 | |
| Agency overview | |
|---|---|
| Formed | February 9, 1870; 155 years ago (1870-02-09) |
| Preceding agencies |
|
| Jurisdiction | United States federal government |
| Headquarters | Silver Spring, Maryland 38°59′30″N77°01′48″W / 38.99167°N 77.03000°W /38.99167; -77.03000 |
| Employees | 4,900[1] |
| Annual budget | US$1.364 billion (FY 2023) |
| Agency executives |
|
| Parent agency | National Oceanic and Atmospheric Administration |
| Key documents | |
| Website | weather.gov |
| Footnotes | |
| [5][6][7][8] | |
TheNational Weather Service (NWS) is anagency of theUnited States federal government that is tasked with providing weather forecasts, warnings of hazardous weather, and other weather-related products to organizations and the public for the purposes of protection, safety, and general information. It is a part of theNational Oceanic and Atmospheric Administration (NOAA) branch of theDepartment of Commerce, and is headquartered inSilver Spring, Maryland, within theWashington metropolitan area.[9][10] The agency was known as theUnited States Weather Bureau from 1891 until it adopted its current name in 1970.[11]
The NWS performs its primary task through a collection of national and regional centers, and 122 localWeather Forecast Offices (WFOs). As the NWS is an agency of the U.S. federal government, most of its products are in thepublic domain and available free of charge.
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Early attempts to record weather information can be traced back toJoseph Henry of theSmithsonian Institution, who, after a tornado in Jefferson, Illinois (modern-dayDes Plaines, Illinois) in 1855, wrote to theDaily Democratic Press in Chicago for more information about the storm. Organized large-scale weather recording by the Smithsonian led to the creation of the U.S. Signal Service, the earliest predecessor of the modern-day National Weather Service.[12] In 1869,Cleveland Abbe, then director of theCincinnati Observatory, began developing and issuing public weather forecasts (which he called "probabilities") using daily weather observations collected simultaneously and sent via telegraph by a network of observers. This effort was undertaken in cooperation with theCincinnati Chamber of Commerce andWestern Union, which he convinced to back the collection of such information. Meanwhile,Increase A. Lapham of Wisconsin lobbiedCongress to create a storm warning service, having witnessed the destructive power of storms in theGreat Lakes region.[13] RepresentativeHalbert E. Paine introduced a bill authorizing the secretary of war to establish such a service. On February 9, 1870, the first official weather service of the United States was established through ajoint resolution of Congress signed by PresidentUlysses S. Grant[14] with a mission to "provide for taking meteorological observations at the military stations in the interior of the continent and at other points in the States and Territories... and for giving notice on the northern(Great) Lakes and on the seacoast by magnetictelegraph and marine signals, of the approach and force of storms." The agency was placed under thesecretary of war as Congress felt "military discipline would probably secure the greatest promptness, regularity, and accuracy in the required observations."[15] Within theDepartment of War, it was assigned to theU.S. Army Signal Service under thechief signal officer, Brigadier GeneralAlbert J. Myer. Myer gave the National Weather Service its first name: The Division of Telegrams and Reports for the Benefit of Commerce.[16]
In November 1870, Myer hired Lapham as the first civilian assistant to the new service, but Lapham left less than two years later. Abbe joined as the second civilian assistant to Myer in January 1871 and began developing a system for national forecasts, based on his work in Cincinnati, which he began issuing the following month.[17] Throughout his career with the weather service, which lasted 45 years, Abbe urged continued research inmeteorology to provide a scientific basis for forecasting.[18] While a debate went on between the Signal Service and Congress over whether the forecasting of weather conditions should be handled by civilian agencies or the Signal Service's existing forecast office, a Congressional committee was formed to oversee the matter, recommending that the office's operations be transferred to the Department of War following a two-year investigation.[19]
The agency first became a civilian enterprise in 1891, when it became part of theDepartment of Agriculture and its name officially became the U.S. Weather Bureau. Under the oversight of that branch, the Bureau began issuing flood warnings and fire weather forecasts, and issued the first daily national surface weather maps; it also established a network to distribute warnings fortropical cyclones as well as a data exchange service that relayed European weather analysis to the Bureau and vice versa.[20]
The first Weather Bureauradiosonde was launched inMassachusetts in 1937, which prompted a switch from routine aircraft observation to radiosondes within two years. The Bureau prohibited the word "tornado" from being used in any of its weather products out of concern for inciting panic (a move contradicted in its intentions by the high death tolls in past tornado outbreaks due to the lack of advanced warning) until 1938, when it began disseminating tornado warnings exclusively toemergency management personnel.[21]
The Bureau would in 1940 be moved to theDepartment of Commerce.[22] In 1941, Margaret Smagorinsky (née Knoepfel) was hired as the Weather Bureau's first female statistician.[23][24] On July 12, 1950, Bureau chiefFrancis W. Reichelderfer officially lifted the agency's ban on public tornado alerts in a Circular Letter, noting to all first order stations that "Weather Bureau employees should avoid statements that can be interpreted as a negation of the Bureau's willingness or ability to make tornado forecasts", and that a "good probability of verification" exist when issuing such forecasts due to the difficulty in accurately predicting tornadic activity.[25] After facing criticism for continuing to refuse to provide public tornado warnings and preventing the release of theUSAF Severe Weather Warning Center's tornado forecasts (pioneered in 1948 by Air Force Capt.Robert C. Miller and Major Ernest Fawbush) beyond military personnel, the Bureau issued its first experimental public tornado forecasts in March 1952.[21] In 1957, the Bureau began usingradars for short-term forecasting of local storms and hydrological events, using modified versions of those used byNavy aircraft to create theWSR-57 (WeatherSurveillanceRadar, 1957), with a network of WSR systems being deployed nationwide through the early 1960s;[26] some of the radars were upgraded toWSR-74 models beginning in 1974.[27]
