National Weather Service United States Department of Commerce

                       

 

Product Guide: Non-Precipitation Products

There can be other hazards besides precipitation and thunderstorms.  Heat, cold, fog, dust, and wind can all have an impact.  That is why the National Weather Service issues watches, warnings, and advisories related to these hazards.


Heat Advisory (NPW)  
A "Heat Advisory" is issued when the heat index is forecast to reach between 105 and 109 degrees or air temperatures are forecast to reach between 100 and 104 degrees.  An "Excessive Heat Warning" is issued when the heat index is forecast to reach 110 degrees or higher, or air temperatures are forecast to reach 105 degrees or higher.  
Freeze Warning (NPW)  
A"Freeze Warning" will typically be issued in the spring or fall growing season if temperatures are expected to be at or below 32 degrees Fahrenheit for at least 3 consecutive hours.  In the fall, this advisory will be issued until a killing freeze occurs. Other freeze warnings may be issued for pipe-bursting freezes, and freezes after spring vegetation is already in bloom.
Wind Advisory (NPW)  
A "Wind Advisory" is generally issued for sustained winds of 25 mph or greater that will persist for an hour or more.  If caution is not exercised, the wind could be hazardous to high profile vehicles. 
High Wind Watch (NPW)  
A "High Wind Watch" is an alert to the potential for sustained winds of 40 mph or higher, and gusts to 58 mph.  A watch may be issued from 6 to 24 hours in advance of the occurrence of the event. 
High Wind Warning (NPW)  
A "High Wind Warning" is issued for sustained winds of 40 mph or higher and gusts to 58 mph. 
Dense Fog Advisory (NPW)  
A "Dense Fog Advisory" is issued when widespread visibilities are expected to be less than 1/4 mile for any extended period of time.  If temperatures are below freezing, ice could form on bridges and overpasses. 
Blowing Dust Advisory (NPW)  
A "Blowing Dust Advisory" is issued when widespread visibilities are at or below 1 mile but greater than 1/4 mile, due to blowing dust, for any extended period of time. 
Dust Storm Warning (NPW)  
A "Dust Storm Warning" is issued when strong winds produce blowing dust and visibilities less than 1/4 mile for an extended period of time.  This would only happen during a very extended dry period. 
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