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NOAA Weather Radio
NOAA Weather Radio
from Wikipedia

NOAA Weather Radio (NWR), also known as NOAA Weather Radio All Hazards, is an automated 24-hour network of VHF FM weather radio stations in the United States which broadcast weather information directly from a nearby National Weather Service office. Its routine programming cycle includes local or regional weather forecasts, synopsis, climate summaries or zone/lake/coastal waters forecasts, and can be shortened to specifically include hazardous weather outlooks, short-term forecasts, special weather statements or tropical weather summaries during hazardous weather events. It occasionally broadcasts other non-weather related events such as national security statements, natural disaster information, environmental and public safety statements such as Amber alerts, civil emergencies, fires, evacuation orders, and other hazards sourced from the Federal Communications Commission's (FCC) Emergency Alert System. NOAA Weather Radio uses automated broadcast technology that allows for the recycling of segments featured in one broadcast cycle into another and for consistent regular updating of segments to each of the transmitters.

Key Information

Weather radios are widely sold online and in retail stores that specialize in consumer electronics in Canada and the US. They are available in many supermarkets and drugstores in the southern and midwestern US, which are particularly susceptible to severe weather—large portions of these regions are commonly referred to as "Tornado Alley".

NOAA WR-120 EZ Weather Radio
NOAA Radio Station in Robinson, TX (November 23, 2021)

History

[edit]

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.[1][2] Proving to be successful, the broadcasts expanded to serve the general public in coastal regions in the 1960s and early 1970s.[3] By early 1970, ESSA listed 20 U.S. cities using 162.55 MHz and one using 163.275 "ESSA VHF Radio Weather."[4] 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.[1] The service was designed with boaters, fishermen, travelers and more in mind, allowing listeners to quickly receive a "life-saving" weather bulletin from their local weather forecast office (WFO), along with routinely updated forecasts and other climatological data in a condensed format at any time of the day or night. The general public could have the latest weather updates when they needed them, and the benefit of more lead-time to prepare during severe conditions. In 1974, NOAA Weather Radio (NWR), as it was now called, reached about 44 percent of the U.S. population over 66 nationwide transmitters.[3] NWR grew to over 300 stations by the late 1970s.[2]

Local NWS staff were the voices heard on NWR stations from its inception until the late 1990s when "Paul" was introduced.[5][6] 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.[5] "Paul" was a computerized voice using the DECtalk text-to-speech system.[5] "Paul's" voice was dissatisfactory and difficult to understand; thus "Craig", "Tom", "Donna" and later "Javier" were introduced in 2002 using the Speechify text-to-speech system from SpeechWorks (not to be confused with the iOS app of the same name).[5][6] A completely new voice from the VoiceText text-to-speech system, also named "Paul", was introduced in 2016 and implemented nationwide by late in the year. Live human voices are still used occasionally for weekly tests of the Specific Area Message Encoding (SAME) and 1,050 Hz tone alerting systems, station IDs, and in the event of system failure or computer upgrades. They will also be used on some stations for updates on the time and radio frequency.

In the 1990s, the National Weather Service adopted plans to implement SAME technology nationwide; the roll-out moved slowly until 1995, when the U.S. government provided the budget needed to develop the SAME technology across the entire radio network. Nationwide implementation occurred in 1997 when the Federal Communications Commission (FCC) adopted the SAME standard as part of its new Emergency Alert System (EAS).[1] NOAA Weather Radio's public alerting responsibilities expanded from hazardous weather-only events to "all hazards" being broadcast.[7]

Expansion

[edit]

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.[8][4] The service was expanded to coastal locations during the 1970s in the wake of Hurricane Camille based upon recommendations made by the Department of Commerce after the storm in September 1969.[9]

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.[10][11][12][13]

In the 1950s, the Weather Bureau started with KWO35 in New York City and later added KWO39 in Chicago.[8] By 1965 it had added KID77 in Kansas City, home to the Severe Local Storms Center, as the third continuous VHF radio transmitter with the fourth, KBA99 in Honolulu, operating by January 1967.[14][15][16]

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.[17][18] 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.[19][20][21] This grew to over 500 radio stations by May 1999, and over 800 by the end of 2001.[22][1] As of January 2020, there were about 1,032 stations in operation in fifty states, Puerto Rico, the U.S. Virgin Islands, American Samoa, Guam, and Saipan, with over 95% effective coverage.[23]

Operations

[edit]

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

[edit]

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

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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

[edit]

Broadcast schedule

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Local NOAA offices update the content broadcast over NOAA Weather Radio transmitters on a regular basis, according to the following schedule:

Local time Update
01:00–12:00 Area climate summary (played in 15-minute intervals during this period)
04:30 Regional forecast (updated)
05:00–07:00 Regional weather synopsis (updated at least once during this period)
07:00 Hazardous weather outlook and call for action for NWS-trained SKYWARN volunteer weather spotters (if warranted)
07:00 Regional climate summary (recorded sometime between 18:00 the previous night and 07:00 each day)
10:30 Regional forecast (updated)
12:00 Hazardous weather outlook and call for action for NWS-trained SKYWARN volunteer weather spotters (if warranted)
13:00–15:00 Three- to five-day extended forecast (updated twice a day during this period)
15:30 Regional forecast (updated)
16:00–22:00 Regional weather synopsis (updated at least once during this period)
17:00–21:00 Area climate summary (played in 15-minute intervals during specific days of the week)
20:30 Regional forecast (updated)

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

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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.