In August 1966, the Weather Bureau became part of theEnvironmental Science Services Administration when that agency was formed. The Environmental Science Services Administration was renamed theNational Oceanic and Atmospheric Administration (NOAA) on October 1, 1970, with the enactment of theNational Environmental Policy Act. At this time, the Weather Bureau became the National Weather Service.[14] At the beginning of the 1980s the NWS used the same radar equipment as in the 1950s, andteletype for communication. In 1983, NOAA administratorJohn V. Byrne proposed to auction off all of the weather satellites, to repurchase data from private buyers, outsourcing weather observation stations, NOAA Weather Radio and computerized surface analysis to private companies but the proposal failed in a Congressional vote.[28]
NEXRAD (Next Generation Radar), a system ofDoppler radars deployed to improve the detection and warning time of severe local storms, replaced the WSR-57 and WSR-74 systems between 1988 and 1997.[29][30]
In 2025, the National Weather Service was deeply affected by cuts toNOAA under the second presidency of Donald Trump, includingstaff being laid off, contracts with universities being cancelled, and restrictions on exchanges with other national weather services.[31][32][33][34][35] Enteringhurricane season, 30 National Weather Service offices were without a chief meteorologist, in part due to Trump administration layoffs.[36]
On August 28, 2025, President Trump signed an executive order, which dissolved the NWS Employee Union, and determined the National Weather Service "to have as a primary function intelligence, counterintelligence, investigative, or national security work". The White House justified this decision by stating that the National Weather Service provides "weather and climate data that inform the weather forecasting used to plan U.S. military deployments. Weather forecasts have long been critical factor in the success or failure of military operations."[37][38]
The NWS, through a variety of sub-organizations, issues different forecasts to users, including the general public. Although, throughout history, text forecasts have been the means of product dissemination, the NWS has been using more forecast products of a digital, gridded, image or other modern format.[39] Each of the122 Weather Forecast Offices (WFOs) send their graphical forecasts to a national server to be compiled in the National Digital Forecast Database (NDFD).[40] The NDFD is a collection of common weather observations used by organizations and the public, including precipitation amount, temperature, and cloud cover among other parameters. In addition to viewing gridded weather data via the internet, users can download and use the individual grids using a "GRIB2 decoder" which can output data asshapefiles,netCDF,GrADS, float files, and comma-separated value files.[41] Specific points in the digital database can be accessed using anXML SOAP service.
The National Weather Service issues many products relating to wildfires daily. For example, a Fire Weather Forecast, which have a forecast period covering up to seven days, is issued by local WFOs daily, with updates as needed. The forecasts contain weather information relevant to fire control and smoke management for the next 12 to 48 hours, such as wind direction and speed, and precipitation. The appropriate crews use this information to plan for staffing and equipment levels, the ability to conduct scheduled controlled burns, and assess the daily fire danger. Once per day, NWS meteorologists issue a coded fire weather forecast for specificUnited States Forest Service observation sites that are then input into theNational Fire Danger Rating System (NFDRS). This computer model outputs the daily fire danger that is then conveyed to the public in one of five ratings: low, moderate, high, very high, or extreme.[42]
The local Weather Forecast Offices of the NWS also, under a prescribed set of criteria, issue Fire Weather Watches andRed Flag Warnings as needed, in addition to issuing the daily fire weather forecasts for the local service area. These products alert the public and other agencies to conditions which create the potential for extreme fires. On the national level, the NWSStorm Prediction Center issues fire weather analyses for days one and two of the forecast period that provide supportive information to the local WFO forecasts regarding particular critical elements of fire weather conditions. These include large-scale areas that may experience critical fire weather conditions including the occurrence of "dry thunderstorms", which usually occur in thewestern U.S., and are not accompanied by any rain due to itevaporating before reaching the surface.[43]
State and federal forestry officials sometimes request a forecast from a WFO for a specific location called a "spot forecast", which are used to determine whether it will be safe to ignite aprescribed burn and how to situate crews during the controlling phase. Officials send in a request, usually during the early morning, containing the position coordinates of the proposed burn, the ignition time, and other pertinent information. The WFO composes a short-term fire weather forecast for the location and sends it back to the officials, usually within an hour of receiving the request.[43]
The NWS assists officials at the scene of large wildfires or other disasters, includingHAZMAT incidents, by providing on-site support through Incident Meteorologists (IMET).[44] IMETs are NWS forecasters specially trained to work with Incident Management Teams during severe wildfire outbreaks or other disasters requiring on-site weather support. IMETs travel quickly to the incident site and then assemble a mobile weather center capable of providing continuous meteorological support for the duration of the incident. The kit includes acell phone, alaptop computer, and communications equipment, used for gathering and displaying weather data such as satellite imagery or numerical forecast model output. Remote weather stations are also used to gather specific data for the point of interest,[44] and often receive direct support from the local WFO during such crises. IMETs, approximately 70 to 80 of which are employed nationally, can be deployed anywhere a disaster strikes and must be capable of working long hours for weeks at a time in remote locations under rough conditions.[45]
The NWS supports the aviation community through the production of several forecasts. Each area's WFO has responsibility for the issuance ofTerminal Aerodrome Forecasts (TAFs) forairports in their jurisdiction.[46] TAFs are concise, coded 24-hour forecasts (30-hour forecasts for certain airports) for a specific airport, which are issued every six hours with amendments as needed. As opposed to a public weather forecast, a TAF only addresses weather elements critical to aviation; these include wind,visibility,cloud cover andwind shear.
