Non-Precipitation Warnings/Advisories

The following products are all issued as Non-Precipitation Warnings/Advisories:

Freeze Advisory: Issued when the surface air temperature is expected to be 32°F or below over a widespread area for a climatologically significant period of time. These are issued until a "killing freeze" has occurred in the fall, or after April 15th in the Spring. The freeze may or may not be accompanied by frost.

Frost Advisory: Issued when a widespread frost formation is expected. Can occur with temperatures above 32°F. These are issued until a "killing freeze" has occurred in the fall, or after April 15th in the Spring.

High Wind Watch: Issued when high wind warning conditions are expected in a day or so. Rarely issued.

High Wind Warning: Issued for non-thunderstorm winds sustained at 40 mph or greater for 1 hour or more, or 58 mph or greater for any duration.

Wind Advisory: Issued for sustained winds of 30 mph or greater for 1 hour or longer, or gusts to 45 mph or greater for any duration.

Excessive Heat Watch: Issued when Heat Warning conditions are expected in a day or so. Rarely issued.

Excessive Heat Warning: Issued when the following is expected to occur: widespread Heat Index* of 115°F degrees or higher for 3 hours or more, with a minimum Heat Index* of around 80°F or higher at nighttime for a 24 hour period or longer.

Heat Advisory: Issued when the following is expected to occur: widespread Heat Index* of 105°F degrees or higher for 3 hours or more, with a minimum Heat Index* of around 80°F or higher at nighttime for a 24 hour period or longer.

Dense Fog Advisory: Issued for widespread visibilities of 1/4 mile or less for several hours due to fog.

Wind Chill Warning: Issued when the Wind Chill Index** will be lower than minus 35 for 3 hours or longer.

Wind Chill Advisory: Issued when the Wind Chill Index** will be lower than minus 25 for 3 hours or longer.

Blowing Dust Advisory: Issued when strong winds will cause blowing dust with a visibility of 1/4 mile or less for several hours.


* Heat Index: The Heat Index, given in degrees Fahrenheit, is an accurate measure of how hot it really feels when the relative humidity is added to the actual air temperature.

** Wind Chill Index: The Wind Chill Index takes into account both the temperature and wind speed. It is used to describe the rate of heat loss on the human body resulting from the combined effect of low temperature and wind.


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.