Storm Prediction Center - Weather Watches

Weather Watches

Watches (WWs) issued by the SPC are generally less than 20,000–50,000 square miles (52,000–130,000 km2) in area and are normally preceded by a mesoscale discussion. Watches are intended to be issued preceding arrival of severe weather by 1–6 hours. They indicate that conditions are favorable for severe thunderstorms or tornadoes. In the case of severe thunderstorm watches organized severe thunderstorms are expected but conditions are not thought to be especially favorable for tornadoes, whereas for tornado watches conditions are thought favorable for severe thunderstorms producing tornadoes. In situations where a forecaster expects a significant threat of extremely severe and life-threatening weather, a watch with special wording of "particularly dangerous situation" (PDS) is subjectively issued. It is occasionally issued with tornado watches, normally for the potential of major tornado outbreaks. A PDS severe thunderstorm watch is very rare and usually issued for the potential of major derecho events.

Watches are not 'warnings', where there is an immediate severe weather threat to life and property. Although severe thunderstorm and tornado warnings are ideally the next step after watches, watches cover a threat of organized severe thunderstorms over a larger area and may not always precede a warning. Warnings are issued by local National Weather Service offices, not the Storm Prediction Center, which is a national guidance center.

Watches are canceled by the local National Weather Service office.