The National Weather Service operates 122 local offices, known as Weather Forecast Offices (WFOs), to issue products specific to those areas. Each WFO maintains a specific area of responsibility spanning multiple counties, parishes or other jurisdictions within the United States – which, in some areas, cover multiple states – or individual possessions; the local offices handle responsibility of composing and disseminating forecasts and weather alerts to areas within their region of service. Some of the products that are only issued by the WFOs aresevere thunderstorm andtornado warnings, flood,flash flood, and winter weather watches and warnings, some aviation products, and local forecast grids. The forecasts issued by a WFO are available on their individual pages within the Weather.gov website, which can be accessed through either forecast landing pages (which identify the office that disseminates the weather data) or via the alert map featured on the main page of the National Weather Service website.
Daily river forecasts are issued by the thirteen River Forecast Centers (RFCs) using hydrologic models based on rainfall, soil characteristics, precipitation forecasts, and several other variables. The first such center was founded on September 23, 1946.[47] Some RFCs, especially those in mountainous regions, also provide seasonal snow pack and peak flow forecasts. These forecasts are used by a wide range of users, including those inagriculture,hydroelectric dam operation, andwater supply resources.
Twenty-one NWS Center Weather Service Units (CWSUs) are collocated with theFederal Aviation Administration (FAA)Air Route Traffic Control Centers (ARTCC). Their main responsibility is to provide up-to-the-minute weather information and briefings to the Traffic Management Units and control room supervisors. Special emphasis is given to weather conditions that could be hazardous to aviation or impede the flow of air traffic in theNational Airspace System. Besides scheduled and unscheduled briefings for decision-makers in the ARTCC and other FAA facilities, CWSU meteorologists also issue two unscheduled products. The Center Weather Advisory (CWA) is an aviation weather warning for thunderstorms, icing, turbulence, and lowcloud ceilings and visibilities. The Meteorological Impact Statement (MIS) is a two- to 12-hour forecast that outlines weather conditions expected to impact ARTCC operations.[48]
The Aviation Weather Center (AWC), located inKansas City, Missouri, is a central aviation support facility operated by the National Weather Service, which issues two primary products:
The Storm Prediction Center (SPC) inNorman, Oklahoma issues severe thunderstorm and tornado watches in cooperation with local WFOs which are responsible for delineating jurisdictions affected by the issued watch, and SPC also issues mesoscale discussions focused upon possible convective activity. SPC compiles reports of severe hail, wind, or tornadoes issued by local WFOs each day when thunderstorms producing such phenomena occur in a given area, and formats the data into text and graphical products. It also provides forecasts on convective activity through day eight of the forecast period (most prominently, the threat of severe thunderstorms, the risk of which is assessed through a tiered system conveyed among six categories – general thunderstorms, marginal, slight, enhanced, moderate, or high – based mainly on the expected number of storm reports and regional coverage of thunderstorm activity over a given forecast day), and is responsible for issuing fire weather outlooks, which support local WFOs in the determination of the need for Red Flag Warnings.
TheWeather Prediction Center inCollege Park, Maryland provides guidance for future precipitation amounts and areas where excessive rainfall is likely,[49] while local NWS offices are responsible for issuing Flood Watches, Flash Flood Watches, Flood Warnings, Flash Flood Warnings, and Flood Advisories for their local County Warning Area, as well as the official rainfall forecast for areas within their warning area of responsibility. These products can and do emphasize different hydrologic issues depending on geographic area, land use, time of year, as well as other meteorological and non-meteorological factors (for example, during the early spring or late winter a Flood Warning can be issued for anice jam that occurs on a river, while in the summer a Flood Warning will most likely be issued for excessive rainfall).