Segment On-air updates Description
Hourly Weather Roundup :05/:10/:15 past the hour A one- to two-minute segment outlining the current weather conditions for the NWR station's service region, detailing the most recent hourly observation for the main reporting station (consisting of current sky condition, air temperature, dew point, humidity, wind speed/direction and barometric pressure, as well as apparent temperature and gusts when applicable), current observations within 40 miles, then current observations within 80 miles of the WFO's area of responsibility, and finally an abbreviated observation summary for the main reporting station.
If no report is available from the main reporting station, the report from the closest observation site will be substituted. In some locales, if a regularly-reported station has no available report, the message "the report from [city] was not available" will be broadcast. The regional portion may be condensed to a roundup format if the temperatures are within a 5 °F range or if sky conditions are the same or differ limitedly at each given reporting site.
Occasionally, due to technical or other problems, the previous hour's observations segment may be included in the product playlist as long as 15 minutes into the next hour, after which it is removed until updated information is available.
Hazardous Weather Outlook 7:00 a.m. and 12:00 p.m. (if needed) This segment overviews the information about potential thunderstorm activity (including any areas forecast to be under threat of severe thunderstorms), heavy rain or flooding, winter weather, wildfire, extremes of heat or cold, or other conditions that may pose a hazard or threat to travel, life or property over the next seven days. Occasionally, a NWS WFO may update the Hazardous Weather Outlook while an event is ongoing or if forecast models denote changes from previous forecasts. Depending on the NWS office, it may either state all weather hazards from Day 1–7 or Day 1 separately from Day 2–7.
Regional Weather Synopsis/Summary Every 5–6 hours (starting from 3:00 or 5:00 a.m. depending on the station) A report that provides a brief overview of weather events from the previous or current day within the region, followed by an outlook of expected weather from the current time to the next few days.
Regional Climate Summary Every 15 minutes (overnights, mornings and evenings) A summary includes information on the minimum and maximum temperatures recorded the previous day; 30-year temperature averages and historical temperature extremes. It also includes wind speed data, sky cover data, historical humidity extremes, humidity averages, the day's recorded weather conditions and heating with(out) cooling degree day data. Depending on the areas, the sunrise and sunset times for the next two days are stated within the summary or as a separate report.
Some stations broadcast this first report as early as 1:00 a.m. and the last report as late as 12:00 p.m.
Regional Forecast 4:00 a.m. and 3:30 p.m. (more if needed) A report that provides the forecasts for the next seven days for all the counties across the station's coverage area. In case the time for the updates on another segment has not come yet, this forecast will typically be broadcast on a looped format.
Short Term Forecast Randomized times A localized, event-driven report used to provide the public with detailed weather information during significant or rapidly changing weather conditions during the next 3–6 hours. This forecast will often mention the position of precipitation as detected by radar. In most areas, this forecast product is not included during routine programming, but will be included when severe weather threatens the listening area.
Special Weather Statement A regional event-driven report using to provide the public with details of the upcoming significant weather event, such as a major winter storm, a heat wave, or potential flooding. A significant weather advisory may be issued within a Special Weather Statement, often if thunderstorm activity whether severe or not is occurring in, or approaching an area.
Record Information Announcement A segment providing newly set records for coldest/warmest maximum or minimum temperature and maximum precipitation.
Zone Forecast Depending on the office A text forecast for local beaches issued by coastal stations, including coastal hazard information such as that pertaining to rip currents. In more coastal offices, this forecast is scheduled to play every cycle, compared to every half hour in more inland offices.
River Forecast If needed This forecast is only broadcast if there is a potential for flooding or it is occurring, which would then be included with the hazardous weather outlook. Daily river forecasts are issued by the 13 river forecast centers using hydrologic models based on variables such as rainfall, soil characteristics and precipitation forecasts. Some forecasts, especially those in mountainous regions, also provide seasonal snow pack and peak flow forecasts. A separate forecast, River and Small Stream Observations, is broadcast in areas in and outside the 13 river forecast centers and is only broadcast following a significant hydrological event featuring information on crests, and present and forecasted flood stages.
Lake Forecast A forecast that is issued by most stations in the Great Lakes region to explicitly state expected weather conditions within the marine forecast area through the next five days. The report addresses expected wave heights and small-craft advisories currently in effect.
Coastal Waters Forecast A forecast stating expected weather conditions and wave heights within the marine forecast area through the next five days.
Tropical Weather Summary Every three hours (only if needed) An event-driven report provides an information summary on any active tropical cyclones. Activity summaries for the Atlantic Basin are typically included with stations located in states near the Gulf of Mexico, Caribbean Sea and Atlantic Ocean, while stations along the West Coast receive summaries concerning the Pacific Ocean. Depending on the station and associated Weather Forecast Office, listeners can hear this report every half hour.
Ultraviolet Index A daily exposure index played on some NOAA stations. The ultraviolet (UV) index is categorized by the maximum exposure of the sun's rays during the peak hours of sunlight. It ranges in the following numbers/categories:

1-2 (Low), 3-5 (Moderate), 6-7 (High), 8-10 (Very High), and 11+ (Extreme)

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

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Clockwise from top: rack-mountable Gorman-Redlich CRW-S, yellow handheld Sangean DT-400W*, hand-crank BayGen Freeplay, portable Sony ICF-36, and white Midland WR100* base station weather radios
*Public Alert-certified

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[24][25] and was instrumental in the design of the PSK31 Digipan software and hardware,[26] 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.[27]

The price of a consumer-grade weather radio varies depending on the model and its extra features.[28]

Radio frequencies used

[edit]
National Weather Radio frequencies
for U.S., Canada, and Mexico (et al.)
# WX8-WX12 frequency order and inclusion varies
Frequency WX[29]
Channel
Marine
channel
Radio
preset
162.400 MHz WX2 36B 1
162.425 MHz WX4 96B 2
162.450 MHz WX5 37B 3
162.475 MHz WX3 97B 4
162.500 MHz WX6 38B 5
162.525 MHz WX7 98B 6
162.550 MHz WX1 39B 7
161.650 MHz WX8 21B blank
161.750 MHz WX# 23B blank
161.775 MHz WX9 83B blank
162.000 MHz WX# 28B ASM 2
163.275 MHz WX# 113B blank

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).[30][31] Bermuda only uses 162.550 (land) and 162.400 (marine).[32][33]

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.[34] 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.[10][11][12][13]

163.275 MHz was used by KHB47 in New London, Connecticut initially in 1969 until switching to 162.400 in 1970 to avoid overlapping with KWO35 in New York, and internally by NWS in case of power outage, but is no longer in active use.[35][4][10][36] 169.075 MHz was initially used by WWG75 transmitting from Mt. Haleakala on Maui in 1970 before also switching to 162.400 by 1972.[10][37][38]

Channel designations

[edit]

NOAA Weather Radio, Weatheradio Canada and SARMEX all refer to the seven stations by their frequencies (MHz):[39][23][30][31]

