 Many NWS offices do not use significant weather advisories, instead issue normal special weather statements mentioning much of the same text used in such an advisory.If severe weather is detected, alerts (mainly a severe thunderstorm or tornado warning) are issued by the National Weather Service (effectively replacing a significant weather advisory), and the Emergency Alert System may activate and broadcast the alert.EAS alerts begin with a SAME header, which sounds as three digital bursts and automatically activates the EAS, a , the alert as processed by text-to-speech software, then the SAME End of Message tone to end the alert broadcast.