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Severe Thunderstorm Threat From the Central Plains to the Northeast; Extreme HeatRisk for the East Coast

Strong to severe thunderstorms are possible from the central Plains to the Northeast through this evening. Widespread damaging winds are the primary threat but hail and a tornado or two is also possible. Extremely dangerous heat continues across the Eastern U.S. Warm overnight low temperatures will provide little to no relief. Read More >

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NWR SAME Alert Duration Length FAQ

Weather.gov > NOAA Weather Radio > NWR SAME Alert Duration Length FAQ

 

  • WHAT IS CHANGING?

    NWS is adopting 99.5 hours as the NOAA Weather Radio All Hazards (NWR) Specific Area Message Encoding (SAME) maximum alert duration (aka, alert expiration time period).  The current NWR SAME maximum alert duration is 6 hours.  The new maximum alert duration will be phased in from February through June 2023 as new software is installed at NWS offices.

     
  • WHAT IS THE ALERT DURATION?

    The alert duration is the amount of time after an alert's original issue time that the alert message remains valid.  At the end of the alert duration time period the alert information will have been updated or the alert is no longer in effect.  The range of alert duration time is from 0.25 to 99.5 hours for SAME alerts.

     
  • WHAT ALERTS DOES THIS CHANGE IMPACT?

    The NWR SAME maximum alert duration change affects both Non-Weather Emergency Messages (NWEM) received via FEMA’s Integrated Public Alert and Warning System (IPAWS) and NWS watch and warning messages broadcast on NWR with the SAME alert tones.  Today, Emergency managers may choose any alert duration up to 99.5 hours in their NWEMs while the SAME alert duration is capped at 6 hours when broadcast on NWR.  The current 6-hour maximum alert duration for NWR SAME alerts is inadequate for some weather events with a duration exceeding 6 hours.  

     
  • WHAT WEATHER ALERTS ARE MOST LIKELY AFFECTED?

    The initial alert message for many hazardous weather event watches and warnings remains in effect for 6 to 12 hours or longer until the message is updated.  For example, some Blizzard Warnings and Dust Storm Warnings remain in effect for 8, 12 or 18 hours.  The initial watch or warning will now have an alert duration consistent with the first expected update time instead of being capped at 6 hours.  Another example, many flood watches and warnings remain in effect and are not updated for 12 to 24 hours after the initial watch or warning message.  This latter category includes coastal flood, storm surge, flood, river flood and some flash flood event types.
     
     
  • WILL THIS CHANGE AFFECT THE OPERATION OF MY WEATHER RADIO OR PUBLIC ALERT RECEIVER?

    The NWS is not aware of any impact on the ability of existing receivers to perform the critical alerting functions.  However, after a receiver’s alert function is activated for an alert with a duration longer than 6 hours, many receivers may not remain in the alert mode for the intended period of time or display the alert expiration or duration correctly.  Some receivers may exit alert mode immediately after the initial alert announcement.  For more information, please contact the receiver manufacturer.

    There is a significant and positive outcome in adopting the new upper limit for recipients of NWR and Emergency Alert System (EAS) alerts for weather and non-weather alerts in effect for longer than 6 hours.  EAS radio messages and television screen crawls and alert duration indicators on some weather and public alert receivers will reflect the true alert duration instead of the shortened 6-hour time period.  The NWS encourages receiver manufacturers to accommodate the 99.5 hour upper limit in new weather and public alert receivers.  The current Consumer Technology Association™  Performance Specification for Public Alert™  Receivers (CTA-2009-B) is “silent” on any upper limit for alert duration, but an updated specification expected to be published in 2023 will explicitly state the alert duration time range is from 0.25 to 99.5 hours.

    On August 4, 2022, NWS provided weather radio and public alert receiver manufacturers and EAS equipment manufacturers an early notification of the change.  NWS also asked if the planned update would negatively impact alert capabilities or performance, e.g., cause lock up or erratic operation, of any NWR SAME receivers distributed in past years or currently being distributed.  No manufacturers reported any negative impact on the alerting functions with currently supported receivers but one indicated receivers will limit the expiration time to 6 hours. 

     
  • HOW CAN I CONTACT THE MANUFACTURER IF I HAVE A QUESTION ABOUT MY WEATHER RADIO OR PUBLIC ALERT  RECEIVER?

    The NWS maintains a list of receiver manufacturers and the contact information they provide online at https://www.weather.gov/nwr/nwr_receivers#residential. 

     
  • WHY IS THE NWS ADOPTING 99.5 HOUR MAXIMUM ALERT DURATION? 

    Adopting the 99.5 hour upper limit for alert duration for NWR SAME alerts provides more consistent messaging across multiple dissemination systems. NWS overlooked adopting the maximum limit sooner.  It is also another step to reduce the risk of duplicate EAS activation by broadcaster equipment when comparing the Common Alerting Protocol (CAP) alert message received from FEMA’s Integrated Public Alert and Warning System (IPAWS) with the NWR SAME broadcast.  The current NWR SAME alert maximum duration of 6 hours is not consistent with EAS SAME and CAP alert upper limit of 99.5 hours.  Adopting the 99.5 hour upper limit for SAME alert duration will make it consistent with the current upper limit allowed by FEMA IPAWS-OPEN v4.01 Interface Design Guidance (2022 and previous versions) and the EAS CAP Industry Group’s CAP EAS Implementation Guide (2010).  The CAP EAS Implementation Guide was adopted almost in its entirety into the Part 11 EAS rules by the FCC in January 2012.  Broadcaster EAS equipment compares the alert CAP message received from IPAWS with the NWR SAME broadcast.  For a given alert, if any one of the several key elements in the CAP and SAME message are different, broadcaster equipment does not detect the messages to be for the same alert and EAS is activated again.  




 

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