162.400 162.425 162.450 162.475 162.500 162.525 162.550

Other channel designations such as WX1 through WX7 "have no special significance but are often designated this way in consumer equipment" and "other channel numbering schemes are also prevalent/possible" according to NOAA and USCG.[29][40] Ordering channels by when they were established (WX1, WX2, ...) is "becoming less 'popular' over time than a numerical ordering of channels."[29] Weather radios may list stations in the order of their WX#, or by a "Preset Channel" number 1 through 7 in ascending frequency order.[41][42][43]

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.[44][45][46] 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.[47]

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.[citation needed]

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.[citation needed]

Present day

[edit]
Public service announcement featuring comic strip character Mark Trail promoting NOAA Weather Radio
Example NOAA weather radio coverage for eastern Michigan

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

[edit]

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.[48] 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.[49] 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.[50]

Alerting

[edit]
Audio from NOAA Weather Radio and the Forest Service Sawtooth Avalanche Center broadcasting of a Backcountry Avalanche Warning issued for Elmore, 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 1,050 Hz attention tone 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 SAME header/data signal 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.[51] 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.[52]

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.[53] 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

[edit]

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:

"This is the National Weather Service office in [city]. The preceding signal was a test of the NOAA Weather Radio warning alarm system on station [call sign of radio station] in [location]. During potential or actual dangerous weather situations, specially built receivers are automatically activated by this signal to warn of the impending hazard. Tests of this signal and receivers' performance are usually conducted by this National Weather Service office on Wednesdays at [time of day]. When there is a threat of severe weather, or existing severe weather is in the area on Wednesday, the test will be postponed until the next available good-weather day. Reception of this broadcast, and especially the warning alarm signal, will vary at any given location. The variability, normally more noticeable at greater distances from the transmitter, will occur even though you are using a good quality receiver in perfect working order. To provide the most consistent warning service possible, the warning alarm will be activated only for selected watches and warnings affecting the following counties: [list of counties]. This concludes the test of the warning alarm system on NOAA Weather Radio station [call sign]. We now return to normal programming."[54]

Or, for other offices which test on Wednesday:

"This is the National Weather Service forecast office in [City, State]. The preceding signal was a test of the public warning alarm system for NOAA All Hazards Radio Station [NWR Transmitter Callsign]. During potentially dangerous weather situations, specially built receivers can be automatically activated by this signal to warn of the impending hazard. Tests of this signal and receivers' performance are normally conducted each Wednesday between the hours of 11 AM and 1 PM. If there is a threat of severe weather the test will be postponed until the next available good-weather day. Reception of this broadcast, and especially the warning alarm, will vary at any given location. The variability, normally noticeable at greater distances from the transmitter, can occur even though you are using a good quality receiver in good working order. To provide the most consistent and dependable warning service possible, the warning alarm will be activated for watches and warnings affecting the following counties: [list of counties]. This concludes the test of NOAA Weather Radio station [NWR Transmitter Callsign]. We now return to the normal broadcast."[55]

Voices

[edit]

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.[56]

System upgrades

[edit]

1990s Console Replacement System

[edit]

To manage the increasing number of transmitters for each office and to speed the overall delivery of warning messages to the public, the Console Replacement System (CRS) was deployed at NWS weather forecast offices in 1997.[56] 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.[5] Although CRS greatly enhanced the delivery speed and scheduling of Weather Radio messages, some listeners disliked Paul's voice, as it was very monotone and did not resemble a normal speaking voice due to CRS not having the technological advances at the time to resemble human speech patterns.[56]

Voice Type of weather message File size
CRS Paul Weather Synopsis 191 KB

2002 Voice Improvement Program

[edit]

In 2002, the National Weather Service contracted with Siemens Information and Communication and SpeechWorks to introduce improved, more natural voices. The Voice Improvement Plan (VIP) was implemented, involving a separate computer processor linked into CRS that fed digitized sound files to the broadcast suite. The improvements involved one male voice ("Craig"), and one female voice ("Donna"). Additional upgrades in 2003 improved "Donna" and introduced an improved male voice nicknamed "Tom", which had variable intonation based on the urgency of the report. As part of this upgrade, a Spanish voice, "Javier", was added at a few sites.[56] Due to the superior quality of the "Tom" voice, most NWS offices used it for the majority of broadcasts and announcements.

Voice Type of weather message File size
VIP Tom Coastal Waters Forecast 481 KB
VIP Tom Local Forecast 498 KB
VIP Tom Weather Synopsis 125 KB
VIP Donna Great Lakes Marine Forecast 220 KB
VIP Donna Hazardous Weather Outlook 127 KB
VIP Donna Hourly Weather Observation 268 KB
VIP Javier Climate Summary 112 KB
VIP Javier Hourly Weather Observation 292 KB
VIP Javier Local Forecast 285 KB

Broadcast Message Handler

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In 2016, the NWS replaced almost all of the CRS systems in operation at its Weather Forecast Offices—which had been in use for over 20 years and were approaching the end of the system's expected service life—with the Broadcast Message Handler (BMH). The new system is more closely integrated with the AWIPS software and intended to be more reliable.[57] The BMH units replaced "Donna" and "Tom" with an improved "Paul" voice (its classification from new voice partner NeoSpeech[58][59]). 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.[60] Many of the stations saw an initial negative reaction primarily due to many mispronunciations.[citation needed] Most local NWS Offices provide a method of reporting these problems, and have the ability to reprogram the voices accordingly.

Voice Type of weather message File size
BMH Paul Local Forecast 280 KB
BMH Violetta Marine Forecast 1,196 KB

Human voices

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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.[citation needed]

Broadcasting in Spanish

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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.[61] 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

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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.[62] 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

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References

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Revisions and contributorsEdit on WikipediaRead on Wikipedia
from Grokipedia
NOAA Weather Radio (NWR), also known as NOAA Weather Radio All Hazards, is a nationwide network of over 1,000 radio stations operated by the (NWS) that broadcasts continuous weather forecasts, warnings, watches, and alerts for non-weather hazards 24 hours a day, seven days a week. The service delivers official NWS information directly from local forecast offices to the public, emergency managers, and , serving as a critical tool for and response across the , its territories, and adjacent waters. Initiated in late 1951 with aviation-focused radio broadcasts from a station in and in early 1952 from a station in , NWR evolved from early Weather Bureau efforts into a dedicated public warning system, expanding significantly in the and to reach 95 percent of the U.S. population through strategic transmitter placements. Transmissions occur on seven very high frequency (VHF) channels in the 162.400 to 162.550 MHz range, with typical reception limited to about 40 miles from each transmitter, though coverage varies by , antenna height, and receiver quality. Key features include voice broadcasts in English and Spanish (in select areas), as well as digital coding via (SAME), which allows compatible receivers to automatically alert users only for events in programmed geographic areas, enhancing targeted notifications for hazards like tornadoes, floods, and chemical emergencies.

