National Weather Service United States Department of Commerce

Public Comment Period through March 1, 2022: Proposed national expansion of Partial County Alerting for NOAA Weather Radio All Hazards (NWR) and the Emergency Alert System (EAS)

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 can easily select a unique, six digit location code for their local area and receive automated notifications of WFO-issued warnings disseminated with SAME.

The operational implementation of PCA is an opt-in service for those who wish to receive warnings more applicable to their local area. When PCA is implemented for a county, 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. Broadcasters wishing to receive all alerts for their county should check with their equipment manufacturer for a minor setting update.

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:

+1. Expansion of this capability to other WFOs for select counties with the following NWR service enhancements

+2. Expansion of the capability for optional EAS implementation by broadcasters

+3. Enhancements 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
Meteorologist
National Weather Service Headquarters
1325 East-West Highway, Station 14440
Silver Spring, Maryland 20910

Email: Timothy.Schott@noaa.gov