A nationwide emergency alert test is coming to your phone on Wednesday

The first test of the national wireless emergency system by the Federal Emergency Management Agency is shown on a cellular phone in 2018. This year's test will look a lot like this. (Paul Sancya/AP)

Paul Sancya / Paul Sancya

Consider yourself warned. The federal government will conduct a nationwide test of the emergency alert system on Wednesday afternoon.

The test messages will be sent to all cellphones, televisions and radios. The test will emit sound and — on phones — vibration.

The Federal Emergency Management Agency and the Federal Communications Commission are running the test in preparation for actual emergencies. The aim of the test is to ensure the emergency messaging system is running smoothly in the event Americans are threatened by natural disasters, terrorism or other dangers to public safety.