Weather Service, National

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WEATHER SERVICE, NATIONAL. The National Weather Service (NWS) provides weather forecasts, climate and hydrologic data, and storm warnings for the United States and its territories.

Congress approved the creation of a federal weather service on 9 February 1870. Originally part of the Army Signal Service, the service became known as the Weather Bureau when the Department of Agriculture took control in 1891. In 1940 the bureau was shifted to the Department of Commerce. In October 1970 the Weather Bureau became part of the newly created National Oceanic and Atmospheric Administration (NOAA), and was renamed the National Weather Service.

The original weather service made forecasts from Washington, D.C., and offered climatological aid to farmers and businesses. The first regular forecasts (then called "probabilities") were published in 1871. In 1873 flood warnings were issued, and by the 1890s fruit growers were receiving special warnings by telegraph.

General weather forecasts were decentralized into district centers in the 1890s. National forecasts were updated four times daily starting in 1939; the popular fiveday forecast appeared in 1940 and the thirty-day outlook was inaugurated in 1948. The Air Commerce Act of 1926 provided for the first regular aviation weather service. As forecasts improved, so did the means of communicating them: teletype (developed in the late 1920s) was followed by wire photo weather maps (1934) and facsimile transmission of weather maps (1950s), while radio and then television passed reports to the public.

Other midcentury innovations included recording rain gauges, the ceilometer, the telepsychrometer, and the recording river-flood gauge. Upper-air readings, once taken by weather balloons and kites, now were made by airplanes. Radar, developed as a military tool during World War II, greatly enhanced the bureau's weather-tracking abilities. The postwar growth of computers gave meteorologists another powerful new tool, allowing detailed data analysis and the creation of predictive models.

The National Aeronautics and Space Administration (NASA), founded in 1958, also relied on weather forecasts to make critical spacecraft launch and landing decisions. In turn, the new rockets allowed the launch of the first weather satellites. The TIROS-9 satellite, launched in January 1965, offered the first complete ongoing coverage of the daylight portions of the earth; it was followed by the Geostationary Operational Environmental Satellites (GOES), first launched in November 1965, and the first launch (July 1972) of the Landsat series. By the end of the twentieth century, weather satellites surrounded the globe and their photos had become a key element in forecasting.

In the 1990s the NWS underwent a $4.5 billion modernization program. Included was the nationwide installation of NEXRAD (Next Generation Warning Radar) with so-called Doppler radar, capable of tracking directional shifts in wind-carried rain and alerting meteorologists to developing tornadoes. The development of the Internet allowed the general public, for the first time, on-demand access to satellite photos and other detailed NWS data.

The modern National Weather Service is charged with tracking and predicting life-threatening phenomena like hurricanes, tornadoes, snowstorms, and heat waves, as well as weather conditions conducive to natural disasters like forest fires. The NWS also plays a critical role in commercial aviation, delivering national forecasts and developing sensitive technology for predicting wind shear, microbursts, and other dangerous conditions. In 2001 the weather service had roughly 4,800 employees and an annual operating budget of approximately $740 million.


Berger, Melvin. The National Weather Service. New York: John Day, 1971.

Shea, Eileen. A History off NOAA. Rockville, Md.: National Oceanic and Atmospheric Administration, 1987.

Whitnah, Donald R. A History of the United States Weather Bureau. Urbana: University of Illinois Press, 1961.

Ryan F.Holznagel

Donald R.Whitnah