In recent years, the NWS has enhanced its dissemination of hydrologic information through the Advanced Hydrologic Prediction Service (AHPS).[50] The AHPS allows anyone to view near real-time observation and forecast data for rivers, lakes and streams. The service also enables the NWS to provide long-range probabilistic information which can be used for long-range planning decisions.
The National Weather ServiceOcean Prediction Center (OPC) inCollege Park, Maryland[51] issuesmarine products for areas that are within the national waters of the United States. NWS national centers or Weather Forecast Offices issue several marine products:
TheNational Hurricane Center (NHC) and theCentral Pacific Hurricane Center (CPHC), respectively based inMiami, Florida andHonolulu, Hawaii, are responsible for monitoring tropical weather in theAtlantic, and central and easternPacific Oceans. In addition to releasing routine outlooks and discussions, the guidance center initiates advisories and discussions on individual tropical cyclones, as needed. If a tropical cyclone threatens the United States or its territories, individual WFOs begin issuing statements detailing the expected effects within their local area of responsibility. The NHC and CPHC issue products including tropical cyclone advisories, forecasts, and formation predictions, and warnings for the areas in the Atlantic and parts of the Pacific.
TheClimate Prediction Center (CPC) inCollege Park, Maryland is responsible for all of the NWS's climate-related forecasts. Their mission is to "serve the public by assessing and forecasting the impacts of short-term climate variability, emphasizing enhanced risks of weather-related extreme events, for use in mitigating losses and maximizing economic gains." Their products cover time scales from a week to seasons, extending into the future as far as technically feasible, and cover the land, the ocean and the atmosphere, extending into the stratosphere. Most of the products issued by the center cover theContiguous U.S. andAlaska.
Additionally, Weather Forecast Offices issue daily and monthly climate reports for official climate stations within their area of responsibility. These generally include recorded highs, lows and other information (including historical temperature extremes, fifty-year temperature and precipitation averages, anddegree days). This information is considered preliminary until certified by theNational Climatic Data Center.
TheSpace Weather Prediction Center (SWPC), located in Boulder, Colorado, is responsible for monitoring and issuing forecasts, alerts, and warnings related to solar activity that may affect terrestrial activities. In particular, SWPC is concerned with how events such ascoronal mass ejections (CMEs),geomagnetic storms,solar flares, and other phenomena can impactelectric power transmission,GPS systems,HF radio andsatellite communications, as well as other potential impacts.
SWPC also issuesaurora forecasts for both theNorthern Hemisphere andSouthern Hemisphere.
The primary network of surface weather observation stations in the United States is composed ofAutomated Surface Observing Systems (ASOS). The ASOS program is a joint effort of the National Weather Service (NWS), automatic weather station(AWS), the Federal Aviation Administration (FAA), and the Department of Defense (DOD).[52] ASOS stations are designed to support weather forecast activities and aviation operations and, at the same time, support the needs of the meteorological, hydrological, and climatological research communities. ASOS was especially designed for the safety of the aviation community, therefore the sites are almost always located near airport runways. The system transmits routine hourly observations along with special observations when conditions exceed aviation weather thresholds (e.g. conditions change fromvisual meteorological conditions toinstrument meteorological conditions). The basic weather elements observed are: sky condition, visibility, present weather, obstructions to vision, pressure, temperature,dew point, wind direction and speed, precipitation accumulation, and selected significant remarks. The coded observations are issued asMETARs and look similar to this:
METAR KNXX 121155Z 03018G29KT 1/4SM +TSSN FG VV002 M05/M07 A2957 RMK PK WND 01029/1143 SLP026SNINCR 2/10 RCRNR T2 SET 6///// 7//// 4/010 T10561067 11022 21056 55001 PWINO PNO FZRANO
Getting more information on the atmosphere, more frequently, and from more locations is the key to improving forecasts and warnings. Due to the large installation and operating costs associated with ASOS, the stations are widely spaced. Therefore, theCooperative Observer Program (COOP), a network of approximately 11,000 mostly volunteer weather observers, provides much of the meteorological and climatological data to the country. The program, which was established in 1890 under the Organic Act, currently has a twofold mission:
The National Weather Service also maintains connections with privately operatedmesonets such as theCitizen Weather Observer Program for data collection, in part, through theMeteorological Assimilated Data Ingest System (MADIS). Funding is also provided to theCoCoRaHS volunteer weather observer network through parent agency NOAA.
NWS forecasters need frequent, high-quality marine observations to examine conditions for forecast preparation and to verify their forecasts after they are produced. These observations are especially critical to the output ofnumerical weather models because large bodies of water have a profound impact on the weather. Other users rely on the observations and forecasts for commercial and recreational activities. To help meet these needs, the NWS'sNational Data Buoy Center (NDBC) inHancock County, Mississippi operates a network of about 90 buoys and 60 land-based coastal observing systems (C-MAN). The stations measure wind speed, direction, and gust; barometric pressure; and air temperature. In addition, all buoy and some C-MAN stations measuresea surface temperature, and wave height and period.[53] Conductivity and water current are measured at selected stations. All stations report on an hourly basis.
