NOAA Weather Radio

The U.S. Weather Bureau first began broadcasting marine weather information in Chicago and New York City on two VHF radio stations in 1960 as an experiment. Proving to be successful, the broadcasts expanded to serve the general public in coastal regions in the 1960s and early 1970s. By early 1970, ESSA listed 20 U.S. cities using 162.55 MHz and one using 163.275 "ESSA VHF Radio Weather." Later, the U.S. Weather Bureau adopted its current name, National Weather Service (NWS), and was operating 29 VHF-FM weather-radio transmitters under the National Oceanic and Atmospheric Administration (NOAA) which replaced ESSA in 1970. The messages were recorded on tape, and later by digital means, then placed in the broadcast cycle. This technology limited the programming variability and locked it into a repetitive sequential order. It also slowed down the speed of warning messages when severe weather happened, because each NWS office could have up to eight transmitters. Expansion In the wake of the 1965 Palm Sunday tornado outbreak, one of the key recommendations from the U.S. Weather Bureau's storm survey team, was the establishment of a nationwide radio network that could be used to broadcast weather warnings to the general public, hospitals, key institutions, news media, schools, and the public safety community. Starting in 1966, the Environmental Science Services Administration (ESSA) started a nationwide program known as "ESSA VHF Weather Radio Network." In the early 1970s, this was changed to NOAA Weather Radio. Since then, a proliferation of stations have been installed and activated to ensure near-complete geographical coverage and "weather-readiness", many of which have been funded by state emergency management agencies in cooperation with the NOAA to expand the network, or state public broadcasting networks. To avoid interference and allow for more specific area coverage, the number of frequencies in use by multiple stations grew to two with the addition of 162.400 MHz in 1970 followed by the third (162.475) in 1975 with the remaining four (162.425, 162.450, 162.500 & 162.525) coming into use by 1981. In the 1950s, the Weather Bureau started with KWO35 in New York City and later added KWO39 in Chicago. Denver became the 60th NWR station in September 1972 and by December 1976 there were roughly 100 stations transmitting on three channels in December 1976. Growth accelerated in the mid-1970s with NWR reaching 200 radio stations in May 1978 with WXK49 in Memphis, Tennessee; 300 in September 1979 with WXL45 in Columbia, Missouri; and by 1988, the NWS operated about 380 stations covering approximately 90 percent of the nation's population. This grew to over 500 radio stations by May 1999, and over 800 by the end of 2001. ==Operations==

The NOAA Weather Radio network is provided as a public service by the National Oceanic and Atmospheric Administration. NOAA also provides secondary weather information, usually limited to marine storm warnings for sea vessels navigating the Atlantic and Pacific Oceans, to HF band "time stations" WWV and WWVH. These shortwave radio stations continuously broadcast time signals and disseminate the "official" U.S. Government time, and are operated by the Department of Commerce's National Institute of Standards and Technology. Radio The radio service transmits weather and marine forecasts (where applicable) and other related information, without any interruptions. In addition, NWR works in cooperation with the FCC's Emergency Alert System (EAS), providing comprehensive severe weather alerts and civil emergency information. In conjunction with federal, state and local emergency managers and other public officials, NWR has the ability to broadcast alerts and post-event information for all types of hazards, including natural (such as earthquakes or avalanches), human-made (such as chemical releases or oil spills), technological (such as nuclear power plant emergencies) and other public safety (such as "Amber alerts" or 9-1-1 telephone outages). Listening to a NOAA Weather Radio station requires a VHF radio receiver or scanner capable of receiving at least one of seven specific VHF-FM channels within the frequency range of 162.400 through 162.550 MHz, collectively known as the "Weather Band". For example, a receiver that only tunes in standard AM or FM broadcast stations will not suffice. Television Many cable television systems and some commercial television stations will, during EAS activation, rebroadcast the audio of a warning message first heard on their local NWR station, to alert viewers of a severe weather event or civil emergency, usually with the issuance of a tornado warning or tornado emergency, especially in tornado-prone areas of the country. ==Programming==

