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Widespread Showers Across the Eastern Half of the US; Severe Thunderstorms in Montana into the Plains

Widespread coverage of showers and thunderstorms across much of the central and eastern U.S., will produce areas of excessive rain in the northwest Gulf Coast, portions of the Mississippi Valley and the southern Mid-Atlantic states. Scattered severe thunderstorms are expected from Montana into portions of the central/southern Plains this weekend. Read More >

National Weather Service Dissemination

National Program

NWR Warning

Weather.gov > National Weather Service Dissemination > NWR Warning


A: OPERATIONAL PROCEDURES

When there is an alarm on NWR, the following 4-step procedure is followed:
 

  1. A digital burst of information is broadcast. This digital burst, called Specific Area Message Encoding (SAME), contains information on the type of message, the area affected (usually by county), and the expiration time of the message. The Maximum message expiration time allowed is 6 hours after the alert.
  2. The SAME burst is followed by a 10-second broadcast of the 1050 Hertz warning alarm tone.
  3. The voice message is broadcast, describing the hazard, the area affected (usually by county), and the valid time period of the hazard. Other details, such as storm movement, storm spotter reports, damage reports, and specific locations of greatest danger may be included. NOTES about expiration time in SAME vs. valid time period in voice message:
    • For short-fuse hazards, such as a tornado warning, the valid time period is from the broadcast time of the alert until the SAME message expiration time.
    • For longer-fuse hazards, such as a winter storm warning, the beginning of the valid time period may not be the same as the alerting broadcast time and the end of the valid time period may not be the same as the SAME message expiration time. In such cases, updated messages are broadcast on or before the SAME message expiration time to provide fresh information. Updated messages will be alerted only for new warning information.
  4. A SAME end-of-alert digital burst is broadcast. For any NWR transmitter, alerting messages will only be for areas within the reception range (or coverage area) of the transmitter, assuming no use of high gain external antennas. The coverage area typically extends out to a radius of about 40 miles from the transmitter, assuming level terrain. Coverage usually includes 5 to 10 average sized counties. Hills and Mountains will reduce the coverage area.
    • Many NOAA Weather Radio receiver models can be set to a muted "standby" or "alert" mode, and will turn on when the alerting message is received. Depending on the receiver brand and model, the receiver will either be activated by the SAME code or the 1050 Hertz warning alarm tone. Upon activation, some receiver models may have a flashing light or other visual attention signal. In any case, the 10-second 1050 Hertz warning alarm tone serves as an audible attention signal.
    • For receiver models activated by the 1050 Hertz tone, the receiver will activate whenever the tone is received.
    • For SAME-decoding receivers, the owner programs the county SAME codes for the county or counties he (she) wishes to be alerted for, thereby eliminating unwanted alerts for counties in the coverage area that are not of concern to the listener.
       

B: MESSAGES ALARMED CLICK HERE for procedures on weekly alarm tests.

Only the most imminent life- and property-threatening hazards are broadcasted with the SAME signal and 1050 Hertz warning alarm tone, where the public has to take immediate action to protect themselves and their property. An operational guideline is that messages are alerted only for hazards urgent enough to warrant waking people up in the "middle of the night" or otherwise interrupting someone's activities at any time. The operational use of the SAME signal and 1050 Hertz warning alarm tone is at the discretion of WFOs, situationally-dependent and coordinated with each state's Emergency Alert System (EAS) Plan. 

The complete list of possible NWR SAME/EAS Event Codes an office may use is provided at:
 

https://www.weather.gov/dsb/eventcodes