Ed. Note: This post is part of a series following the release of the 1940 Census  highlighting various Commerce agencies and their hard work on behalf of the American people during the 1940s through today
The 1940s was a pivotal decade for the National Weather Service and the entire field of meteorology. Advancements in technology during the ‘40s, spurred by World War II, provided the scientific foundation for modern day weather forecasting throughout the world.
The agency, founded by Ulysses S. Grant in 1870 and called the Weather Bureau, was originally housed in the War Department. It was later moved to the Department of Agriculture in 1890, and then in 1940 President Roosevelt transferred it to the Department of Commerce. In 1970 the agency was renamed the National Weather Service when it became part of the newly-created National Oceanic and Atmospheric Administration (NOAA) within the Department of Commerce.
In the 1940s, most of the modern technology forecasters rely on today had not yet been invented, such as satellites and super computers. Weather observations were painstakingly logged by hand.
By 1940, the Weather Bureau operated 35 radiosonde stations (weather balloons), allowing for the routine measurement of atmospheric pressure, temperature, humidity, wind direction and speed. In 1942, the Weather Bureau received 25 surplus radars from the military, launching the network of weather surveillance radars.
The Weather Bureau, in cooperation with local telephone companies, made weather forecasts more accessible to the public in a handful of large U.S. cities in 1940 with recorded forecasts the public could access by phone.
Both the Army and Navy established weather centers in the 1940s, and the Weather Bureau began training and sharing atmospheric data with the military. Weather forecasting played an important role in key battles that influenced the outcome of World War II, including the Battle of Midway in June 1942 and the decision to invade Normandy in June 1944. The Allies had the advantage of knowing weather conditions in the Western Hemisphere and over the Atlantic Ocean, which aided their success in battle. Many experienced forecasters were called to military duty to support the war effort in Europe and other parts of the world.
Several research projects were undertaken to support military flights and sea missions.
World War II sent women into the American workforce in droves, and weather forecasting was no exception. By 1945, more than 900 women were employed by the Weather Bureau as atmospheric observers and forecasters, as a result of filling positions of men during the war (see photo).
In 1946, the first two of an eventual 13 river forecast centers were established in Cincinnati and Kansas City, and in 1948 meteorologists with the U.S. Air Force issued the first-ever tornado warnings at Tinker Air Force Base.
Later in the decade, other advancements were explored and developed, like the use of computers for weather forecasting and the use of fax for transmitting weather maps. The 1940s also saw the first weather forecasts specifically to support battling forest fires.
Weather forecasting proved its value in the outcome of the war, and on the homefront, forecasters continued to be dedicated to the mission of protecting life and property. For example:
- In January 1943, flood forecasts produced by the Weather Bureau office in Sacramento helped stave off massive cattle losses. The warnings provided to the cattle industry allowed enough time to evacuate livestock from the bypasses and lowland areas. No loss of life was reported from this big flood event along the Sacramento River Basin, with credit going to the warnings provided by the Weather Bureau.
- In 1945, many thousands of people were evacuated from coastal Florida in advance of a land falling tropical storm and associated tornado. The warnings that led to the evacuations were credited for saving lives during this dangerous weather event.