History

Origins and Early Development

The U.S. Weather Bureau established the precursor to NOAA Weather Radio in late 1951 as a continuous weather broadcast service, beginning with experimental transmissions on station KWO-35 in . This initiative aimed to provide pilots with real-time meteorological updates via VHF radio frequencies, addressing the growing needs of post-World War II . In 1953, the network expanded with the activation of station KWO-39 in , focusing initial transmitter installations on major urban centers to ensure reliable coverage for aircraft operations. By the early 1960s, the service transitioned toward broader utility, particularly after aviation-specific broadcasts shifted to a dedicated frequency around , allowing existing stations to incorporate content for the general public in coastal regions, including marine forecasts. This shift marked the beginnings of its role beyond aviation, with further impetus from the , which killed 271 people across the Midwest and prompted federal recommendations for a nationwide warning network. In 1966 and 1967, nine additional coastal stations were added to enhance maritime support, introducing the first general public forecasts and solidifying the system's public service orientation under the Weather Bureau's evolving structure. In the early , warnings were integrated into routine broadcasts, enabling rapid dissemination of alerts for tornadoes, floods, and other hazards to improve public safety. Concurrently, early receiver development emerged to make the service accessible, with manufacturers like producing affordable FM tuners capable of picking up the VHF signals by the late and early . This period laid the groundwork for the network's growth into a comprehensive national system following the creation of the in 1970.

Expansion and Network Growth

The expansion of the NOAA Weather Radio (NWR) network accelerated in the 1970s following the devastating Super Outbreak of tornadoes on April 3–4, 1974, which killed 330 people across 13 states and underscored deficiencies in public warning systems. At the time, the network comprised 29 transmitters covering a limited area, primarily coastal and aviation-focused regions. In response, enacted Public Law 93-288, the Disaster Relief Act of 1974, which allocated funds to enhance national disaster preparedness, including radio-based alerts. By late 1974, transmitter count had risen to 66, extending coverage to approximately 44% of the U.S. population. Throughout the late 1970s, the network continued to grow through cooperative efforts with federal agencies, broadcasters, and local governments, reaching over 300 transmitters by the decade's end and prioritizing inland areas vulnerable to . The 1980s saw further development, including the addition of four new VHF frequencies (162.425, 162.450, 162.500, and 162.525 MHz) to reduce interference and support denser placement. By 1985, nearly 400 transmitters were operational, enabling broader dissemination of warnings. That year, the initiated experiments with digital coding technologies, such as (SAME), to target alerts for non-weather hazards like chemical spills and earthquakes, marking the conceptual shift toward an all-hazards system. The brought rapid scaling, driven by heightened awareness of risks, with the network surpassing 386 transmitters by 1994 and covering about 75% of the population. In 1995, Vice President launched a national initiative to achieve 95% population coverage, fostering partnerships with private industry and state entities to accelerate deployments. By the mid-, over 500 transmitters were in place, reaching roughly 90% of the U.S. population. A pivotal integration occurred in 1997 when NWR was incorporated into the newly established (EAS), replacing the and allowing seamless relay of national and local alerts across radio, TV, and cable. Into the 2000s, the network emphasized comprehensive hazard coverage, officially expanding to include warnings in 2002 to bolster coastal resilience following increased Pacific seismic activity. Transmitter growth culminated with the installation of the 1,000th unit in , in 2008, solidifying 95% national population coverage by 2010 and ensuring redundant alerting in remote and high-risk areas. This milestone reflected decades of iterative buildup, transforming NWR from a niche tool into a cornerstone of public safety .

Modernization Efforts

In 2016, the completed the nationwide rollout of the Broadcast Message Handler (BMH) system for NOAA Weather Radio, replacing the aging Console Replacement System (CRS) that had been in use since the late . This integrated NWR broadcasting directly into the Advanced Weather Interactive Processing System (AWIPS), enabling more reliable automation, synthesized voice generation from text products, and seamless handling of emergency alerts across all transmitter sites. The transition improved operational efficiency by reducing manual interventions and enhancing the system's ability to disseminate time-sensitive weather and non-weather hazard information in real time. Despite these advancements, coverage gaps persist in remote and rugged terrains, particularly in parts of and , where topographic challenges limit signal . As of 2025, the network provides approximately 95% U.S. population coverage through 1,035 transmitters, but full continental extension remains incomplete in isolated areas reliant on alternative communication methods. These limitations underscore ongoing challenges in achieving ubiquitous access, especially during events where cellular and services may fail. Recent legislative efforts aim to address these issues through the NOAA Weather Radio Modernization Act (S.2583), reintroduced in August 2025 by Senator . The bill directs the Under Secretary of Commerce for Oceans and Atmosphere to upgrade outdated transmitters, transition to IP-based backhaul and cloud dissemination for greater reliability, and expand coverage to underserved regions, including enhancements for geo-specific alerts. This initiative builds on prior modernization goals to ensure resilient broadcasting amid increasing severe weather frequency. Looking ahead, future enhancements include deeper integration with Next Generation Weather Radar () upgrades, which support faster data processing and alert propagation to NWR for more timely warnings. Additionally, plans explore the deployment of low-power fill-in to bridge remaining gaps in transmitter coverage without requiring full-scale overhauls. These developments, aligned with the National Weather Service's broader transformation strategy through 2025, prioritize scalability and redundancy to bolster public safety.

