William "Bill" Mason Gray (9 October 1929 – 16 April 2016) was emeritus professor of atmospheric science at Colorado State University (CSU), and the head of the Tropical Meteorology Project at CSU's Department of Atmospheric Sciences. He is widely regarded as a pioneer in the science of tropical cyclone forecasting and one of the world's leading experts on tropical storms. After retiring as a faculty member at CSU in 2005, Gray remained actively involved in both climate change and tropical cyclone research until his death. Early life and career Gray was born on 9 October 1929, in Detroit, Michigan, and was the eldest son of Ulysses S. Gray and Beatrice Mason Gray. His family moved to Washington, D.C. in 1939 where he graduated from Wilson High School. In 1952, Gray received a B.S. degree in geography from George Washington University before joining the United States Air Force in 1953. Over the next four years, he served as an overseas weather forecast officer, primarily stationed in the Azores and England. Upon returning to the United States in 1957, he began work as a research assistant at the University of Chicago Department of Meteorology from 1957 to 1961. During his time there, he earned a M.S. in meteorology 1959 and went on to earn a PhD in geophysical sciences in 1964 under the mentorship of Herbert Riehl. He joined Colorado State University (CSU) in 1961 as part of the Department of Atmospheric Science. Gray remained active in the Air Force Reserves until 1974, at which time he retired as a Lieutenant colonel. Following his retirement from the Reserves, he became a professor at CSU and went on to advise successful 20 PhD and 50 M.S. graduates. Eight of his students received awards from the American Meteorological Society while under his mentorship. Many of his students went on to become prominent members of the meteorological community, with several working at the National Hurricane Center. His last student was Philip Klotzbach, who later took over Gray's position as lead author of the CSU seasonal hurricane forecasts. Gray worked closely with the World Meteorological Organization throughout his career. Starting in 1978, he traveled to numerous countries establish or improve connections with meteorologists across the globe, a groundbreaking action. In 1985, he organized the first International Workshop on Tropical Cyclones in Bangkok, Thailand. Gray had many students and he offered them advice including his commandments. One