Broadcast schedule Local NOAA offices update the content broadcast over NOAA Weather Radio transmitters on a regular basis, according to the following schedule: Updates to routine observational products are typically recorded once per hour, and are broadcast at five or 10, and at 15 minutes past the hour. Broadcast routine As a continuous spoken weather service, NOAA Weather Radio All Hazards maintains a multi-tier concept for relaying meteorological observations, routine forecasts and weather hazards to the general public. Actual forecasts and offered products vary by the area serviced by the transmitter. During severe weather situations, Watch Information Statements for government-designated jurisdictions served by the local NWR station are typically inserted within the station's normal playlist of routine products; a special severe weather playlist temporarily suspends most regularly scheduled routine products in the event National Weather Service-issued warnings (mainly severe thunderstorm, tornado or flash flood warnings) are in effect for the station's broadcast area, which solely incorporate watch, warning and Special Weather Statements, and any active Short-Term Forecasts and Hazardous Weather Outlooks. These are additional products that are included in the broadcast cycle occasionally (but are broadcast at randomized times, depending on the individual transmitter[s]): • Air Quality Index Statement • Agricultural Forecast • Area Forecast Discussion • Area Weather Update • Daily/Monthly Hydrometeorological Products • Heat Index Forecast • High Seas Forecast • Hydro-Met Data Report • Miscellaneous Hydrologic Data • Miscellaneous Local Product • Miscellaneous River Product • Public Information Statement • Offshore Forecast • Quantitative Precipitation Forecast • State Forecast • Suppression Forecast • Tabular State Forecast • Terminal Aerodrome Forecast • Travellers Forecast == Weather radio receivers ==

There are a variety of different types of weather radio receivers available in the U.S., including: • Professional-grade receivers, typically rack-mounted, for use by broadcast radio and television stations and public agencies who are responsible for acting on or retransmitting weather and emergency alert broadcasts. • Base-station consumer radios powered by commercial AC power (often with a battery backup). • Hand-held battery powered radios, suitable for use by hikers, boaters, and in emergency preparedness kits. • Hand-crank portable radios that do not require AC or battery power, especially designed for use in emergency preparedness kits. • Weather radio receivers integrated as an auxiliary function into other devices, such as GMRS radios, portable televisions, FM radios, etc. • Radio receiver modules, such as the Si4707 from Silicon Labs, designed for electronics experimenters and project builders have in the past been available. Historically, it was not uncommon to sell portable radios that featured AM, FM, and TV audio (VHF channels 2–13), with the weather band included some distance down the dial from TV channel 7 (after the U.S. digital TV conversion, the television sound function of these radios became obsolete). One of the early consumer weather alert radios (model KH6TY) was designed and manufactured by Howard (Skip) Teller, who was issued a patent on the alerting mechanism and was instrumental in the design of the PSK31 Digipan software and hardware, and the Amateur radio NBEMS emergency communications system. Since April 2004, radio models marketed as "Public Alert-certified" must include these features and meet certain performance criteria, as specified in electronics industry standard CEA-2009. The price of a consumer-grade weather radio varies depending on the model and its extra features. ==Radio frequencies used==

