The NWS broadcasts weather warnings and Non-Weather Emergency Messages (NWEMs) via NWR and NWR serves as a primary source of information for the nation’s EAS.
Both NWR and EAS are generally viewed as county-based systems. However, this is particularly problematic for very large or uniquely-shaped counties because even if only a small portion of a county is included in a warning, the warning’s NWR and EAS dissemination translates to the entire county.
However, both NWR and EAS allow a county to be divided into fixed partitions, with the number of partitions ranging from two to nine. Each partition is associated with a unique, six digit location code. Five WFOs (Duluth, Glasgow, Las Vegas, Rapid City and Tucson) successfully assigned partial county codes to one or more of their counties. We refer to this more-targeted dissemination of polygon-based warnings via NWR and EAS as Partial County Alerting (PCA).
The implementation of PCA for a county must first be agreed to by local officials, emergency managers, and broadcasters.
If PCA is implemented, NWR listeners with Specific Area Message Encoding (SAME)-equipped receivers carrying the Public Alert™ logo can easily select a unique, six digit location code for their local area and receive automated notifications of WFO-issued warnings.
In addition, based on WFO decisions with local officials and emergency managers, PCA may be used for NWEMs.
When WFOs implement PCA, a Service Change Notice will first be issued to specify if PCA will be used for weather warnings, only, or for weather warnings and NWEMs. Maps will be posted on WFO web pages detailing partition boundaries and associated SAME location codes.
The operational implementation of PCA is an opt-in service for those who wish to receive warnings more applicable to their local area. If NWR listeners using Public Alert™ receivers wish to continue receiving all warnings for their county, they do not need to make any SAME location code changes.
Here is a graphical depiction of PCA for a county “before” and “after.”
The NWS’s proposed national expansion of PCA includes the following enhancements:
Note that PCA does not result in the direct dissemination of a forecaster-defined polygon (or a NWEM defined by a polygon) via NWR and EAS. However, the implementation of PCA will reduce our warning footprint on NWR and EAS from the entire county to one more closely representing the area defined by the polygon warning (or a NWEM defined by a polygon).
To receive the benefits of this enhanced dissemination capability, consumers must use a SAME-equipped NWR receiver and program in the six digit code associated with a county partition. Details on programming receivers for partitioned counties are online at weather.gov/nwr/sameenz
The six digit location code for a county partition will be provided on the national NWR county pages.
The national NWR web pages (http://www.weather.gov/nwr) provide more information about SAME and a list of NWR receiver manufacturers.
WFO NWR webpages will also contain more detailed information on their use of PCA and the six digit location codes for partitioned counties.
Please submit any comments, suggestions or questions to:
Mr. Timothy Schott
Meteorologist
National Weather Service Headquarters
1325 East-West Highway, Station 14440
Silver Spring, Maryland 20910
Email: Timothy.Schott@noaa.gov
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