For decades, county borders have been used to delineate the coverage of National Weather Service short-fuse convective warnings. With the advancement of technology, it is now possible to issue warnings for areas smaller than a county or for areas that cross county boundaries. Issued by latitude and longitude points, these sub-county ‘polygon’ warnings provide additional information that can be easily ingested by GIS applications. This polygon information has been included with NWS warnings for several years, but until now the polygon data has not been exploited by the agency.

The advantages to GIS users are greater than simply providing more detailed warning information. Such a step forward brings an added ability to query the types of structures and demographic information impacted by the warning. This enables emergency management and other disaster response agencies to use the current warning polygons with other GIS shapefiles to make rapid life and property decisions and improve vital recovery operations.

This step forward is, however, associated with a large number of issues which require a well-coordinated plan for proper resolution and timely implementation. These issues include rewriting performance standards, or verification, of warnings, and dissemination concerns --- how to get the polygon warnings out to the largest number of people in the most effective manner.

A diverse National Weather Service team was established to discuss these issues and recommend solutions as the Agency evaluates the feasibility of advancing to a polygon warning approach. The concept of polygon warnings, the advantages and issues associated with this approach, and the team's initial recommendations regarding a path to polygon warnings will be presented.