On Wednesday, November 9 at 2 p.m. (Eastern Standard Time), FEMA and the Federal Communications Commission (FCC) will conduct the nation's first ever Emergency Alert System (EAS) test. The purpose of this test is to help determine if the national-level system will work as designed, should officials ever need to send a national alert.
This test will last approximately three minutes and will be seen on all local, cable, and satellite TV stations across the country, as well as radio.
For additional information:
http://www.fema.gov/emergency/ipaws/eas_info.shtm
http://www.fcc.gov/encyclopedia/emergency-alert-system-nationwide-test