Difference Between Advisory, Watch & Warning

Advisory

While advisories are for less serious conditions than warnings, they should be taken seriously. The conditions can still threaten life or property if caution is not exercised. They are issued when a hazardous weather event is occurring, imminent, or likely. 

Example: Heat Advisories are common during the summer months. During a Heat Advisory, the Heat Index is expected to exceed 105°-110°F. The heat index is what the temperature feels like when relative humidity is combined with the air temperature.

Watch

A watch is used when the risk of a hazardous weather event has increased significantly, but its occurrence, location, or timing is still uncertain.

Example: A Hurricane Watch is issued when storm conditions - sustained winds of 75 mph or higher - are possible.  A hurricane watch is issued 48 hours in advance of the anticipated onset of winds. This gives the public enough time to prepare their homes and review their evacuation plans. 

Warning

A warning means a hazardous weather event has been observed and is expected to affect the area. A warning means weather conditions pose a threat to life or property. 

Example: Hurricane Warnings are issued when sustained winds of 74 mph or greater are expected somewhere within the specific area. Warnings are issued 36 hours in advance of the anticipated onset of winds. This gives the public enough time to complete final storm prep and leave the area if directed by local officials. 

References

National Oceanic and Atmospheric Administration (NOAA). What is the difference between a hurricane watch and a warning? National Ocean Service website, January 1, 2023.

NOAA. Watch Warning Advisory Explained. National Weather Service website, accessed on August 3, 2023.

NOAA. Watch/Warning/Advisory Definitions. NWS website, accessed on August 3, 2023.

Virginia Department of Health (VDH). Hurricane Safety, VDH website, accessed August 3, 2023.