Operations

Radio Broadcasting System

NOAA Weather Radio operates as a nationwide network of 1,035 automated VHF-FM transmitters managed by the (NWS), providing continuous 24/7 broadcasts of weather information across all 50 states, adjacent coastal waters, , the , and U.S. Pacific territories (as of January 2025). These transmitters vary in output power from low-power units at 5 watts, often used in remote or challenging terrains like , to full-power stations up to 1,000 watts, enabling reliable dissemination of forecasts, warnings, and hazard alerts directly from local NWS forecast offices. The system functions as the primary "voice" of the NWS, ensuring uninterrupted delivery of critical meteorological data to support public safety and emergency preparedness. Signal for NOAA Weather Radio relies on VHF-FM transmission, which is inherently line-of-sight, typically achieving an average coverage radius of up to 40 miles from a transmitter over flat with standard antenna heights. This range can extend to approximately 60 miles when transmitters employ elevated antennas, enhancing signal reach in areas with favorable , while low-power stations may cover only a few miles in urban or obstructed environments. To ensure comprehensive national coverage without gaps, the network incorporates overlapping service areas through operations, where multiple transmitters broadcast identical programming on the same to reinforce signals in transitional zones and mitigate reception issues caused by or atmospheric conditions. The broadcasting system is fully automated, with content generated and sourced from NWS Weather Forecast Offices (WFOs), where routine forecasts, watches, and warnings are prepared and fed into the transmission stream via secure data links. This allows for seamless, cycle-based programming without human intervention at the transmitter level, operating continuously around the clock to maintain accessibility during any time or condition. is built into the infrastructure through backup feeds and mechanisms at WFOs, enabling automatic switching to secondary sources during outages or equipment failures to preserve broadcast continuity and minimize disruptions in service delivery.

Television and Multimedia Integration

The NOAA Weather Wire Service (NWWS), originating in the late and early 1970s as a teletype-based dissemination , provides text and audio feeds of forecasts, watches, warnings, and other hazard information to television and radio broadcasters across the . This service, which evolved from earlier telegraph and wire alert , allows TV stations to receive real-time updates via or for integration into broadcasts, including on-screen text crawls that display critical alerts to viewers during events. Additionally, NWWS serves as a primary method for broadcasters to activate the (EAS), enabling automated interruptions for national or local emergencies. Television-specific adaptations of NOAA Weather Radio (NWR) content focus on enhancing visual media delivery, with local news programs incorporating NWWS feeds into dedicated segments to provide detailed forecasts and updates tailored for on-air presentation. Partnerships between the (NWS) and systems further extend this reach, supporting dedicated channels that continuously display NWR-derived information such as current conditions, radar imagery, and alert summaries on secondary screens or loops. These adaptations emphasize rapid, reliable access to NWS data, fostering collaborations with media outlets to ensure broad public dissemination during routine and emergency situations. Multimedia evolutions in the marked a shift toward diversified formats, including the addition of (fax) broadcast systems for graphical weather products and early email-based bulletins that supplemented traditional wire services for broadcasters and emergency managers. The NWS also funded initiatives, such as the "A.M. Weather" program—a 15-minute daily presentation aired on over 300 Public Broadcasting Service () stations—to deliver NWR-aligned forecasts in a visual, instructional format. In contemporary applications, NOAA's weather content maintains ties to platforms, including integration with national weathercasts available on providers like , where channel 362 features programming that incorporates NWS data for nationwide coverage. Despite these advancements, the integration of NWR with television remains primarily an audio-to-visual conversion , where radio broadcasts are transcribed or summarized into text and graphics for display, rather than originating direct video content from the NWR network itself. This approach leverages the strengths of NWR's continuous audio programming while adapting it for visual media, though it does not involve native video production or streaming from NWR transmitters.

Broadcast Programming

Schedule and Cycle

NOAA Weather Radio maintains a continuous 24/7 broadcast cycle designed for uninterrupted access to essential information, consisting of a repeating four-minute loop that delivers the current forecast, weather synopsis, and relevant regional data such as observations from nearby stations. This cycle is routinely updated every four to six hours, or more frequently during periods of changing conditions to ensure accuracy and timeliness. The structure prioritizes concise delivery, allowing the loop to repeat seamlessly while incorporating any active warnings or advisories as they arise. To enhance regularity, the system incorporates structured hourly routines synchronized to the clock. At the top of the hour (:00) and half-past (:30), a full cycle airs, featuring comprehensive elements like detailed , current , and complete forecast discussions. At quarter-past (:15) and three-quarters past (:45), abbreviated cycles are broadcast, shortening non-critical segments—such as limiting marine forecast details on inland transmitters—to optimize airtime and maintain the overall four-minute pace. These routines ensure listeners receive refreshed core information at predictable intervals without excessive repetition. Daily programming exhibits variations to adapt to time-of-day demands and operational priorities. During nighttime hours, non-essential content like extended climate summaries is typically reduced or excluded, streamlining the cycle to emphasize immediate forecasts and hazards while conserving bandwidth for potential urgent updates. Interruptions occur for live coverage, temporarily suspending the standard loop to broadcast real-time bulletins on threats like storms or floods, after which the cycle resumes. Customization by local National Weather Service offices allows tailoring of the cycle to regional contexts, ensuring relevance; for instance, coastal transmitters integrate more frequent marine forecasts and tidal into the loop, while inland areas prioritize land-based synopses and stages. This localized approach, combined with brief overrides for alerts, maintains the system's focus on life-saving information across diverse geographies.

Content and Routines

NOAA Weather Radio broadcasts follow a structured routine designed to deliver essential and information in a predictable sequence, ensuring listeners receive timely updates without interruption under normal conditions. The core elements of each programming cycle include a regional forecast, a national synopsis, summaries, and any active statements, presented in a fixed order that prioritizes forecasts followed by warnings and advisories. This order allows for comprehensive coverage of local conditions first, such as , , , and sky cover for the served area, before transitioning to broader national overviews and urgent alerts like severe or warnings. , including daily summaries of highs and lows, totals, and heating/cooling degree days, is incorporated 1-3 hours per day, often at specific times like early morning or evening. Specialized routines expand the broadcast to address sector-specific needs, including marine forecasts for coastal and open waters, and fire weather outlooks during high-risk periods. Marine segments typically cover nearshore and offshore conditions, such as wave heights, wind speeds, and small craft advisories, broadcast at intervals like 4 a.m., noon, 4 p.m., and 10 p.m. Fire weather routines focus on dry conditions, wind, and humidity relevant to wildfire-prone regions, integrated into the cycle as needed. Since 2003, non-weather hazards have been included, such as alerts for missing children, chemical spills, and civil emergencies, disseminated via the SAME system to interrupt routine programming when activated by local authorities. Each cycle adheres to a consistent sequence to facilitate easy listening: it begins with the , announcing the call sign, , and coverage area (e.g., "NOAA Weather Radio station KHB-59 serving northeastern "), followed by a precise time check in or . Content blocks then proceed with the core and specialized elements, repeating every 4-6 minutes under normal operations, and conclude with an "end of message" announcement to signal the cycle's completion. Hourly observations, such as current and at local sites, are inserted at :10 past the hour across all cycles. During significant events like hurricanes or severe storms, the routine adapts by shifting to continuous, event-specific updates, suspending non-essential segments such as extended outlooks, climate summaries, or reports to emphasize warnings, safety information, and repetitive advisories. For instance, in hurricane scenarios, programming limits to warnings, evacuation guidance, and impact details, with cycles shortened to ensure frequent repetition. This prioritization maintains the system's role as a primary alert mechanism while preserving .

