The 1948 Tinker Air Force Base tornadoes were two tornadoes which struck Tinker Air Force Base in Oklahoma City, Oklahoma, on March 20 and 25, 1948. Both are estimated to have been equivalent to F3 in intensity on the modern Fujita scale of tornado intensity, which was not devised until 1971. The March 20 tornado was the costliest tornado in Oklahoma history at the time. On March 25, meteorologists at the base noticed the extreme similarity between the weather conditions of that day and March 20, and later in the day issued a "tornado forecast", which was verified when a tornado struck the base that evening. This was the first official tornado forecast, as well as the first successful tornado forecast, in recorded history.

A tornado warning (SAME code: TOR) is a severe weather warning product issued by regional offices of weather forecasting agencies throughout the world to alert the public when a tornado has been reported or indicated by weather radar within the parent severe thunderstorm. It can be issued after a tornado, funnel cloud and rotation in the clouds has been witnessed by the public, storm chasers, emergency management or law enforcement, and indicates that residents in the affected areas should take immediate safety precautions.

A warning should not be confused with a tornado watch, issued in the United States by the Storm Prediction Center (SPC) and in other countries by applicable regional forecasting agencies or national severe weather guidance centers, which only indicates that conditions are favorable for the formation of tornadoes. Although a tornado warning is generally a higher alert level than a tornado watch, in the U.S., it can be surpassed by a higher-level alert—structured as wording that can be added to the official warning product—to warn the public of intense tornadoes affecting a densely populated area.

A tornado watch is not required for a warning to be issued; tornado warnings are occasionally issued when a tornado watch is not active (i.e. when a severe thunderstorm watch is active, or when no watches are in effect), if a severe thunderstorm develops and has a confirmed tornado or strong rotation.