Supplemental weather observations are acquired through theUnited States Voluntary Observing Ship (VOS) program.[54] It is organized for the purpose of obtaining weather and oceanographic observations from transiting ships. An international program underWorld Meteorological Organization (WMO) marine auspices, the VOS has 49 countries as participants. The United States program is the largest in the world, with nearly 1,000 vessels. Observations are taken by deck officers, coded in a special format known as the "ships synoptic code", and transmitted in real-time to the NWS. They are then distributed on national and international circuits for use by meteorologists in weather forecasting, by oceanographers, ship routing services, fishermen, and many others. The observations are then forwarded for use by the National Climatic Data Center (NCDC) inAsheville, North Carolina.
Operational
Reduced
ClosedUpper air weather data is essential for weather forecasting and research. The NWS operates 92radiosonde locations inNorth America and ten sites inthe Caribbean. A small, expendable instrument package is suspended below a 2 metres (6.6 ft) wide balloon filled withhydrogen orhelium, then released daily at or shortly after 1100 and 2300UTC, respectively. As the radiosonde rises at about 300 meters/minute (1,000 ft/min), sensors on the radiosonde measure profiles of pressure, temperature, and relative humidity. These sensors are linked to a battery-powered radio transmitter that sends the sensor measurements to a ground receiver. By tracking the position of the radiosonde in flight, information on wind speed and direction aloft is also obtained. The flight can last longer than two hours, and during this time the radiosonde can ascend above 35 km (115,000 ft) and drift more than 200 km (120 mi) from the release point. When the balloon has expanded beyond its elastic limit and bursts (about 6 m or 20 ft in diameter), a small parachute slows the descent of the radiosonde, minimizing the danger to lives and property. Data obtained during the flights is coded and disseminated, at which point it can be plotted on aSkew-T or Stuve diagram for analysis. In recent years, the National Weather Service has begun incorporating data fromAMDAR in its numerical models (however, the raw data is not available to the public).
Due to cuts to theNOAA under the second presidency of Donald Trump, a number of sites had reduced or eliminated launches.[55]
The National Weather Service has developed a multi-tier concept for forecasting or alerting the public to all types of hazardous weather:
Short-fusedweather warnings and advisories issued by local NWS forecast offices are generally less than 500–5,000 square miles (1,300–12,900 km2) in area. Warnings for severe local storms are intended to be issued preceding the arrival of severe weather at a particular locale by one hour or less; the NWS also issues warnings and advisories for various hydrological and non-hydrological events includingfloods, non-thunderstorm high winds,winter storms, intense heat or cold, fire weather and marine hazards, which vary in timepsan depending on the weather situation (inland and coastal warnings for tropical cyclones are issued by theNational Hurricane Center (NHC), a guidance center of the National Oceanic and Atmospheric Administration). The NWS defines a warning as a "hazardous weather or hydrologic event [that] is occurring, is imminent, or has a very high probability of occurring" and an advisory as "[highlighting] special weather conditions that are less serious than a warning [...] for events that may cause significant inconvenience, and if caution is not exercised, [..] could lead to situations that may threaten life and/or property."[56][57] In earnest, they indicate that hazardous weather conditions are occurring that may pose a risk to life and property, and are intended to direct the general public to take immediate action and heed safety precautions; it also has the side purpose of directing emergency management personnel to be on standby in case the weather situation leads to property damage or casualties. Severe thunderstorm and flood warnings indicate that organized severe thunderstorms or flooding are occurring, whereas tornado warnings are issued if a storm is indicated to be producing an observed tornado or exhibits strong, low-level rotation.[58]
The process of issuing a warning or advisory begins with observations of a hydrological orextreme weather event that is either occurring at present (through radar imagery, reports from local television and radio stations, or ground observations by local law enforcement, civil defense officials, media outlets or storm spotters) or is forecast to occur within 12 to 24 hours. If after collaboration a warning or advisory is deemed necessary, the Weather Forecast Office will generate a bulletin product via the Advance Weather Interactive Processing System (AWIPS) and then disseminate the alert through various communication routes accessed by the media and various agencies, on the internet, toNOAA satellites, and onNOAA Weather Radio.[59]
The product outlines the alert type, the issuing WFO, the sections of government subdivisions (counties,parishes,boroughs orindependent cities) covered by the alert, and its time of expiration (based on the localtime zone). Some products – particularly for severe thunderstorm, tornado and flood warnings – include a tag requestingEmergency Alert System activation to trigger public alert messages via television, radio stations, NOAA Weather Radio, and smartphone apps and messaging services. For local storm events, the warning or advisory product also outlines a meteorological summary of the most recent storm location or local storm report issued prior to the product's issuance (including the approximate area instatute miles and estimated speed and direction), associated hazards, impacts, municipalities and designated land areas (and, if applicable, highway mile markers) covered by the alert, and boilerplate action messages informing the public of safety precautions they need to take or advising them to be vigilant of any warnings or weather statements that may be issued by their local National Weather Service office. A statement may be issued as a follow-up message to a warning, watch, or emergency, which may update, extend, or cancel the previously issued product or be used as a notification of significant weather for which no type of alert is currently in effect for a given location or is expected to be in effect.
