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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