Receivers and Equipment

Types of Devices

NOAA Weather Radio receivers are available in diverse hardware configurations designed to meet varying user needs, from stationary home monitoring to mobile emergency . These devices are specialized tuners that receive continuous broadcasts on VHF frequencies, providing 24/7 access to weather forecasts, warnings, and hazard information from the . Base-station units, often referred to as desktop models, are intended for fixed installations in homes, offices, or facilities where reliable, continuous reception is essential. These AC-powered devices typically include battery backups for power outages and support external antennas to enhance signal strength in areas with marginal coverage. For example, the Midland WR-120 is a compact desktop radio that scans for alerts specific to user-programmed locations, making it suitable for home use with its wall-mountable design and clear audio output. Handheld and portable receivers cater to users requiring mobility, such as during , outdoor activities, or evacuations, and are powered by rechargeable batteries, solar panels, or hand cranks for operation without grid electricity. These compact units often incorporate additional features like flashlights and phone chargers while maintaining core weather reception capabilities. The Eton FRX3, for instance, is a battery-powered handheld device with hand-turbine charging and NOAA alert functionality, ideal for emergencies where portability is critical. Integrated systems embed NOAA Weather Radio reception into larger platforms, expanding accessibility beyond standalone devices. In vehicles, manufacturers like , Mercedes, , and Saab have incorporated compatible radios into dashboard systems, allowing drivers to monitor broadcasts without additional hardware. For smart home ecosystems, devices such as the integrate weather alerts through voice-activated skills that access NOAA data, while professional setups in schools often use networked base-station models like the Midland WR-120 for centralized alerting across facilities. Many of these integrated options include certified alert features for automated notifications. The evolution of NOAA Weather Radio receivers traces back to the 1970s, when early models were simple analog tuners, such as the "weather cube," permanently fixed to broadcast frequencies for basic reception without advanced features. By the , the adoption of digital encoding like (SAME), which became fully implemented in 1996–1997, enabled more targeted alerts, transitioning receivers toward programmable digital models. Modern devices support multiple channels, improved signal processing, and integration with other technologies, reflecting ongoing advancements in reliability and user customization since the network's formal in 1970.

Alert Features and Certifications

NOAA Weather Radio receivers certified under the Public Alert program must meet specific performance standards to ensure reliable emergency alerting. Established through collaboration between the (NWS) and the (CTA), these standards, outlined in CTA-2009-B (Performance Specification for Public Alert Receivers), require devices to decode the 1050 Hz Warning Alarm Tone (WAT) and automatically activate upon detection of life-threatening alerts. This certification, which began gaining prominence in the early following FCC updates to (EAS) rules in 2002, mandates features such as battery backup to maintain functionality during power outages and visual displays to convey alert details without relying solely on audio. A key component of these certified receivers is (SAME) programming, which allows users to input Federal Information Processing Series (FIPS) codes corresponding to their geographic location for targeted alerts. This enables selective reception of warnings specific to counties or states, filtering out irrelevant broadcasts to reduce alert fatigue. SAME supports a range of event codes, including critical hazards like tornado warnings (TOR) and severe thunderstorm warnings (SVR), among approximately 60 defined EAS events adaptable for NWR use. Beyond core alerting, certified receivers often include user-configurable options such as adjustable alert volumes to accommodate different environments and data ports for integration with systems or external sirens. Some models also facilitate connectivity with EAS receivers, allowing synchronized alerting across broadcast platforms. The NWS endorses only those models bearing the Public Alert logo, which have undergone independent testing and must comply with FCC Part 15 rules to prevent interference and ensure unobtrusive operation.

Technical Infrastructure

Frequencies and Channels

NOAA Weather Radio (NWR) transmits continuous weather broadcasts on seven specific frequencies within the VHF band, spanning 162.400 to 162.550 MHz. These frequencies are designated with channel codes WX1 through WX7, which do not correspond to geographic regions but rather serve as identifiers for receiver tuning and marine radio channel mapping. The channels are as follows:
ChannelFrequency (MHz)
WX1162.550
WX2162.400
WX3162.475
WX4162.425
WX5162.450
WX6162.500
WX7162.525
These assignments originated in the early , when NWR began as experimental broadcasts on the initial of 162.550 MHz (WX1) from stations in and . Additional frequencies were gradually introduced starting in the 1970s to accommodate network expansion, with the full set of seven established by 1980 to support nationwide coverage. The frequencies are allocated at 25 kHz intervals within the dedicated VHF band to prevent interference from or other services, ensuring reliable signal over typical reception ranges. Among them, the WX2 channel at 162.400 MHz is the most prevalent nationwide, utilized by a significant portion of the over 1,000 transmitters to optimize broad-area dissemination without overlap. This spacing and selection align with (FCC) allocations for meteorological aids in the 162 MHz range. All NWR-compatible receivers, including dedicated weather radios, scanners, and multiband devices, must be capable of scanning and locking onto these seven FM-modulated frequencies in the 162 MHz band; standard AM/FM radios cannot tune them without special circuitry. Certification by the ensures devices automatically cycle through the channels to locate the strongest local signal.

