warning

noun

1. the act or utterance of one who warns or the existence, appearance, sound, etc., of a thing that warns.
2. something that serves to warn, give notice, or caution: We fired a warning at the intruders.
3. Meteorology. an announcement from the U.S. National Weather Service alerting the public that a storm or other weather-related hazard is imminent and that immediate steps should be taken to protect lives and property.Compare advisory(def 5), storm warning(def 2), watch(def 20).