[Deathwatch] George P. Cressman, meteorologist, 88

[Deathwatch Central <cdw@slick.org>]

George P. Cressman, 88; meteorologist made forecasting a science
By Matt Schudel

May 13, 2008

WASHINGTON ? George P. Cressman, a former National Weather Service
director who took the lead in applying computers to meteorology and
helped change weather forecasting from a form of cloud-gazing guesswork
to a codified science, has died. He was 88.

Cressman, who was diagnosed with Alzheimer's disease, died April 17 at
the National Lutheran Home in Rockville, Md. 

In the 1950s, Cressman developed the first program that could produce
accurate and reliable forecasts prepared by computer, which led to a
monumental change in how weather is predicted and brought meteorology
into the computer age.

As director of the Weather Service from 1965 to 1979, Cressman expanded
the number of local weather radars, developed a nationwide weather
radio network and introduced systems to provide early warnings of
tornadoes and flash floods. He also made important contributions to
cooperative meteorological efforts around the globe.

"He really, truly was a giant in meteorology," said Richard Hallgren,
who succeeded Cressman as National Weather Service director.
"Worldwide, he was extraordinarily well-known. He is one of the few who
have contributed to so many things."

In the late 1940s, meteorologists were among the first scientists
attempting to harness the new technology of computers. They had little
sustained success until Cressman was named director of the federal
Joint Numerical Weather Prediction Unit in Suitland, Md., in 1954.
Using an IBM 701 computer, he recorded the weather conditions at
equally spaced points around the world, then devised a program that
allowed the computer to produce forecasts derived from the cumulative
data.

"At the time, that was a major breakthrough," said Ron McPherson,
executive director emeritus of the American Meteorological Society.
"Before that was done, forecasting was mostly an art" based on
extrapolations from hand-drawn weather charts.

"When computers came in, forecasting became much more of a science,"
McPherson added. "It started, literally, a revolution in forecasting."

George Parmley Cressman was born Oct. 7, 1919, in West Chester, Pa.
After graduating from Pennsylvania State University, Cressman studied
meteorology in a military course at New York University, then served as
a forecaster with the Army Air Forces. In January 1943, he began
teaching meteorology to military students at the University of Chicago,
where he became a protege of Carl-Gustaf Rossby, a renowned
meteorologist who identified the jet stream.

Cressman manned such outposts of the U.S. Weather Bureau as Lewistown,
Mont., Homestead, Fla., and Mount Home, Idaho, before receiving his
doctorate from the University of Chicago in 1949. He then worked at the
Air Force's central weather command at Andrews Air Force Base outside
Washington, seeking ways to improve the scientific validity of weather
predictions. In the early 1950s, he compiled forecasts for atomic bomb
tests in the Nevada desert.

In 1955, one year after Cressman began to concentrate on applying
computers to meteorology, the Weather Bureau (renamed the National
Weather Service in 1967) was issuing its first computer-generated
forecasts. The "Cressman Analysis," or "Cressman Method," as it became
known, greatly refined forecasting methods and gave rise to what
meteorologists call "numerical weather prediction."

"That is an achievement that, I think, 100 years from now he'll still
be known for," Hallgren said.

In the early 1960s, when Cressman was director of the National
Meteorological Center, which was the government's joint military and
civilian forecasting unit at the time, he instigated efforts to share
weather data with the Soviet Union. He continued to expand the use of
computers in weather forecasting throughout the 1960s.

As director of the Weather Service, Cressman added 100 weather radars
to the national network in the 1970s and established dozens of Weather
Service branches to provide accurate local forecasts across the
country. He stepped down in 1979 but continued to work as a consultant
to weather services in China, Spain and Brazil for several years. He
was president of the American Meteorological Society and received the
International Meteorological Organization Prize -- the highest honor in
his field -- in 1978.

His first wife of 32 years, Nelia Hazard Cressman, died in 1974.

Survivors include his wife of 32 years, Frances Cressman, of North
Bethesda, Md.; four children from his first marriage; a brother; nine
grandchildren; and 10 great-grandchildren.

Many thanks to Deathwatch Central for posting this obituary