What is a tornado advisory?

There is nothing that is specifically called a tornado advisory, but there are two types of advisory that relate to tornadoes.

A tornado watch is issued if overall conditions in a region favor the formation of tornadoes. Meaning there is a risk, but not an imminent threat.

A tornado warning is more serious. This means that a tornado has been spotted or detected, or that observations of a thunderstorm indicate that one is likely to form soon.

Each of these advisories has a subcategory. A PDS tornado watch (particularly dangerous situation) indicates that a system is likely to produce strong tornadoes.

A tornado emergency is an unofficial variety of tornado waring that indicates a large tornado is threatening a populated area and has the potential to cause major damage.