Specific Area Message Encoding
From The RadioReference Wiki
Specific Area Message Encoding, or SAME, is the technique the National Weather Service to restrict weather watches and other EAS messages to certain geographica areas. Individuals only hear alerts which may have direct impact on them, thus cutting down on unecessary alarms.
There are about 650 NOAA Weather Radio stations around the US and each of these stations covers a radius of about 40 miles. Obviously each one of these stations covers many counties. You may not want to be notified about an event that is taking place on the other side of a station’s coverage area. By using the specific code for your area, you limit when your weather radio sounds alerts to those alerts containing the SAME code you have programmed in to your receiver.
Recently the NWR also started broadcasting other types of Emergency Alert System (EAS) codes, a summary of this action can be found at the National Weather Service web site. The specific area code for your location (in the US or its possessions) can be found at this NOAA site.