National Weather Service United States Department of Commerce

What is SKYWARN™?

The effects of hazardous weather are felt every year by many Americans. To obtain critical weather information, NOAA's National Weather Service (NWS), part of the U.S. Department of Commerce, established SKYWARN™ with partner organizations. SKYWARN™ is a volunteer program with nearly 290,000 trained severe weather spotters. These volunteers help keep their local communities safe by providing timely and accurate reports of severe weather to the NWS.

In the average year, 10,000 severe thunderstorms, 5,000 floods and more than 1,000 tornadoes occur across the United States. Southern New England is no exception with major weather events such as Superstorm Sandy, the Revere Tornado of 2014, the floods of March 2010, and numerous blizzards including the latest of February 2013. These events threatened lives and property and because of this we rely heavily on our SKYWARN™ volunteers who call the NWS in Norton, MA to report certain weather conditions. Since the program started in the 1970s, the information provided by SKYWARN™ spotters, coupled with Doppler-radar technology, improved satellite and other data, has enabled NWS to issue more timely and accurate warnings for tornadoes, severe thunderstorms and flash floods.
SKYWARN™ storm spotters are part of the ranks of citizens who form the Nation's first line of defense against hazardous weather. There can be no finer reward than to know that their efforts have given communities the precious gift of time--seconds and minutes that can help save lives. While the main role of a storm spotter is to be their community's first line of defense against dangerous storms, they also provide important information to NWS warning forecasters who make critical warning decisions. Storm spotters play a critical role because they can see things that radar and other technological tools cannot, and this ground truth is critical in helping the NWS perform our primary mission, to save lives and property.


                                        2024 Spring SKYWARN Classes 

Each participant should register separately 

                                            Date/Time                                     City/State                        Venue                         Registration

Classes have concluded for the 2024 season. Check back in March for the Spring 2025 schedule!

NEW FOR 2024: NWS Boston is no longer issuing individual SKYWARN numbers or requiring re-training every 5 years in order to remain a spotter.

While we encourage spotters to retrain periodically, it is not required to continue to provide reports. 



Below are few resources hosted locally at the National Weather Service in Norton, MA, as well as National and Amateur Radio resources concerning SKYWARN™.


Forecasters from the National Weather Service (NWS) in Norton conduct storm spotter training sessions each year to help prepare spotters for the upcoming severe weather season. These sessions are free and open to anyone who is interested in learning about hazardous weather and the role of a spotter. 

Our live training sessions are 1.5-2 hours in length, and once you complete the training, you will be an official SKYWARN™ spotter. This goal of the training is to train spotters to assist local officials and the NWS with early detection of hazardous weather, and provide ground truth during severe weather events. The learning objectives of our live training sessions are:

  • Understand the how the NWS Integrated Warning System works and how the spotter fits into this system
  • Identify the ingredients needed for organized thunderstorms
  • Recognize the visual and environmental clues suggestive of severe weather
  • Distinguish between legitimate clues and non-significant features associated with severe weather
  • Learn how to stay safe when storm spotting
  • Learn proper storm reporting procedures
Approximately one-third of NWS-Norton's spotters also are amateur radio operators. This dual role can be helpful, especially during a major storm such as a hurricane, when phone and power lines are downed and amateur radio may become the primary means of communications.
SKYWARN™ volunteers also help the NWS by reporting winter weather, flash flooding, coastal flooding, etc., according to the established criteria. It must be stressed that we are looking for reliable and objective reports. When snowfall reports are inflated or hail sizes are exaggerated, for example, it can do more harm than good. While not a requirement, it is preferred that our SKYWARN™ volunteers would be available to receive a call from the NWS, in the event we feel that something suspicious is happening in their area. 

Training sessions are held throughout southern New England, typically in the late spring and early summer months. The latest training dates can be found on the Training Schedule tab just above. One can also find announcements on our website or on social media.

Relationship to COMET Training

We understand that some SKYWARN™ training courses are available through COMET (the Cooperative Program for Operations Meteorology, Education, and Training) entitled "Role of the SKYWARN™ Spotter" and "SKYWARN™ Convective Basics". While these are instructive, they do not meet the requirements to become a NWS-Norton SKYWARN™ Spotter. In order to become a NWS Boston/Norton SKYWARN™ spotter, it is necessary to attend one of the in-person training classes offered, usually in the spring and early summer. If you cannot attend an in-person class, you may watch the Virtual Training


Spotter reports help the NWS in the warning process. Your report becomes part of the warning decision making process, and is combined with radar data and other information and used by NWS forecasters to decide whether or not to:
  • Issue a new warning
  • Cancel an existing warning
  • Continue a warning
  • Issue a warning for the next county
  • Change the warning type (from severe thunderstorm to tornado, for example)
For your reports to be the most useful, they should be as detailed, concise, accurate and timely as possible. Your severe weather report should address the following questions:
  • WHAT did you see?
  • WHERE did you see it?
  • WHEN did you see it?
Report the location/approximate location of the event. Be sure to distinguish clearly between where you are and where the event is thought to be happening (i.e., "I'm 5 miles north of Bristol. The tornado looks to be about 5 miles to my northwest"). Be sure that reports that are relayed through multiple sources carry the time of the event, NOT the report time.

Any other details that are important - How long did it last? Direction of travel? Was there damage? etc.

Although reporting criteria may vary slightly depending on the spotter network and local needs, the significant weather elements below (Severe, Hail, Wind, Winter) are ones the National Weather Service (NWS) would like to know about as soon as possible. Again, reports should provide as much detail as possible to describe the where, when, how, etc., of the event.
Weather Event Report Criteria What Specifically to Report
FUNNEL CLOUD   Organized, persistent, sustained rotation
WALL CLOUD   Organized, persistent, sustained rotation
HAIL Pea-size or larger Report the largest size hailstone
WIND GUSTS 40 mph or higher Specify estimate or measurement
STORM DAMAGE   Damage to structures (roof, siding, windows, etc)
Damage to vehicles (from hail and/or wind)
Trees or large limbs down
Power/telephone poles and/or lines down
Damage to farm equipment, machinery, etc.


Commonly used hail sizes are provided below. As a reminder, spotters are encouraged to report pea-sized hail or greater.
Hail Type Hail Size
Pea 0.25 inch
Half-inch 0.50 inch
Dime 0.75 inch
Nickel 0.88 inch
Quarter 1.00 inch
Half Dollar 1.25 inch
Ping Pong Ball 1.50 inch
Golf Ball 1.75 inch
Hen Egg 2.00 inch
Tennis Ball 2.50 inch
Baseball 2.75 inch
Tea Cup 3.00 inch
Grapefruit 4.00 inch
Softball 4.50 inch

Weather Event Report Criteria What Specifically to Report
  • Storm Total of 2 inches or more
  • One inch or more in 1 hour
  • Flooding that impacts roads, homes or businesses. Streams or Rivers are near bankful.
  • Minor, moderate or major coastal flooding
  • Ice jams

General guidelines for estimating wind speeds are below. As a reminder, we encourage spotters to report wind gusts of 40 mph or greater.
Wind Speed Typically Observed Damage
30-44 mph (26-39 kt) Whole trees in motion. Inconvenient walking into the wind. Light-weight loose objects (e.g., lawn furniture) tossed or toppled.
45-57 mph (39-49 kt) Large trees bend; twigs, small limbs break and a few larger dead or weak branches may break. Old/weak structures (e.g., sheds, barns) may sustain minor damage (roof, doors). Buildings partially under construction may be damaged. A few loose shingles removed from houses.
58-74 mph (50-64 kt) Large limbs break; shallow rooted trees pushed over. Semi-trucks overturned. More significant damage to old/weak structures. Shingles, awnings removed from houses; damage to chimneys and antennas.
75-89 mph (65-77 kt) Widespread damage to trees with large limbs down or trees broken/uprooted. Mobile homes may be pushed off foundation or overturned. Roof may be partially peeled off industrial/commercial/ warehouse buildings. Some minor roof damage to homes. Weak structures (e.g., farm buildings, airplane hangars) may be severely damaged.
90+ mph (78+ kt) Many large trees broken and uprooted. Mobile homes damaged. Roofs partially peeled off homes and buildings. Moving automobiles pushed off the road. Barns, sheds demolished.


Observations are not limited to summer storms only. The NWS is especially interested in reports when snow is falling and radar echoes are not always able to detect the amount of snowfall and conditions on the ground. Please pass on the following information to your weather service office:
Weather Event Criteria
Winter Weather
  • Precipitation type changes (rain to sleet/freezing rain/snow, when the change has "taken hold")
  • Thunder, when accompanied by snow
  • 1/4-inch radial ice accretion (from twig outward; not circumference)
  • Snowfall amounts 2-inches or greater
  • If snowfall rates are1-inch per hour or greater
  • Final snowfall total immediately at the end of the storm



Do I get a Spotter card?ExpandCollapse

NWS Boston/Norton will issue spotter cards to spotters at in-person classes. This card contains the reporting phone number and reporting criteria but no individual "spotter number" as in years past.  

How do I become a member of SKYWARN™?ExpandCollapse

SKYWARN™ is not to be considered a club which requires membership. It is the concept of using volunteer storm spotters to provide critical information to local communities and to the NWS, and that is what has driven the storm spotter program since it began decades ago. Your community may have an organized storm spotter network that uses the name SKYWARN™, and you should contact your local emergency manager to find out what formal spotter networks are in place near you.

Do I need an amateur radio license to be a storm spotter?ExpandCollapse

No, you do not have to be an amateur radio operator to make a weather report. However, many spotter networks are made up of dedicated amateur radio operators who use radio to coordinate their local network and to relay reports to the NWS.

How do I report severe weather?ExpandCollapse

Feel free to give us a call on the 1-800 number listed on your spotter card (or given at the end of the virtual training). You can also give us your report through our online reporting form. If you by chance take any pictures or ideas of hazardous weather across southern New England, you can post that information on our Facebook and/or X(Twitter) accounts.

How long are the classes and are they free?ExpandCollapse

The SKYWARN™ classes generally run about 2 hours long. They are free and open to the public. Registration is required.

If I have additional questions, who do I contact?ExpandCollapse

Please feel free to contact Bryce Williams