NWS forecast zone "Garrett County MD" will be split on March 18th

Overview:

In addition to county-based FIPS codes, the NWS maintains forecast/warning zones for some forecast products, and many (although not all) watches/warnings/advisories. 

In order to provide more refinement to watch, warning, and advisory services for Garrett County in western MD, the NWS forecast zone for Garrett is slated to be split in two - an eastern and a western half.

This will be implemented on Tuesday March 18th. 

The current NWS forecast zone 

MDZ001: Garrett County

will be split and given the new zone codes:
 

MDZ509: Western Garrett

MDZ510: Eastern Garrett

Note: This does not impact the county/FIPS code for Garrett County MD, which remains MDC023/ 24023. FIPS codes are what are used by NOAA Weather Radio, so no updates are needed for NOAA Weather Radio.

Rationale: 

These changes will allow the NWS to provide more refinement to watches, warnings, and advisories. This will be most frequent in winter and high wind events, where there can be quite a difference in impacts between the eastern versus the western portions of the county.  Garrett County MD will be converted into 2 separate zones.  This will allow the NWS to refine where weather hazards are located given conditions that can vary significantly between the higher elevations in the western and central parts of Garrett County MD, from the eastern parts of the county. 

Maps:                                                                                                                                                           

 Impacts to the public:

Other than more precise watches, warnings, and advisories for Garrett County, most of the impact from this change will be to automated processing systems that look for NWS zone codes when disseminating our products.  

There will be mostly no change to NOAA Weather Radio (NWR) services in the area. The alerting feature of NOAA Weather Radio uses county codes, not NWS zone codes. So no changes to the code(s) you have programmed into your NOAA Weather Radio are necessary. Three NWR transmitters will continue to serve Garrett County - Frostburg MD, Greggs Knob WV, and Backbone Mountain WV.