What is the difference between a tornado watch and a tornado warning? Prentice Hall - Science Explorer.

A tornado watch indicates that conditions are favorable for a tornado to form and that people in the affected area should remain watchful in case a tornado forms.

A tornado warning means that a tornadic cloud (whether it touches down or not) has been indicated by doppler radar, or sighted, in a given area and people in the affected area should take appropriate action to remain safe.