You've probably heard the infamous phrase "This is only a test" while listening to the radio or watching TV in the wee hours of the morning. Those alerts are tests of the Emergency Alert System (EAS) conducted at the state and local level, but suprisingly, the system has yet to be tested on a national level. You can expect that to change this coming Wednesday, November 9th at 2PM ET, when the FCC, Department of Homeland Security, FEMA, and National Weather Service will conduct the first nationwide test of the EAS. The trial will be the first test of the Presidential Emergency Action Notification system, which allows the President to communicate with the American public during a national emergency. It will appear on US broadcast radio and TV stations, cable TV, satellite radio, and satellite TV. It won't, however, appear on cellphones despite the earlier, mistaken test by T-Mobile. The 30 second test will look similar to local EAS tests (see an example below).

The EAS replaced the Emergency Broadcast System in 1994, and is frequently used to alert the public about local weather emergencies. November 9th's test will be used to assess the reliability and effectiveness of the EAS on a national scale and see if it needs improvement. So, don't panic when you see or hear the familiar pattern on your TV or radio tomorrow at 2PM ET, it's just a test.