FEMA is conducting its first nationwide Wireless Emergency Alert (WEA) test on Sept. 20 at 12:18 p.m. our time (2:18 p.m. EDT).
This means your cell phone and all cell phones around you should make unusual tones and display an alert message on your home screen.
Be aware that any press conferences or events held at that time will be interrupted.
No action during the test is required on your part. Just pay attention.
For more information click the following links: FEMA Website WEA Test Fact Sheet