definition of a "tornado watch"?

When a tornado watch is issued, it means that conditions are conducive for the formation of tornadoes. A tornado watch covers a larger area, typically about 25,000 square miles over several hours, whereas a tornado warning covers a smaller region over a shorter time period.

A watch is issued to let people living in the area plan for a possible tornado. People in the area of a tornado watch should keep their radio and TV stations tuned into their local news or weather channel to follow any developments. During a tornado watch, people are advised to relocate their cars to a garage, move outdoor objects such as furniture inside and be aware of where the rest of the family is.