In situations where a forecaster indicates a significant threat of extremely severe and life-threatening weather with an ongoing local weather event, enhanced wording may be used to note the heightened threat by a significant local storm event. In April 2012, the NWS introduced the Impact Based Warning system at its Weather Forecast Offices inWichita andTopeka,Kansas, andSpringfield,St. Louis andKansas City/Pleasant Hill,Missouri; the pilot project – which would expand to 80 Weather Forecast Offices overseen by the Central, Eastern, Southern and Western Region Headquarters by the spring of 2015 – incorporate message tags within the main body of the product describing the source of the hazard report, damage potential, and if applicable, radar indications or physical observations of tornadoes or the possibility of a tornado; hazards are also summarized at the close of the product text (describing estimated maximum hail size and wind gusts, and if applicable, if a storm has the potential to produce a tornado or in the event of a tornado warning, the basis of the warning or its damage threat).[60][61][62][63] The wording "Particularly Dangerous Situation" (PDS), which originated by the Storm Prediction Center for use in tornado watch products during expected high-end severe weather outbreaks, is subjectively issued.[64] It is occasionally issued with tornado warnings, normally if a large tornado capable of producing EF3 to EF5 damage or staying on the ground for long-duration – sometimes uninterrupted – paths has been reported (although atornado emergency may be issued in such cases if the tornado is expected to track into a densely populated area).[64] PDS warnings for other alerts occur with even less frequency, and their criteria varies depending on the alert type to which the wording is applied.[64]
Until September 30, 2007, local offices of the National Weather Service issued warnings for severe thunderstorms, tornadoes, flash flooding and marine hazards using geopolitical boundaries. The implementation of storm-based warnings on October 1, 2007, saw alerts for these meteorological or hydrological threats be delineated bypolygonal shapes in map-based weather hazard products, which outline the specified sections of government sub-jurisdictions that the warning covers, based on the projected path of a storm as determined by Doppler radar at the time of the warning's issuance; however, entire counties/parishes may sometimes be included in the warning polygon, especially if they encompass a small geographical area.[65] Warnings can be expanded, contracted (by removing jurisdictions where SPC and NWS forecasters no longer consider there to be a viable threat of severe weather, in which case, the storm-based warning may take on atrapezoidal representation in map-based watch products) or canceled before their set time of expiration by local NWS offices.
The NWS also releases Experimental Severe Weather Impact products for use onsocial media accounts maintained by local forecast offices as well as the Enhanced Data Display (EDD), an experimental pilot project created by theCharleston, West Virginia office's WeatherReady Nation initiative. The product provides a graphical depiction of short-fuse warnings and watches (specifically, tornado and severe thunderstorm watches and warnings, and flash flood warnings), showing a map of the warning area (outlined as a red polygon) and locations (including communities and interstate highways) that will be impacted. For severe thunderstorm, tornado and flash flood warnings, the estimated population count of the warned area and approximate totals of public schools and hospitals within the warning area as well as the maximum forecast intensity of hail size, wind gusts and potential tornadoes; tornado warnings referenced in the impact product also denote whether the warning was issued based on radar indication or ground confirmation.[66]
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NOAA Weather Radio All Hazards (NWR), promoted as "The Voice of the National Weather Service", is a special radio system that transmits uninterrupted weather watches, warnings and forecasts 24 hours a day directly from a nearby NWS office, with the broadcasts covering across 95–97% of the United States' population. The system – which is owned and operated by the NWS – consists of 1,030 transmitters, covering all 50 states; adjacent coastal waters;Puerto Rico; theU.S. Virgin Islands; and the U.S. Pacific Territories ofAmerican Samoa,Guam and theNorthern Mariana Islands. NWR requires a scanner or special radio receiver capable of picking up the signal. Individual NWR stations broadcast any one of seven allocated frequencies centered on 162MHz (known collectively as "weather band") in themarine VHF radio band. In recent years, national emergency response agencies such as theFederal Emergency Management Agency (FEMA) and theDepartment of Homeland Security have begun to take advantage of NWR's ability to efficiently reach a large portion of the U.S. population. When necessary, the system can also be used (in conjunction with theEmergency Alert System) to broadcast civil, natural and technological emergency and disaster alerts and information, in addition to those related to weather – hence the addition of the phrasing"All Hazards" to the name.
