Breakpoints

Used by the National Hurricane Center (NHC), the U.S. National Weather Service (NWS), and emergency managers, breakpoints are predetermined geographical positions along a coastline within which hurricane and tropical storm watches and warnings could, if necessary, be issued. Maintained by the NHC for the Atlantic and Gulf coasts, Cuba, Mexico, and the Bahamas, the use of breakpoints essentially allows the NHC and those organizations responsible for tropical cyclone-related relief operations, to identify a finite section of coastline along which an existing hurricane or tropical storm might come ashore. 

Since there remains considerable variance in forecast models and tropical cyclone activity, it is not always possible to pinpoint where a tropical cyclone will make landfall; the use of breakpoints establishes the boundaries within which this could occur, and thereby permits the activation of more effective evacuations and other emergency preparations. For instance, Cape Lookout, North Carolina, is a breakpoint, while the next to the north is Ocracoke Inlet; after that, Cape Hatteras. Depending on the nature of a representative tropical system and the variances in the guidance envelope, the NHC might choose to set hurricane watches for locations between the Cape Lookout and Ocracoke Inlet breakpoints, and a hurricane warning for the coastline between the Ocracoke Inlet and Cape Hatteras breakpoints. As there are hundreds of breakpoints along the U.S. coastlines, tremendous flexibility in pinpointing breakpoint zones can be achieved.