A watch lets you know that weather conditions are favorable for a hazard to occur. It literally means "be on guard!" During a weather watch, gather awareness of the specific threat and prepare for action - monitor the weather to find out if severe weather conditions have deteriorated and discuss your protective action plans with your family.
A warning requires immediate action. This means a weather hazard is imminent - it is either occurring (a tornado has been spotted, for example) - or it is about to occur at any moment. During a weather warning, it is important to take action: grab the emergency kit you have prepared in advance and head to safety immediately. Both watches and warnings are important, but warnings are more urgent.
- Tropical Storm Watch: An announcement that tropical-storm conditions are possible within the specified area.
- Hurricane Watch: An announcement that hurricane conditions are possible within the specified area. Because outside preparedness activities become difficult once winds reach tropical storm force, watches are issued 48 hours in advance of the anticipated onset of tropical-storm-force winds. Action: During a watch, prepare your home and review your plan for evacuation in case a Hurricane or Tropical Storm Warning is issued. Listen closely to instructions from local officials.
- Tropical Storm Warning: An announcement that tropical-storm conditions are expected within the specified area.
- Hurricane Warning: An announcement that hurricane conditions are expected within the specified area. Because outside preparedness activities become difficult once winds reach tropical storm force, warnings are issued 36 hours in advance of the anticipated onset of tropical-storm-force wind. Action: During a warning, complete storm preparations and immediately leave the threatened area if directed by local officials.
- Extreme Wind Warning: Extreme sustained winds of a major hurricane (115 mph or greater), usually associated with the eyewall, are expected to begin within an hour.Action: Take immediate shelter in the interior portion of a well-built structure.
Additional Watches and Warnings may be issued to provide detailed information on specific threats such as floods and tornadoes. Local National Weather Service offices issue Flash Flood/Flood Watches and Warnings as well as Tornado Warnings.
Reference: NWS National Hurricane Center