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. National Security Who Should Warn The …NPR - Emma Bowman • 1dRead more on npr.orgSee moreSee more stories in Natural DisastersSee more stories in Emergency Alert SystemSign upSee more stories in News…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. National Security Who Should Warn The …NPR - Emma Bowman • 1dRead more on npr.orgSee moreSee more stories in Natural DisastersSee more stories in Emergency Alert SystemSign upSee more stories in NewsWW…