National Weather Service United States Department of Commerce

NWS Phoenix SKYWARN/Storm Spotter Program

South-Central & Southwest Arizona and far Southeast California (map)

When significant, or severe weather occurs anywhere within the Phoenix County Warning Area, the Weather Service turns to the SkywarnTM Spotter Network to obtain timely and accurate reports. This network is comprised of individuals or groups, generally associated with the following: 1) Emergency Service Organizations (Fire, Police, etc), 2) Volunteer Organizations (HAM Radio, Citizens' Band Radio, etc), 3) Individual Citizens, 4) Cooperative Observers.  

Even with sophisticated technology like radar and satellites, there are a variety of atmospheric phenomena that require the human eye to detect and/or confirm.  This information is called "ground truth" and is provided by trained weather spotters throughout the year.  When hazardous weather occurs, Spotters provide detailed eye witness descriptions of the conditions to the local National Weather Service office by means of the Web, email, phone, or amateur radio.  Spotters in Southern Gila, La Paz, Maricopa, Northwest Pinal, Yuma, Imperial (CA), and Eastern Riverside (CA) counties should report to the Phoenix forecast office.  Click here for a map.

Spotters should provide the following information:

  • WHO they are (Spotter ID)
  • WHAT they saw or are seeing,
  • WHERE they are or where they were when it was going on.
  • WHEN the reportable conditions were first observed.

Reporting Criteria

The following criteria are what spotters should report to the National Weather Service - Phoenix. 

  • Tornado (on the ground)
  • Funnel Cloud (tail NOT touching the ground)        
  • Storm Damage (deaths, injuries, broken tree limbs, shingles off roofs, etc.)
  • Flooding (streets, running washes, etc.)
  • Low Visibility (less than 1 mile due to dust, sand, fog, etc. - except rain)
  • Rotating Wall Cloud
  • Heavy Rainfall (measured ½ inch or more accumulation in 30 minutes or less)
  • Hail  (diameter of largest stone - any size)
  • Snow (accumulating or not)

Reporting Methods

Trained Spotters should utilize the methods outlined in the class (webpage, email, phone, radio).  For those who are not trained Spotters, you can send us a Tweet or post to our Facebook page. 




To become a Skywarn Spotter for the NWS Phoenix office requires attending a free one hour training class. Our office conducts Spotter classes at locations throughout our forecast area.  Typically, this occurs during the March through May time frame. 

The classes teach people how to properly identify and report significant weather phenomena and thereby contribute to public safety.  You will learn about how thunderstorms work, how to identify cloud features associated with microbursts and tornadoes, and how your reports tie in to warnings and advisories issued by the National Weather Service (NWS).  In addition, you will learn about all of the services available from the NWS.  

Adult SKYWARNTM volunteers are community minded individuals who understand that they play a role in public safety by providing storm information to the National Weather Service.

If you have any questions, please contact either Austin Jamison or Marvin Percha at 602-275-7418 at the NWS Phoenix Forecast Office. 

*** We especially need new spotters in more rural areas of our forecast area (County Warning Area - CWA)***


Training Class Schedule


***Classes below are Webinars***


Date Time Registration Notes

November 10

630pm - 730pm


Open to residents of our forecast area (Map)

Standard class (online webinar)

November 12

630pm - 830pm


***Open only to current Spotters for NWS Phoenix***

Advanced class (online webinar)

***Must have completed the Standard class in either 2019 or 2020***











Amateur Radio ("HAM" radio)

When a Skywarn Net has been activated for public safety purposes, trained Spotters who are amateur radio operators may submit storm reports by radio. There are also weekly routine Nets utilizing the same frequencies (see below).  These routine Nets are a good way to test how readily you can connect to those repeaters as well as practice interacting with a Net Controller. For questions specific to amateur radio, contact Marvin Percha ( 

Maricopa and Pinal Counties:

  • 147.200 MHz  (PL Tone 162.2)  --  Tuesdays at 8 pm

  • 442.550 MHz (PL Tone 100.0)  --  Wednesdays at 8 pm

Yuma and eastern Imperial Counties:

  • 146.780 MHz (PL Tone 103.5)  -- Tuesdays at 7 pm


Educational Resources


Class Study Guide (pdf 336KB)


PDF version of PowerPoint presentation (pdf 18.4 MB)


Spotter's Guide (pdf 27.2 MB):


JetStream - an Online School for Weather


MetEd (hundreds of online tutorials for the GeoScience community)


Radar Basics (pdf 7MB)


Radar Tutorials

  • Introduction to the WSR-88D system
  • Principles of Radar
  • Velocity Interpretation
  • Base and Derived Products
  • Convective Storm Structure and Evolution
  • Flash Floods
  • Winter Applications


NWS Norman Spotter Resources (emphasis on Great Plains severe weather)

  • Training Videos (informational - not a substitute for NWS Phoenix classes)


NSSL’s HotSeat Warning Simulator



Additional Useful Links


Rainfall Data Sources


NWS Publications and Brochures 


Climate Sites


Drought Sites