This collection of images represents only a few of the weather events that can have advisories, watches, and warnings. All three can be issued to one weather event, and each has a different meaning.
Click on image for full size
Images Courtesy of NOAA Photo Library, NOAA Central Library; OAR/ERL/National Severe Storms Laboratory (NSSL), NASA, and National Weather Service Forecast Office of Milwaukee/Adam Harden

Examples of Advisories, Watches, and Warnings for Weather Events

Below is a list of some weather conditions that call for an advisory, watch, or warning.

Heat Advisory/Warning: A heat advisory is issued when the daytime temperature will be 105ºF (40.6ºC) for three hours or more and the nighttime low temperatures will not be below 80ºF (26.7ºC). A heat warning is issued if the daytime temperature reaches 115ºF (46ºC) or more.

Severe Thunderstorm Watch: A severe thunderstorm watch is issued when a thunderstorm with winds greater than 57 mph (92 kph) and/or hail with ¾ of an inch (19 mm) or more in diameter is possible
Severe Thunderstorm Warning: A severe thunderstorm warning is issued when severe thunderstorms have been sighted or found on the radar. Once this warning has been issued, it is best to be prepared for lightning, heavy rain, strong winds, and large hail.
Tornado Watch: A tornado watch is issued when tornadoes may develop in a specified region within a certain time frame.
Tornado Warning: A tornado warning is issued when a tornado has been spotted or found on the radar. Shelter must be taken immediately.

Hurricane Watch: A tropical storm or hurricane is a threat to coastal areas. Be prepared to take action when a hurricane watch is issued.
Hurricane Warning: A hurricane warning is issued when a storm will strike an area within a twenty four hour time period. Wind speeds will be greater than 74 mph (119 kph).

Flash-flood Watch: Heavy rains in a specified area can cause flash flooding. A flood emergency may occur, thus it is important to be alert and prepared to take action immediately.
Flash-flood Warning: A flash flood warning is issued when a flash flood is occurring or is very probable in a certain area. Immediately move to safe ground.

Winter Weather Advisory: A winter weather advisory is issued when a low pressure system creates hazardous winter weather such as snow, freezing rain, or sleet.
Winter Weather Watch: A winter weather watch is issued when there is potential for heavy snow or large ice accumulations. The watch is typically given out 24-36 hours in advance. Criteria for a watch vary in different places.
Winter Storm Warning: This warning is issued when a winter storm is producing or is forecasted to produce heavy snow or large ice accumulations. Criteria for a warning vary in different places. Blizzard Warning: A blizzard warning is issued when there is falling or blowing snow and winds of 35 mph (56 kph) or more, causing visibility to be less than ¼ mile (.4 km) for several hours.

Last modified April 28, 2016 by Jennifer Bergman.

You might also be interested in:

Traveling Nitrogen Classroom Activity Kit

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

Thunderstorms

Thunderstorms are one of the most thrilling and dangerous types of weather phenomena. Over 40,000 thunderstorms occur throughout the world each day. Thunderstorms form when very warm, moist air rises into...more

Wind

Wind is moving air. Warm air rises, and cool air comes in to take its place. This movement creates different pressures in the atmosphere which creates the winds around the globe. Since the Earth spins,...more

Weather Radar

Radar is important to weather forecasters because it can detect rain and hail in clouds. The radar emits radio waves in all directions. When a radio wave hits water or ice particles, some of the energy...more

Thunder and Lightning

Lightning is the most spectacular element of a thunderstorm. In fact it is how thunderstorms got their name. Wait a minute, what does thunder have to do with lightning? Well, lightning causes thunder....more

Rain

Rain is precipitation that falls to the Earth in drops of 5mm or greater in diameter according to the US National Weather Service. Virga is rain that evaporates before reaching the ground. Raindrops form...more

Hurricanes (also known as Tropical Cyclones)

As a strong hurricane heads towards a vulnerable coast, people take precautions - boarding up houses, packing the car, and evacuating. These massive storms can spell disaster for people in hurricane prone...more

Sleet and Freezing Rain

Sleet forms when a partially melted snowflake or raindrop turns back into ice as it is falling through the air. This happens when there are different layers of air beneath the cloud and these layers have...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA