The National Weather Service Severe Weather training for 2023 will be in person. More information will follow or use the Online Skywarn Spotter Training link below.

Informal Nets | Directed Nets | Net Safety and Preparedness | Conditions | Reporting Criteria | Reporting Estimates

The county Skywarn Net is activated by the Skywarn Director whenever there is Severe Weather observed, or at the request of the White Lake NWS Office. When the Skywarn Net is activated, a Call Up process is initiated to alert all Skywarn Spotters in the area. This may include telephone calls, emails, and/or an announcement over area ham radio repeaters.

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Informal Nets may be called when a Severe Weather Watch is issued by National Weather Service, or when the National Weather Service requests it. An Informal Net alerts Skywarn Spotters to the possibility of a Severe Weather event. This allows all Skywarn stations to get their equipment ready and on the net frequency, and begin sharing informal observation reports on current conditions to track the incoming storm. Check-Ins may be held at this time to get a record of all participating stations. Again, this type of Net is usually informal and may not always precede a Directed Net. This type of Net also allows open use of the repeater by stations not directly participating in the Net.

Informal Nets may be called at anytime, and may end without observing or receiving any reports of severe weather. The important thing is to be ready if hazardous or severe weather occurs.

Once a Severe Weather event has been observed, a Weather Warning has been issued, or the NWS has requested Net Activation, a Directed Net will be called opened. When a Directed Net is opened, Skywarn traffic becomes priority traffic and the Net Control Station controls all traffic on the frequency. All non-participating stations will be asked to move any non-priority traffic to an alternate frequency until the net is closed. If the primary net control frequency is either in use by another emergency traffic net or the frequency is otherwise unavailable, the net control traffic will be moved to an alternate frequency.

During severe weather or emergency communications, there may not always be time to conduct a station check-in. If you have something to report, simply follow the reporting criteria given below. If we need information from a specific location, we will broadcast this on the air. Many times spotters can sit through an entire net lasting hours, and never give a report, and that's perfectly OK. Sometimes the best report you can give, is no report at all. We know you're out there, and we appreciate your commitment and your eyes!

Directed Nets may not always be preceded by an Informal Net. They may be called at a moment's notice and without prior warning.

Tip: If you see severe weather approaching or are aware of a Weather Watch/Warning in a neighboring County, you should begin monitoring the Skywarn repeater frequency for your county.


Safety is a fundamental consideration during Skywarn operations. We take this issue very seriously and you should too! For the safety of all and the integrity of SKYWARN, please do not engage in unsafe or unlawful behavior while in the field. The number one rule for participating in SKYWARN is...

Do not place yourself in danger to observe the weather!

Weather Spotters should not leave the safety of their homes to observe the weather. Being a Weather Spotter does not require you to go out and "chase" the storm. Your job as a Weather Spotter is to stay indoors and provide reports on your local conditions, at your home.



Under Condition GREEN, spotters may report any storm effects, at the discretion and directions of the net control station, such as:

  •  Gust front arrival
  •  Approaching thunderstorm
  •  Heavy rain, etc.


Under Condition YELLOW, spotter reports are restricted to RED reports plus other extreme storm effects such as:

  • Intense and frequent lightning
  • Hail (give approximate diameter)
  • Damaging winds (brief reports of damage observed)
  • Torrential rain (with near zero visibility)
  • Flooding over the curbs

Spotters should otherwise maintain radio silence. Check-ins and other less serious reports are not permitted under Condition Yellow.


Under Condition RED spotters should only report sightings of:

  • Tornadoes
  • Funnel Clouds
  • Wall Clouds
  • 3/4 >diameter or larger hail (dime size=3/4 inch)

Spotters should otherwise maintain radio silence. Check-ins and other less serious reports are not permitted under Condition RED.

The date and time of the event
The location of the event (major cross roads or GPS coordinates)

Warm Weather
ainfall amounts of 1 inch or more for in a 24 hour period
Hail 1/2 of an inch or greater (Dime size or greater)
Wind gusts of 40 mph or greater (please indicate whether winds were measured or estimated)
Weather related damage to buildings, trees, or vehicles

Winter Weather
Total snowfall of 1 inch or more per and storm totals
Ice accumulation due to freezing rain or freezing drizzle
Ice jams and flooding of rivers or streams

Measured reports are preferred over estimated reports, as they are generally more accurate. However, sometimes it's hard to estimate properly under severe weather conditions. Over-estimating is as bad or worse than under-estimating storm criteria.

Here is a guideline for estimating in your reports.

Hale Size

Pea Size:  
Dime Size:  
Penny Size:  
Nickel Size:  
Quarter Size:  
Golf Ball Size:  
Baseball Size:  

Rainfall Intensity

Less than 0.2"/Hr.
0.2" to 1.0"/Hr.
1.1" to 2.2"/Hr. (Min. reportable)
Very heavy:  
2.3" to 4.5"/Hr.
4.6" to 7.1"/Hr.
More than 7.1"/Hr.



Revised 12/05/22