The first nationwide test of the Emergency Alert System will incorporate all commercial broadcast entities, but will not utilize NWS weather radio stations. The test is expected to take 30-60 seconds to complete. This is the first time that a nationwide activation of the Emergency Alert System has been attempted. Broadcasters are required to conduct weekly and monthly tests of the system.
The message that viewers see during the test may differ from weekly or monthly required tests. The reason for this is that in order for a nationwide alert to take place, a live EAN or Emergency Action Notification will be issued. This is the same activation message that would be issued in an actual emergency.
This test will likely be the first of annual national tests. These tests are being conducted with the goal of improving emergency information communication abilities of federal, state, and local emergency managers. The Emergency Alert System, nor it predecessor, the Emergency Broadcast System have ever been activated on a national scale. This test will allow a critical proof-of-concept confirmation that in dire emergency situations, the President of the United States will be able to convey important information to the entire US public.
Further information on the Emergency Alert System, and the tests being conducted can be found here: FEMA IPAWS EAS Nationwide Test