Fox News Weather Center

The Difference Between Tornado Watches and Warnings

When severe weather is approaching, watches and warnings are issued to inform the public of impending threats. There is a distinct difference between a watch and a warning, and knowing the difference can save your life.

"Watches, like severe thunderstorm watches and tornado watches, which are two of the most common types, are issued when weather conditions are conducive for the event to occur," Senior Meteorologist Mike Pigott said.

The Storm Prediction Center (SPC) defines a "severe thunderstorm watch" by outlining an "area where an organized episode of hail one inch in diameter or larger and/or damaging thunderstorm winds are expected during a three- to eight-hour period."

A "tornado watch," for example, includes the "large hail and damaging wind threats, as well as the possibility of multiple tornadoes," according to the SPC. Typically, most watches cover roughly 25,000 square miles.

Watches are issued by the SPC. Warnings are issued by local National Weather Service (NWS) stations.

"Warnings are different. A warning is issued when the weather event is happening now," Pigott said. "In terms of flooding, for instance, a flood warning means a river has spilled over or flash flooding is occurring."

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"Basically, a watch means atmospheric conditions are right for it to happen. Warnings mean it's actually happening," Pigott said.

A tornado warning means that a tornado has already been detected.

"A (tornado) warning means your life and property are in danger. When a warning is issued, move indoors, preferably to the basement. If no basement, interior rooms or the bath room can offer protection. The pipes add strength to the structure there," Chief Forecaster Elliot Abrams added.

Information for this story was provided by the SPC and the NWS.