What warning product indicates that a tornado has been spotted or indicated on radar?

A tornado warning indicates that a tornado has been spotted or indicated on radar.

The National Weather Service issues a tornado warning when a tornado is occurring, imminent, or detected through reliable evidence such as a trained spotter report or radar-indicated rotation. The warning identifies the threatened area and tells people there to seek shelter immediately, usually in a basement or an interior room on the lowest floor of a sturdy building.

A tornado watch has a different purpose. It means that atmospheric conditions are favorable for tornadoes across a broader area, but a tornado has not necessarily formed. A warning is more urgent and normally covers a smaller, specific location. Radar can detect the rotation associated with a developing tornado even when heavy rain, darkness, or distance makes visual confirmation impossible.

A tornado emergency is not the basic warning product. It is an enhanced alert used in especially dangerous situations, typically when a confirmed large or destructive tornado is affecting a populated area. A severe thunderstorm warning covers dangerous thunderstorms, but does not by itself indicate a tornado.