TheNOAA Weather Wire Service (NWWS) is a satellite data collection and dissemination system operated by the National Weather Service, which was established in October 2000. Its purpose is to provide state and federal government, commercial users, media and private citizens with timely delivery of meteorological, hydrological, climatological and geophysical information. All products in the NWWS data stream are prioritized, with weather and hydrologic warnings receiving the highest priority (watches are next in priority). NWWS deliverssevere weather and storm warnings to users in ten seconds or less from the time of their issuance, making it the fastest delivery system available. Products are broadcast to users via theAMC-4 satellite.
TheEmergency Managers Weather Information Network (EMWIN) is a system designed to provide the emergency management community with access to a set of NWS warnings, watches, forecasts and other products at no recurring cost. It can receive data via radio, internet, or a dedicatedsatellite dish, depending on the needs and capabilities of the user.[67]
NOAAPORT is a one-way broadcast communication system which provides NOAA environmental data and information in near real-time to NOAA and external users. This broadcast service is implemented by a commercial provider of satellite communications utilizingC band.
The agency's online service,Weather.gov, is a data rich website operated by the NWS that serves as a portal to hundreds of thousands of webpages and more than 300 different NWS websites. Through its homepage, users can access local forecasts by entering a place name in the main forecast search bar, view a rapidly updated map of active watches and warnings, and select areas related to graphical forecasts, national maps, radar displays, river and air quality data, satellite images and climate information. Also offered are XML data feeds of active watches and warnings, ASOS observations and digital forecasts for 5x5 kilometer (3 x 3 mile) grids. All of NWS local weather forecast offices operate their own region-tailored web pages, which provide access to current products and other information specific to the office's local area of responsibility. Weather.gov superseded theInteractive Weather Information Network (IWIN), the agency's early internet service which provided NWS data from the 1990s through the mid-2000s.
The WSR-88DDopplerweather radar system, also calledNEXRAD, was developed by the National Weather Service during the mid-1980s, and fully deployed throughout the majority of the United States by 1997. There are 158 suchradar sites in operation in the U.S., its various territorial possessions and selected overseas locations. This technology, because of its high resolution and ability to detect intra-cloud motions, is now the cornerstone of the agency's severe weather warning operations.
National Weather Service meteorologists use an advanced information processing, display and telecommunications system, the Advance Weather Interactive Processing System (AWIPS), to complete their work. These workstations allow them to easily view a multitude of weather and hydrologic information, as well as compose and disseminate products. The NWSEnvironmental Modeling Center was one of the early users of theESMF common modeling infrastructure. TheGlobal Forecast System (GFS) is one of the applications that is built on the framework.
In 2016, the NWS significantly increased the computational power of its supercomputers, spending $44 million on two new supercomputers fromCray andIBM. This was driven by relatively lower accuracy of NWS'Global Forecast System (GFS)numerical weather prediction model, compared to other global weather models.[68][69] This was most notable in the GFS model incorrectly predictingHurricane Sandy turning out to sea until four days before landfall; while theEuropean Centre for Medium-Range Weather Forecasts' model predicted landfall correctly at seven days. The new supercomputers increased computational processing power from 776 teraflops to 5.78 petaflops.[70][71][72]
As of 2016, the National Weather Service was organized as follows[74]
While respected as one of the premier weather organizations in the world, the National Weather Service has been perceived by someconservatives since the early 2000s as competing unfairly with the private sector.[75] National Weather Service forecasts and data, being works of the federal government, are in thepublic domain and thus available to anyone for free under United States law. From time to time, the situation receives official review to ascertain if a leaner, more efficient approach may be had by some degree of privatization.[76]
In 1983, theReagan administration and NOAA administratorJohn V. Byrne announced a proposal to sell all of the agency's weather satellites at auction with the intent to repurchase the weather data from private contractors that would acquire the satellites. Under the proposal, 30% of NOAA's workforce would be reviewed for potential layoffs, and certain specialty forecasts of agricultural and economic importance would be eliminated. NOAA also proposed outsourcing weather observation stations, NOAA Weather Radio, and computerized surface analysis to private companies. The proposal was met with negative reactions among the public, members of Congress, and consumer advocacy groups (including most notably,Ralph Nader), objecting to the possibility of weather information intended for the public domain being sold to private entities that would profit from the sale of the data. The proposal to sell the satellite network failed in a Congressional vote, while other aspects of the proposal to dismantle portions of NOAA's agencies were eventually scuttled.[28]
In 2005, Pennsylvania SenatorRick Santorum introduced theNational Weather Service Duties Act of 2005,[77] a bill which would have prohibited the NWS from freely distributing weather data. The bill was widely criticized by users of the NWS's services, especially by emergency management officials relying on the National Weather Service for information during fires, flooding, or severe weather. Groups such as theAircraft Owners and Pilots Association condemned the bill's restrictions on weather forecasting as threatening the safety of air traffic, noting that 40% of all aviation accidents are at least partially weather-related.[78] The bill attracted no cosponsors, and died in committee during the 2005 Congressional session.
During thefederal mass layoffs in 2025, probationary employees, who were easy to fire, received notices stating that they were "not fit for continued employment because your ability, knowledge and/or skills do not fit the agency’s current needs".[79] The companies chosen to assist theNational Oceanic and Atmospheric Administration had ties to Trump officials and those who filled leadership positions at NOAA both advocated for and stood to benefit financially from the privatization of weather forecasting.[80] TheBrookings Institution described the firings as setting the stage for greater privatization and automation of the federal government,[81] and Trump appointees had multiple conflicts of interest and financial ties to companies that would benefit as part of an effort to privatize government functions.[82]
Critics such asUniversity of Washington professor Cliff Mass[83] have claimed that NWS forecasts are not as accurate as they could be, and that this has resulted in inaccurate daily weather forecasts and dangerously bad predictions concerning the location and intensity of extreme weather events like blizzards and hurricanes. In 2016, the BritishMet Office, theEuropean Centre for Medium-Range Weather Forecasts (ECMWF), and the Northwest Regional Modeling Consortium in Seattle have been cited as producing more accurate predictions in certain circumstances. According to critics, causes include:[84]
The Next Generation Global Prediction System project at NWS[85] aims to address some of these criticisms by running a unified high-quality model that takes advantage of more recent research results.[citation needed]In 2016, the NOAA announced to develop The Next Generation Global Prediction System.[86]
The following is a list of the organization leaders of the National Weather Service and its predecessors, the United States Weather Bureau and the U.S. Army Signal Service, Division of Telegrams and Reports for the Benefit of Commerce. The first heads of the weather service, beginning in 1870 under military control, had the title of Chief Signal Officer. Once the organization became a civil agency in 1891, this position became known as the chief of the Weather Bureau. With the renaming of the organization in 1970, it has been the director of the National Weather Service.[87]
| No. | Image | Name | Term start | Term end | Refs |
|---|---|---|---|---|---|
| Established as theU.S. Army Signal Service,Division of Telegrams and Reports for the Benefit of Commerce in 1870 and headed by theU.S. Army Chief Signal Officer | |||||
| 1 |  | Albert J. Myer[a] | February 9, 1870 | August 24, 1880[b] | |
| acting |  | Richard C. Drum[a] | August 24, 1880 | December 15, 1880 | [88] |
| 2 |  | William Babcock Hazen[a] | December 16, 1880[c] | January 16, 1887[b] | [89][90][91] |
| 3 |  | Adolphus Greely[a] | March 3, 1887[d] | June 30, 1891 | [92][93] |
| RenamedUnited States Weather Bureau in 1891, transferred to theUSDA and headed by the chief of the Weather Bureau | |||||
| 4 |  | Mark Walrod Harrington[e] | July 1, 1891 | June 29, 1895 | [94][95][96] |
| acting | James R. Cook | July 1, 1895 | July 4, 1895 | [97] | |
| 5 |  | Willis Luther Moore | July 4, 1895 | April 16, 1913 | [98][99][100] |
| acting | Henry E. Williams[f] | April 17, 1913 | August 4, 1913 | [102][103] | |
| 6 | _portrait.jpg) | Charles F. Marvin | August 4, 1913 | January 30, 1934 | [104][105][106][107] |
| 7 |  | Willis Ray Gregg | January 31, 1934 | September 14, 1938[b] | [108][109][110] |
| acting | Charles C. Clark | September 14, 1938 | December 14, 1938 | ||
| acting | .jpg) | Francis Reichelderfer | December 14, 1938 | January 1, 1939 | |
| 8 | January 1, 1939 | September 30, 1963 | [111][112][113][114][115] | ||
| 9 |  | Robert M. White | October 1, 1963 | July 13, 1965 | [116][117][118] |
| acting |  | George Cressman[g] | July 13, 1965 | September 1, 1965 | |
| 10 | September 1, 1965 | January 15, 1979 | [119][120][121] | ||
| RenamedNational Weather Service in 1970, transferred toNOAA, and headed by the director of the National Weather Service. | |||||
| 11 | .jpg) | Richard E. Hallgren | February 12, 1979 | March 27, 1988 | [122][123] |
| 12 |  | Elbert W. "Joe" Friday, Jr. | March 28, 1988 | June 27, 1997 | [124][125][126][127] |
| acting | . | Robert S. Winokur | June 28, 1997 | February 25, 1998 | |
| 13 |  | John J. "Jack" Kelly, Jr. | February 26, 1998 | January 8, 2004 | [128][129] |
| 14 |  | David L. Johnson | January 9, 2004 | June 30, 2007 | [130][131] |
| acting |  | Mary Glackin | July 1, 2007 | September 1, 2007 | [132] |
| 15 |  | John L. "Jack" Hayes | September 2, 2007 | May 25, 2012 | [133][134] |
| acting |  | Laura Furgione | May 29, 2012 | February 9, 2013 | [135][136] |
| 16 |  | Louis Uccellini | February 10, 2013 | January 1, 2022 | [137][138][139] |
| acting |  | Mary C. Erickson | January 2, 2022 | June 6, 2022 | [140] |
| 17 |  | Ken Graham | June 7, 2022 | present | [141][142] |
Table notes:
