At approximately 2:20PM ET, FEMA will conduct a test of both the Emergency Alert System (EAS) and the Wireless Emergency Alerts (WEA) covering radio, TV broadcasts, and mobile devices in the US, but you might not see it on your phone. That’s because this time around, unlike the Presidential Alert test in 2018, it will only reach phones with a setting to receive test messages and by default, most phones are set to opt-out.
According to this document (PDF) from the FCC, on Android phones, there should be a Wireless Emergency Alerts section in your settings menu with an option for “State/Local Test alerts” that you can turn on or off. The process described for iOS is more complicated, but Apple’s support page explains how you can opt-in:
Open the Phone app and tap Keypad.
To turn it on: Enter *5005*25371# and tap . You’ll get an alert that says “Test alerts enabled.”
To turn it off: Enter *5005*25370# and tap . You’ll get an alert that says “Test alerts disabled.”
This year’s Wireless Emergency Alert (WEA) test messages will only be displayed on wireless handsets where subscribers have “opted-in” to receive them. This will allow for a nationwide test without disturbing the public.
— National Weather Service (@NWS) August 9, 2021