Sherburne County ARES/RACES


Updated:Saturday January 10, 2009


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Weather  Reporting Criteria

The following is a list of weather event reporting criteria to help you know what conditions should be reported to the Sherburne County Skywarn Net Controller. Note that weather conditions must meet the following criteria in order for the event to be reported to the National Weather Service.

  • Tornado or Funnel Cloud - Location, time and direction of movement.

  • Hail - Pea-size or larger.  NOTE: When describing hail size, please do not use the term "marble" since marbles come in a variety of sizes! For the most accurate report, always report the size of the largest hailstones, preferably in terms of diameter in inches.
  • Lightning - Continuous lightning (more than 6 flashes per minute)
  • Heavy Rain - Half an inch or more per hour. Report heavy rain even if you are outside a flood-prone area.

  • Heavy Snow - We're looking for accumulations of at least four inches in 12 hours or one inch per hour.

  • Flooding - Any kind, including dam or levee failure. We need to know if the waters are rising or falling.

  • Damaging Wind - Trees or power lines knocked down, damage to buildings, etc. Report any wind of at least 40 MPH. Dictate if wind speed is estimated or measured (by an anemometer). Use the Beaufort Wind Scale to estimate wind speed.

  • Heavy Fog, Blowing Dust or Blowing Snow - Report initial onslaught of event when poor visibility impacts travel.


  • Amateur Radio SKYWARNTM Net

Instructions for All Stations: It is possible to report many types of weather information ranging from trivial to critical; however, from the standpoint of the NWS, some types of information are much more important than others. The SKYWARNTM Event Reporting Criteria listed above contain the types of information that are important to the NWS. All stations are urged to follow these guidelines when deciding what to report to the SKYWARNTM Net. Strict adherence to the SKYWARNTM Event Reporting Criteria allows vital information to be communicated as soon as possible and this in turn should allow the SKYWARNTM Net to be operated more efficiently.

Instructions for SKYWARNTM Net Control Station (NCS), Alternate NCS (ANCS), and Net Logging & Relay Station (NLRS): Stations performing Net Control Operations for the SKYWARNTM Net (the NCS, ANCS, and NLRS) need to remember that hams are encouraged to report many types of weather event occurrences during thunderstorms. While all weather reports that meet the SKYWARNTM Event Reporting Criteria are important, and need to be relayed to the NWS at some point in time, there are some reports associated with thunderstorms that are much more critical than others, and thus require a higher handling priority in terms of when to relay them to the NWS. When time is of the essence, the most critical reports need to be relayed immediately! Do not wait for additional reports before contacting the NWS, if you receive a report that requires priority handling. In other words, when receiving reports associated with thunderstorms, the reports that warrant higher handling priority should be relayed first and they need to be relayed without delay! The Priority Matrix below, categorizes weather events associated with thunderstorms by their handling priority, and should be used to determine the handling priority of weather reports. All of the weather events in the Priority Matrix require higher handling priority and must be relayed immediately to the NWS before relaying reports of weather events of lesser importance. A report of a weather event that is in the Priority Matrix is more urgent than a report of a weather event that is not in the Priority Matrix; therefore, it needs to be immediately relayed to the NWS!

Priority Matrix

Urgent Priority
High Priority
Low Priority
Tornado Hail 3/4 inch diameter or larger Hail 1/2 inch diameter
Funnel Cloud Wind Speed 58mph or greater Wind Speed 40mph or greater
Rotating Wall Cloud Persistent non-rotating Wall Cloud Cloud features suggesting storm organization
Flash Flooding Rainfall 1/2 inch + per hour Rainfall less than 1/2 inch per hour
Property damage Damaging winds (usually greater than 50 mph) High winds
(40-50 mph)


As a volunteer organization, Sherburne County Skywarn welcomes any suggestions you might have to help us serve you better.

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