The United States' NWS, Canada's Weatheradio, Mexico's SARMEX and Bermuda operate their government weather radio stations on the same marine VHF radio band, using FM transmitters, and the same seven frequencies (162.400 – 162.550 MHz) as NOAA Weather Radio (NWR). Bermuda only uses 162.550 (land) and 162.400 (marine). NWR transmitters operate VHF-FM between 5–1,000 watts. NWR channels operating in the range of 162.3625–162.5875 MHz (162.4–.55 ± 37.5 kHz) have a band spacing of 25 kHz and may have bandwidths up to 16 kHz. The original "weather" frequency used by multiple stations was 162.550 MHz, followed by 162.400 in 1970, 162.475 in 1975, and the last four (162.425, 162.450, 162.500 & 162.525 MHz) in 1981. 169.075 MHz was initially used by WWG75 transmitting from Mt. Haleakala on Maui in 1970 before also switching to 162.400 by 1972. Ordering channels by when they were established (WX1, WX2, ...) is "becoming less 'popular' over time than a numerical ordering of channels." The "WX#" format is continued from WX8 up to WX12 on some lists and radios to include 163.275 MHz and or one or more of the Canadian continuous marine broadcast (CMB) frequencies 161.650, 161.775, 161.750, 162.000. Unlike WX1-WX7 typically ordered by frequency adoption by NWS, there is no consistent frequency inclusion nor assignment for WX8-WX12. Effective January 1, 2019, channels 2027 (161.950 MHz, 27B) and 2028 (162.000 MHz, 28B) are designated as ASM 1 and ASM 2 respectively for application specific messages (ASM) as described in Recommendation ITU-R M.2092. The "WX" arose from the Morse code prosign shorthand for weather reports (WX) combined with the order number that the seven frequencies were adopted for use nationally. More frequencies helped prevent interference from other nearby transmitters, growing in use in the 1990s in less populated rural areas and as fill-in broadcast translators relaying an existing station or sending a separate, more localized broadcast into remote or mountainous areas, or those areas with reception trouble. As with conventional broadcast television and radio signals, it may be possible to receive more than one of the seven weather channels at a given location, dependent on factors such as the location, transmitter power, range and designated coverage area of each station. The NWS suggests that users determine which frequency (as opposed to channel) is intended for their specific location so that they are assured of receiving correct and timely information. Present day promoting NOAA Weather Radio All seven NWR channels are available on stand-alone weather radio receivers that are sold online and in retail stores (available for prices ranging from US$20 and up), as well as on most marine VHF radio transceivers, amateur radios and digital scanners. In addition, more mainstream consumer electronics, such as clock radios, portable multi-band receivers and two-way radios (such as FRS, GMRS and CB radio), now feature the ability to also receive NWR channels. Many of the aforementioned devices also incorporate automatic alerting capabilities. Many American television stations offer discounted pricing for radios to viewers as a public courtesy (especially in highly tornado-prone areas), where they are often marketed as an essential safety device on par with a smoke alarm for home fires. Coverage According to NOAA, reliable signal reception typically extends in about 40 miles radius from a full-power (1,000 W) transmitter, depending on level terrain. However, signal blockages can occur, especially in mountainous areas. As of 2016, there are over a thousand NWR transmitters across the U.S., covering 95% of the population. Because each transmitter can cover several counties, typically a person will program their weather radio to receive only the alerts for their county or nearby surrounding counties where weather systems are most likely to move in from. ==Alerting==

, Boise, and Valley, Idaho on January 11, 2024. Weather Radio stations will carry alerts when dangerous weather threatens a location within their listening area. Whenever a weather or civil emergency alert is issued for any part of a NWR station's coverage area, many radios with an alert feature will sound an alarm or turn on upon detection of a that sounds just before the voice portion of an alert message. The specification calls for the NWS transmitter to sound the alert tone for ten seconds and for the receiver to react to it within five seconds. This system simply triggers the alarm or turns on the radio of every muted receiver within reception range of that NWR station (in other words, any receiver located anywhere within the transmitter's broadcast area). Generally, receivers with this functionality are either older or basic models. Many newer or more sophisticated alerting receivers can detect, decode and react to a digital signal called Specific Area Message Encoding (SAME), which allows users to program their radios to receive alerts only for specific geographical areas of interest and concern, rather than for an entire broadcast area. These advanced models may also have colored LED status lights which indicate the level of the alert as an "advisory"/"statement", "watch" or "warning" (either amber or green for advisories and statements, orange or yellow for watches, red for warnings). When an alert is transmitted, the is broadcast first (heard as three repeated audio "bursts"), followed by the 1,050 Hz attention tone, then the voice message, then the end-of-message (EOM) data signal (repeated quickly three times). This encoding/decoding technology has the advantage of avoiding "false alarms" triggered by the 1,050 Hz tone itself in locations outside the intended warning area. Broadcast areas are generally divided into SAME locations by county or marine zone using the standard U.S. Government FIPS county codes. NOAA's SAME alert protocol was later adopted and put into use by the Emergency Alert System (EAS) in 1997 – the replacement for the earlier Emergency Broadcast System (EBS) and even earlier CONELRAD – now required by the FCC for standard broadcast TV and radio stations. Environment Canada eventually integrated SAME alerting capability into its Weatheradio Canada network in 2004. Organizations are able to disseminate and coordinate emergency alerts and warning messages through NOAA Weather Radio and other public systems by means of the Integrated Public Alert and Warning System. In September 2008, Walgreens announced that it would utilize SAME technology to deliver local weather alerts via a system of LED billboards located outside its drugstore locations to provide an additional avenue of weather information. Many national billboard companies (such as Outfront Media, Clear Channel Outdoor and Lamar, among others) also use their color LED billboard networks to display weather warnings to drivers, while state-owned freeway notification boards, which utilize the EAS/NOAA infrastructure for Amber alerts, also display weather warnings. ==Emergency alert test procedure==

