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The Hydrometeorological Prediction Center

A Brief History of the Hydrometeorological Prediction Center

Old surface analysis drawing tableSurface analysis in early days

The National Centers for Environmental Prediction (NCEP) is the central operational and research component of the National Weather Service (NWS). As the nation's primary center for the processing of meteorological data, its analyses and prognoses are the basis of all public and specialized forecasts issued by the NWS. NCEP also provide guidance to other government, military, private and international weather programs. 

The Hydrometeorological Prediction Center (HPC) is one of several Service Centers under the umbrella of NCEP. The HPC serves as a center of excellence in Quantitative Precipitation Forecasting, Medium Range Forecasting (three to seven days) and the interpretation of numerical weather prediction models. 

From the earliest days of the government's involvement in weather services (the NWS may be traced to 1870), it was apparent that a centralized facility would be necessary to effectively gather, organize and disseminate weather data on a national basis. The "center" during the early years occupied a single room co-located with the U. S. Army Signal Service in Washington, D. C. There, telegraphic reports of temperature, wind and pressure from around the country were plotted and analyzed. From these analyses, rudimentary forecasts were made for the following day. Washington shared some of its forecast duties with the advent of a field office system in the 1890s, but the central office still had the final say in cases of professional dispute. 

While the HPC's roots lie deep in the past, the organization can be most directly traced to the formation of the "WBAN Analysis Center" in downtown Washington, D. C. in December 1942. This unit was created by Executive Order at the height of World War II to coordinate and consolidate the efforts of the civilian (U.S. Weather Bureau), Army and Navy weather operations as they existed at the time. In addition to various analyses, the WBAN Center also provided medium range (3 to 5 day) outlooks from its Extended Forecast Section. 

The purpose of the WBAN Center was to not only assist forecasters in the field, but to also minimize duplication of effort during the wartime situation. This was done by centrally producing a wide array of diagnostic and forecast maps for national distribution. Initially, the charts were sent in coded form via teletype. Somewhat later, the installation of facsimile allowed for the direct transmission of graphics. Hundreds of maps were produced every day, including surface and upper air analyses, temperature and precipitation forecasts and prognostic surface charts. 

By the early 1950's, computers powerful enough to solve the fundamental equations of atmospheric motion in real-time were at last becoming available. Thus, the theoretical work of English physicist L.F. Richardson, who during World War I first proposed the use of numerical techniques in weather prediction, could finally be tested. The Joint Numerical Weather Prediction Unit (JNWPU) was formed in July 1954 to do just that. More broadly, JNWPU's objective was to apply the expanding field of computer technology to operational weather forecasting. 

The JNWPU was staffed and funded jointly by the Weather Bureau, Army and Navy, and was responsible for many of the early advances in automated analysis and forecasting. The first JNWPU computer, an IBM 701, was installed in March 1955, and the first numerical experimental forecasts (using a barotropic model) appeared one month later. The unit co-located with the renamed National Weather Analysis Center (NAWAC, formerly the WBAN Center), at Suitland, MD during the same year. 

The National Meteorological Center (NMC), the direct precursor to NCEP, came into being with the merging of NAWAC (including the Extended Forecast Section) and JNWPU in Federal Office Building #4 ("FOB 4") at Suitland in January 1958. NMC at once became the "nerve center" for weather data in the United States. NMC processed weather observations from around the globe and disseminated analyses and forecasts to customers throughout the U.S. and other countries. Research increased, with emphasis on developing faster and more accurate numerical techniques. It was the only such facility in the world at the time, and at least one publication described its creation as being "a milestone in the progress of meteorology." 

Constantly pursuing greater speed and reliability, NMC upgraded its computer investment substantially in the ensuing years, with each new system about 6 times more powerful than the one before. An IBM 704 replaced the 701 in 1957, and an IBM 7090 was installed in 1960. By 1963, the first operational baroclinic model was running on a new IBM 7094. The arrival of a CDC 6600 enabled the first global primitive equation (PE) model run to be made in June 1966. 

The accuracy of NMC's numerical guidance continued to increase into the 1970s, but especially significant gains were noted with the introduction of the high resolution PE model on an IBM 360/195 in 1978. By the late 1980s, a Cray Y-MP8 Class VII supercomputer served as NMC's mainframe system. It could produce a numerical forecast for all of North America out to 48 hours in less than 30 seconds, and was some 50,000 times more powerful than the IBM 701. While most NMC functions moved to their present location in the World Weather Building at Camp Springs, MD in January 1975, Suitland's "FOB 4" continued to house the Center's main computers until 1999 when an IBM SP was installed at a new site in Bowie, MD. This site was changed again in 2002 when a more powerful IBM Cluster was installed in Gaithersburg, MD. 

Five scientists have guided NMC (and NCEP) since its inception in 1958. George P. Cressman was the Center's first director, a post he held until leaving to become Director of the U. S. Weather Bureau in 1963. Frederick G. Shuman succeeded him and remained until retiring in 1981. William D. Bonner then became NMC's chief until Ronald D. McPherson arrived in 1990. Ronald D. McPherson served until he retired in July of 1998. Louis Uccellini was named Director of NCEP in January 1999. 

In October of 1995 NMC was reorganized into its current structure and renamed NCEP. The HPC, along with the Aviation Weather Center, Climate Prediction Center, Storm Prediction Center, Tropical Prediction Center are known as service centers. Two other centers, the Environmental Prediction Center and NCEP Central Operations, provide support to the service centers. At the time of the reorganization, the Space Environment Center also became part of NCEP. 

NCEP today continues to serve the National Weather Service most visibly through its array of centralized forecast guidance. Military and Federal Aviation Administration weather briefers also depend on NCEP's analysis and forecast products. In addition, NCEP provides computer support to such governmental agencies as the National Environmental Satellite Data and Information Service (NESDIS), and the NWS Techniques Development Laboratory (TDL). Business and industry leaders around the nation use NCEP's long range climate outlooks. On a broader scale, NCEP is a major node in the world-wide communications network that exchanges meteorological data and research with weather centers around the globe.

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Page last modified: Thursday, 01-Mar-2007 18:20:18 GMT