National Weather Service United States Department of Commerce

Partial County Alerting for NOAA Weather Radio (NWR) and the Emergency Alert System (EAS), with new service enhancements, begins in 2023 for select US counties

The National Weather Service (NWS) broadcasts weather warnings and Non-Weather Emergency Messages (NWEMs) via NWR. NWR also serves as a primary source of information for the nation’s EAS.

The challenge:

NWR and EAS are both generally viewed as county-based systems. However, this is particularly problematic for select 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. This issue is most common for very large, uniquely-shaped (e.g., rectangular) or uniquely-configured (e.g., islands) counties.

What NWS has done until now:

Both NWR and EAS allow a county to be divided into several fixed areas (partitions). Each partition is associated with a unique, six digit location code. Five WFOs have successfully assigned partial county codes to one or more of their counties (most recently by WFO Las Vegas for Clark County, NV). Details on what each of these WFOs are already doing are available through the link on the right side of this page. We refer to this more-targeted dissemination of warnings via NWR and EAS as Partial County Alerting (PCA). PCA implementation is not appropriate for every US county. The usefulness of PCA is generally reserved for very large or uniquely-shaped counties, such as elongated counties.

How Partial County Alerting improves information delivery via NWR and the EAS:

When 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 only for the programmed partition(s). PCA reduces “listener fatigue” by reducing the receipt of warnings for distant parts of a county.

With PCA, broadcasters may choose to limit the activation of EAS to specific county areas.

How is Partial County Alerting changing beginning in 2023?

NWS will enhance the information we provide to the existing PCA service level. Details on these improvements are provided at the bottom of this page. For example, based on WFO decisions with local officials and emergency managers, PCA may also be used for NWEMs with this new service level.

How will I know if Partial County Alerting with the new service level begins for a county in 2023?

NWS will issue WFO-specific Service Change Notices. Announcements will be aired on NWR. Details will be provided on your WFO web page with county maps showing the partition boundaries, the SAME location codes to use with SAME-equipped NWR receivers and the complete list of warnings using PCA by the WFO.

What if I wish to continue receiving automated notifications of warnings for my entire county?

The 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.

     

More Information

Clark County, NV information:

Here is a graphical depiction of Partial County Alerting for a notional county:

The NWS's national expansion of PCA for select counties includes the following enhancements:

+1. Additional NWR service improvements

+2. Information improvements for the weather enterprise and alerting authorities

  • supporting emergency managers and civil alerting authorities by expanding PCA to include Non-Weather Emergency Messages (NWEMs) such as the Civil Emergency Message (CEM) and Evacuation Immediate (EVI)
  • documenting PCA in World Meteorological Organization (WMO)-formatted products for weather warnings and NWEMs using a Partition Tag Line located below the double ampersand (&&) symbol.
  • documenting PCA in Common Alerting Protocol version 1.2 (CAP v1.2) messages for weather warnings (Note: The NWS does not disseminate CAP messages for NWEMs.)
  • documenting NWS’ use of PCA in a new AWIPS shapefile PCA database 

 

Feedback method 

Please submit any comments, suggestions or questions to:
Mr. Timothy Schott
301-427-9336 | timothy.schott@noaa.gov