Coverage and Transmitter Network

The NOAA Weather Radio (NWR) network comprises 1,032 transmitter sites as of 2020, delivering continuous broadcasts to approximately 95% of the U.S. population across all 50 states, U.S. territories, and adjacent coastal waters. This extensive infrastructure relies on a mix of high-power (typically 300–1,000 watts) and low-power (often 5–10 watts) transmitters, with the latter serving as fillers to extend coverage into rural and remote areas where or distance limits primary signals. Transmitter density varies by region to optimize population and geographic coverage, with more sites in densely populated states such as , which operates 79 stations, compared to sparser networks in expansive areas like , home to 52 primarily low-power sites supplemented by relay systems for isolated communities. Coverage maps generated by the illustrate these patterns, highlighting robust overlap in urban corridors and strategic placement to minimize voids in hazardous-prone zones. While the primary network is U.S.-focused, NWR signals provide limited reception in border regions of and due to the VHF propagation range of approximately 40 miles from transmitters; however, there is no formal international extension or foreign-operated network. Remaining coverage gaps, particularly in urban environments where skyscrapers and other structures cause signal shadowing and interference, are addressed through supplemental and low-power translators that rebroadcast signals to improve penetration in obstructed areas. Ongoing expansions are proposed in the NOAA Weather Radio Modernization Act of 2025 (S.2583), introduced on July 31, 2025, which seeks to authorize investments to upgrade aging infrastructure and enhance nationwide reach, targeting full population coverage by addressing persistent voids in underserved locales.

Emergency Alerting

SAME Technology

Specific Area Message Encoding (SAME) is a digital protocol integrated into NOAA Weather Radio broadcasts to deliver targeted emergency alerts by embedding coded information that specifies the event type, affected geographic areas, and message duration. This technology allows receivers to filter and activate only for relevant alerts, enhancing the efficiency of the all-hazards warning system. SAME was introduced on NOAA Weather Radio with the integration on January 1, 1997, enabling the to transmit precise, location-specific warnings across its network of transmitters. The core of SAME consists of a header code that combines a 6-digit (FIPS) identifier for geographic targeting with a 3-letter event code. The FIPS code uses the first three digits to denote the state (with leading zero, e.g., 039 for ), the next three for the county or equivalent area, and the final digit (typically 0) to indicate full coverage of that jurisdiction; for example, the code 039001 represents all of . This is followed by the event code, such as TOR for a or SVR for a . The full header is transmitted as three short bursts of , audible as static, at the start of each alert transmission. SAME supports 54 distinct event codes (31 weather-related, 17 non-weather, 6 administrative), covering a broad spectrum of hazards including weather-related events like flash flood warnings (FFW) and hurricane watches (HUW), as well as non-weather emergencies such as civil emergency messages (CEM) or required weekly tests (RWT). These codes align with those used in the (EAS), facilitating interoperability. Following the data bursts, a steady 1,050 Hz attention tone sounds for 10 seconds to alert listeners and activate compatible receivers, after which the voice message is broadcast. Receivers programmed with specific FIPS codes decode the header to determine , ignoring unrelated alerts to minimize disruptions. At the conclusion of the message, a brief end-of-message data burst signals the termination. This sequence ensures reliable delivery while allowing for automated filtering based on user-selected locations. By enabling geographic and event-specific targeting, SAME significantly reduces false alarms compared to unfiltered broadcasts, allowing users to receive only pertinent information. Since August 2003, SAME capability has been required for all Public Alert-certified weather radio receivers under regulations, ensuring widespread adoption of this technology. In 2023, the maximum alert duration was extended from 3 hours to 6 hours.

Testing and Activation Procedures

Activation of emergency alerts on NOAA Weather Radio (NWR) is managed by (NWS) offices through either automated or manual processes. Automated activation occurs for weather-related events such as severe thunderstorms, tornadoes, or flash floods when a watch or warning is issued via the NWS's Advanced Weather Interactive Processing System (AWIPS), triggering the alert without human intervention. Manual activation is used for non-meteorological emergencies, including civil danger warnings or national alerts, where NWS personnel input the message directly into the broadcast system. The alert sequence begins with a 1050 Hz attention tone lasting 10 seconds for most warnings, followed by the SAME-encoded header and a voice message detailing the event, typically limited to 5 minutes to ensure timely cycling back to routine programming. In cases of system failure, such as encoder malfunctions or power outages, NWS procedures include fallback options like manual tone generation using backup consoles or direct audio insertion to maintain alert dissemination. Modern NWR operations incorporate digital logging of all broadcasts, including alerts and tests, for post-event verification and compliance reporting, with the NOAA Weather Radio Modernization Act of 2025 proposing enhancements such as automated archival in cloud-based systems for redundancy. Testing protocols ensure the reliability of NWR's alerting capabilities. The Required Weekly Test (RWT), coded as event RWT in the SAME protocol, is broadcast by local NWS offices every Wednesday between 11:00 AM and 12:00 PM local time, simulating an alert with a tone followed by a standard voice message: "This is a test of the National Weather Service NOAA Weather Radio. The preceding signal was a test of this weather radio station's public warning system." This test verifies transmitter functionality, tone activation, and receiver response without audible alarms on many consumer devices to avoid unnecessary disturbances. The Required Monthly Test (RMT), coded as RMT, occurs on the first Wednesday of odd-numbered months (, March, May, July, September, and November) around 8:50 AM local time and fully integrates with the (EAS). During the RMT, NWR simulcasts the test to EAS participants, confirming end-to-end delivery from NWS origination to broadcast relays. Failures in RMT prompt immediate troubleshooting, including manual retransmissions if needed. Since the implementation of the EAS on January 1, 1997, NWR has functioned as the primary entry point for NWS-originated alerts, including national-level messages such as the Emergency Action Notification (EAN) for Presidential addresses. This role positions NWR transmitters as key nodes in the national alerting architecture, relaying SAME-encoded messages to EAS stations via direct feeds or radio monitoring, ensuring rapid dissemination even during widespread disruptions to other communication pathways.

