Weather Spotter

The National Weather Service is continuously recruiting spotters!

Weather reports from spotters will help save lives and property during the years to come. The volunteer spotter team is an essential part of the warning decision process of the National Weather Service. Ground truth reports from spotters are used in conjunction with Doppler radar, satellite, and other sources to determine the need for weather warnings and advisories.

Become a Weather Spotter

The National Weather Service Boulder/Denver is hosting an upcoming virtual weather spotter class.

  • Thursday, May 13
  • 6:30-8:30 p.m.
  • This is a virtual class using GoToMeeting
  • You will receive instructions after registering for the class

Register here.


  1. The National Weather Service (NWS) in Boulder has tools to see storms including Doppler radar, satellite images, and rain gauges. Spotters report hail size, rainfall rates, the extent of flooding, funnel clouds and tornadoes, snowfall, peak wind gusts and wind damage, etc. Spotters provide ground truth and help the NWS put out accurate warnings and forecasts.
  2. A trained spotter can help their business or community by providing the early notification of a dangerous weather situation.
  3. Spotter training keeps the spotter and family safer when severe weather threatens.

What Is It?

  1. Most spotter training is hosted for the public by local emergency managers or fire departments. Spotter training can be scheduled for other organizations. There is no charge for the training.
  2. Training from the Boulder NWS office is normally conducted from March to May.
  3. Training sessions are about two and a half hours in length.
  4. There are 20 to 30 public sessions each spring, so anyone interested in training should be able to attend a training session nearby. The public spotter training schedule is posted on the NWS Boulder website. Check back occasionally as new classes are added frequently.

What Is Included in the Training?

  1. Severe weather (hail, tornadoes, damaging winds, flash flooding).
  2. Severe weather safety.
  3. National Weather Service watches, warnings, and the flow of information before and during severe weather. How warnings are issued and the importance of spotter information in the warning process.
  4. Thunderstorm structure (updrafts, downdrafts, inflow, outflow).
  5. Types of thunderstorms and how their structure varies.
  6. What to look for in a rotating storm.
  7. Types of tornadoes and how they develop (supercell and non supercell)
  8. Cloud features and what they indicate from different distances and locations from the storm.
  9. What makes Colorado special? We include local information on the role topography plays in contributing to the severe weather and flooding in northeast Colorado.
  10. Anyone who signs up becomes part of the Colorado All-Season Spotter Team (CAST). CAST spotters receive their own spotter identification number and instructions on what to report and how to report it to the National Weather Service.