How a NOAA Weather Radio Warning is Disseminated
Your local National Weather Service (NWS) Office uses available data sources such as Doppler Radar, Satellite Imagery, Surface Reports, and Spotter Reports to monitor hazardous weather.
If the threat of a tornado, severe thunderstorm, or flash flood is sufficiently high, then a warning is issued.
The first method of dissemination, normally, is to broadcast live on the NOAA Weather Radio (NWR). If the warning is within the "official" NWR broadcast range (about 40 miles), a 1050 Hertz alarm tone precedes the warning. This 1050 Hertz alarm tone automatically activates NWR receivers equipped with the alert feature. The alarm tone last about 9 seconds, and allows people to deactivate their alarm and listen to the warning broadcast. The NWR is also able to integrate into the Emergency Alert System (EAS), using the Specific Area Message Encoder (SAME). The EAS is activated for life-threatening weather events in specific areas, and incorporates all radio, TV and cable stations. The weather threat is quickly disseminated on these commercial TV and radio stations, reaching a wide audience in the affected area(s).
As the warning is being disseminated on the NWR and EAS, the "hardcopy" of the warning is being generated using computer software. Menu-driven software allows the meteorologists to quickly select the type of warning needed, the valid time of the warning, and the counties that must be warned. Information such as affected areas or communities, timing of severe weather, and a safety message is included in this warning.
Once this "hardcopy" warning is generated, it is sent, via satellite uplink, to a wide variety of customers, including the NOAA Weather Wire Service, Internet, The Weather Channel, and to major news wire services, such as AP, UPI, etc. These services distribute the warning to their customers, which include many local TV and radio stations. The local radio and TV stations then disseminate the warning to their listening and viewing audience.
Emergency Managers enact their local severe weather plans, such as activating local dissemination systems, positioning storm spotters, or activating outdoor sirens, as needed.
Updated information on the storm position and spotter reports is provided in follow-up severe weather statements and broadcast on the NWR as it becomes available.
Listen to NOAA Weather Radio for the most timely and complete warning services!