Audio Production

Voice Synthesis Evolution

The evolution of voice synthesis in NOAA Weather Radio broadcasts began in the late 1990s with the deployment of the Console Replacement System (CRS) at (NWS) Weather Forecast Offices. This system automated the generation and delivery of weather messages, replacing manual operations at over 300 sites nationwide. CRS introduced a computerized male voice nicknamed "Paul," powered by the text-to-speech engine developed from research at . The system converted text forecasts into synthesized speech, significantly improving message delivery speed and scheduling efficiency compared to prior human-recorded methods. In the early 2000s, the NWS launched the Voice Improvement Processor (VIP) program to enhance audio naturalness and clarity. Initiated in late and fully implemented by 2002, VIP upgraded the synthesis technology to more human-like voices, replacing "Paul" with "Donna" (female) and initially "Craig" (male), later refined to "Tom" (male) in 2003. These voices were based on the text-to-speech engine from SpeechWorks International, originally derived from Bell Labs' Natural Voices technology, which used concatenated speech segments for smoother intonation and reduced robotic qualities. The upgrades allowed for broader adoption across NWS offices, with "Tom" and "Donna" in use at most sites by late summer 2002. By 2016, the Broadcast Message Handler (BMH) system marked the next major advancement, integrating voice synthesis directly into the Advanced Weather Interactive Processing System (AWIPS) for more robust . BMH replaced the CRS and VIP infrastructures nationwide by the end of 2016, introducing an improved male voice called "Paul" (often referred to as "Paul II" to distinguish it from the original) and a female voice named "Violetta," both provided by NeoSpeech's VoiceText engine. These voices featured enhanced intonation, prosody, and expressiveness to better convey urgency in warnings, while maintaining compatibility with emergency alert protocols. The system supports phonetic adjustments—such as custom s for proper nouns, technical terms, and homographs—to ensure clarity in broadcasts, with text products reviewed for grammatical and pronunciation accuracy before synthesis.

Human and Multilingual Voices

NOAA Weather Radio has historically relied on human voices for its broadcasts, with local National Weather Service staff recording messages on tape cartridges that were played in rotation until the late 1990s. This manual approach ensured regional authenticity but was labor-intensive and limited scalability for 24/7 operations. By the early 2000s, the transition to automated text-to-speech synthesis largely phased out routine human recordings, prioritizing speed and consistency in delivering weather information across the network. Although synthetic voices dominate current programming, human involvement persists in select contexts to enhance clarity and nuance, particularly for station identifications and periodic testing in certain regions where local dialects or pronunciations require manual adjustment. For urgent situations, such as major disasters or evacuation orders, policy emphasizes rapid dissemination via automated systems, but forecasters may intervene to interrupt broadcasts with tailored alerts when synthesis alone cannot convey critical details effectively. Multilingual broadcasting on NOAA Weather Radio focuses primarily on Spanish to serve diverse populations in high-risk areas. Spanish-language service began expanding in the with dedicated transmitters, such as those launched in 2012 for Miami-Dade and Broward counties in and in 2014 for the Rio Grande Valley in , providing continuous Spanish-only cycles of forecasts, warnings, and hazard information. In , the main station WXJ69 in San Juan delivers all programming exclusively in Spanish, covering warnings, watches, and forecasts tailored to local needs. These efforts use synthetic voices like "Violetta," introduced in 2016, to maintain consistent delivery without bilingual segments on primary English channels. Beyond Spanish, NOAA Weather Radio offers no widespread multilingual support. Current prioritizes synthetic voices for efficiency across all languages, reserving human input for message scripting to ensure cultural and contextual accuracy in non-English alerts. In 2025, brief pauses in multilingual alert translations raised equity concerns, but services were reinstated to sustain access for non-English speakers.

Digital Extensions

Internet Streaming

Internet streaming of NOAA Weather Radio (NWR) broadcasts allows users to access continuous weather information and alerts online without dedicated radio hardware. While the (NWS) does not operate a centralized platform, select NWS offices provide downloadable audio files of recent broadcasts. These files capture the same content aired over NWR, including voice announcements and alert tones, but are not real-time streams. There is no official nationwide aggregator for live NWR audio, leaving users to rely on third-party services for broader access. Third-party platforms relay live NWR feeds from various transmitters, enabling internet-based listening through web browsers or apps. For example, offers streams from numerous stations across the U.S., such as those in New York and , though availability depends on the platform's coverage and the specific location's transmitter. Similar services aggregate feeds from volunteer operators and weather enthusiasts, providing options for users outside traditional radio range. These platforms vary in reliability, with some focusing on regional coverage while others aim for national reach. Technically, NWR internet streams are typically encoded at a bitrate of 32 kbps in format, which balances audio quality for voice transmissions without excessive bandwidth use. Alert information is embedded directly in the audio, including SAME tones for emergency activations, though some streams may include basic metadata for track identification. Compared to over-the-air reception, online streams introduce latency of 10 to 30 seconds due to buffering, encoding, and network transmission delays. A key limitation is incomplete coverage: while NWR operates over 1,000 transmitters nationwide, only a —around 147 streams—are available as of November 2025, often depending on volunteer-maintained relays. Access requires a stable public connection, and streams may experience interruptions from server issues or regional outages, making them less suitable for time-critical response than direct radio reception.

Mobile and App Access

Mobile access to NOAA Weather Radio (NWR) content primarily occurs through government-affiliated and third-party smartphone applications that stream live broadcasts or deliver targeted alerts based on NWR data. The FEMA mobile app, developed by the Federal Emergency Management Agency, provides real-time push notifications for severe weather warnings and watches issued by the National Weather Service (NWS), effectively simulating the emergency alerting capabilities of NWR without requiring traditional radio hardware. This app supports up to five user-selected locations nationwide and integrates with the Integrated Public Alert and Warning System (IPAWS) for timely dissemination of NWR-derived hazard information. Third-party applications expand access by offering direct streaming of NWR audio feeds alongside interactive features. For instance, the NOAA Weather Radio app available on both iOS and Android platforms streams over 200 live NWR broadcasts, delivering warnings, forecasts, and hazard updates 24/7 with customizable alerts mimicking Specific Area Message Encoding (SAME) functionality. Similarly, apps such as Clime: NOAA Weather Radar Live incorporate NWR-sourced audio clips within broader radar and forecast tools, enabling users to monitor regional weather conditions on the go. These applications are widely used for their portability, allowing iOS and Android users to replicate the continuous monitoring provided by dedicated NWR receivers. Key features in these mobile integrations enhance usability and reliability for on-the-move users. GPS-based location services automatically detect and alert users to nearby NWR transmissions or relevant hazards, while offline caching allows storage of recent forecasts and alerts for areas with limited connectivity. Integration with smartwatches, such as or devices, supports voice playback of NWR audio segments and vibration alerts, ensuring hands-free access during activities like driving or hiking. Introduced in July and September 2025, the NOAA Weather Radio Modernization Act (S. 2583 and H.R. 5456) aims to expand and modernize the NWR network, including investments in upgrades and standards for emergency communications, particularly in flood-prone areas. As of November 2025, the bills have been referred to committees. These efforts could support broader digital access to NWR information in the future.

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