Every local National Weather Service weather forecast office is required to conduct a scheduled weekly test of the NOAA Weather Radio public alert system, generally occurring every Wednesday between 10:00 a.m. and 12:00 p.m. (noon). Certain Weather Forecast Offices conduct this twice a week, usually testing two time on Wednesday, usually between 10:00 a.m. and 12:00 p.m. (noon) and then again between 6:00 p.m. and 8:00 p.m. Other offices test once on Wednesday, and then again on Saturday. Some NOAA Weather Radio stations also broadcast tests of the Emergency Alert System on predetermined days and times. If there is a threat of severe weather that day in a NWR station's listening area, the weekly test is postponed until the next available fair-weather day (sometimes, a short message stating the reason for the test's cancellation is broadcast). The required weekly test (SAME event code "RWT") interrupts regular NWR programming — during the test, a SAME data header is sent, followed by a 1050 Hz attention tone, the voice test message, then a SAME end-of-message (EOM) signal. The text of the test message used by most NWS offices, with variations depending on the office, is typically as follows: Or, for other offices which test on Wednesday: ==Voices==

From the introduction of NOAA Weather Radio until the late 1990s, nearly all the voices heard in the broadcasts were those of the staff at local National Weather Service (NWS) offices. The messages were manually recorded, first on tape cartridges and later digitally, and then placed in the broadcast cycle. As the NWS added more transmitters to provide broader radio coverage, the staff had difficulty keeping broadcast cycles updated in a timely fashion, especially during major severe weather outbreaks. CRS introduced a computerized voice nicknamed "Paul", using a text-to-speech system which was based on the DECtalk technology. This system was chosen over more readily available concatenative synthesis because each forecast, watch and warning requires unique wording to relay the most accurate and relevant information. Concatenation is typically used by telephone companies, banks and other service businesses where a limited vocabulary of recorded words can easily take the place of specific, repetitive phrases and sentences. NOAA Weather Radio broadcasts contain a wide variety of information which changes with the weather. Forecasters need to have many words to choose from when writing their forecasts and warnings for the public. The BMH units replaced "Donna" and "Tom" with an improved "Paul" voice (its classification from new voice partner NeoSpeech). Many stations have dubbed him "Paul II" or "Paul Jr" to avoid confusion with CRS "Perfect Paul". For the NWS offices that incorporate Spanish programming into the NWR broadcast cycle, VIP "Javier" was replaced with a much improved female voice named "Violetta" (another voice from NeoSpeech). The upgrade initially began at six offices: Greenville-Spartanburg, South Carolina; Brownsville, Texas; Omaha, Nebraska; Portland, Oregon; Anchorage, Alaska; and Tiyan, Guam. Many of the stations saw an initial negative reaction primarily due to many mispronunciations. Most local NWS Offices provide a method of reporting these problems, and have the ability to reprogram the voices accordingly. Human voices Human voices are still heard on occasion, but sparingly, mainly during station identifications, public forecasts, National Marine Fisheries Service messages, public information statements, public service announcements, required weekly tests, and severe weather events. The capability exists for a meteorologist to broadcast live on any transmitter if computer problems occur or added emphasis is desired, or to notify listeners who are concerned about a silent station on another frequency whether that station is dark due to technical errors, prolonged power outage, or a weather event has forced it off the air. Broadcasting in Spanish Some weather forecast offices will issue a secondary report in Spanish during severe weather events or warnings. Few NWR stations broadcast weather information in Spanish. Four offices use dedicated stations which broadcast in the Spanish language, separate from their corresponding English-language channels: San Diego (WNG712 in Coachella/Riverside), El Paso (WNG652), Miami (WZ2531 in Hialeah, since 2012), and Brownsville (WZ2541 in Pharr and WZ2542 in Harlingen, since 2014). These stations originally used a synthesized Spanish male voice named "Javier" for all broadcasts, but have since been upgraded with the BMH female voice "Violetta". The Albuquerque WFO often repeats weather alerts in Spanish after their initial dissemination in English. Station WXJ69 in San Juan, Puerto Rico broadcasts all information, including forecasts, in the same manner. ==Live streaming==

Several websites provide internet audio streaming of a subset of the NOAA Weather radio stations. The most prominent of these, the Wunderadio section of weather information website Weather Underground, discontinued live streams of NWR broadcasts in April 2017. As the Wunderadio internet streaming service dissolved, many other sources developed, allowing previous users of the service to continue monitoring live streams from Wunderadio, as well as newer broadcasts from different locations. ==See also==