From the USA.gov Blog:
Get Weather Emergency Alerts On the Go:
The National Oceanic and Atmospheric Administration (NOAA) is soon launching weather emergency alerts to your mobile devices. Wireless Emergency Alerts (WEA) are emergency messages sent by authorized government authorities through your mobile carrier.
Government partners include local and state public safety agencies, FEMA, the Federal Communications Commission, the Department of Homeland Security, and the National Weather Service.
You will be able to sign up for weather-related emergency alerts through your mobile carrier. The alerts will include extreme weather warnings, local emergencies requiring evacuation or immediate action, AMBER alerts and Presidential alerts during a national emergency. The alerts will look like a text message, but will include a special tone and vibration, both repeated twice.
You can also receive alerts based on your phone’s current location. While most older phones are not WEA-capable, new mobile devices are. For information about which mobile devices are WEA-capable, please visit http://www.ctia.org/wea or contact your wireless carrier.
Learn more about Weather Emergency Alerts.