FEMA has planned a test of the Emergency Alert System and Wireless Emergency Alerts (WEA), which allows the president to send a message to all phones in the US in case of a national emergency. This test was originally scheduled for Thursday September 20, but has been postponed until October 3 due to Hurricane Florence and the ongoing response effort.
This Presidential Alert test will send a message with a loud tone (or vibration if your phone is on silent) at 2:18PM Eastern time on Wednesday October 3. The header of the message will say "Presidential Alert" and the body of the message will read "THIS IS A TEST of the National Wireless Emergency Alert System. No action is needed." The message will come through just like a weather or Amber alert does, except unlike those alerts, users won't have the ability to disable the Wireless Emergency Alerts.