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The Thunderstorm Project

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The Thunderstorm Project The Thunderstorm Project 18th Conference on Severe Local Storms Luncheon Speech* Roscoe R. Braham Jr. Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University at Raleigh, Raleigh, North Carolina 1. Introduction In August 1940 a Penn Central DC-3 went down in a thunderstorm near Lovettsville, Virginia, killing Thank you, Dr. Biggerstaff. Ladies and Gentlemen, Senator Lundeen from Minnesota and 24 others. At I appreciate the opportunity to talk to you about the the time it was the worst accident in the history of Thunderstorm Project (TSP), as we approach the 50th American commercial aviation. This was not the first, anniversary of its first field season. nor the last, commercial airliner to go down in an Perhaps it would be more appropriate if this talk encounter with a thunderstorm, but it must have were given by Dr. Horace Byers, who was director caught the attention of Congress (Washington Post of the Thunderstorm Project. Unfortunately his physi- 1940; CAB 1940). cal condition prevents him from traveling. I talked In July 1943 an American Airlines DC-3 crashed with him recently, and he sends his regards. It would during thunderstorm conditions near Bowling Green, be appropriate for us to send him our best wishes. For Kentucky. The Civil Aeronautics Board report of that this purpose I am passing around a card for your greet- accident should be very interesting to many attend- ings and signatures. ing this conference (CAB 1944). I quote: In the spring of 1924, a young U.S. Weather Bu- reau meteorologist began a series of free-balloon It is reasonable to assume that the flight entered flights from Scott Field, near St. Louis, to trace the the (storm) at the planned altitude of 2000 ft movement of midlevel air parcels in midlatitude cy- (approximately 1300 ft above the terrain). clones and anticyclones (Meisinger 1924). On the Within the storm, the flight encountered a downdraft. Assuming that the crew main- 10th flight, about 7 hours after takeoff, and near the tained constant power and airspeed after strik- town of Monticello, Indiana, the balloon encountered ing the . downdraft, the airplane would have thunderstorms. Can you imagine—riding in an open been losing altitude at a rate substantially equal basket suspended below a balloon filled with hydro- to the vertical velocity of the surrounding gen and trailing a drag rope and radio antenna in the air. ... As a downdraft approaches the ground, midst of thunderstorms? It appears that the balloon its vertical velocity is necessarily checked, and was struck by lightning. The resulting explosion the moving air fans out into a horizontal killed the meteorologist (Jakl 1925). That meteorolo- wind. ... It is probable that by the time the air- gist was Clarence Leroy Meisinger. The Meisinger craft had reached an altitude of 200 feet above Award given each year by the AMS [American the ground . the direct influence of the Meteorological Society] commemorates the contribu- downdraft in forcing the airplane down would . have disappeared. (However, if tions of this meteorologist who became a casualty of we assume that) the airplane as it approached thunderstorms. the ground . .. passed out of the downdraft into a tail wind. The immediate effect. would ^Edited text of luncheon talk given at the 18th Conference on have been to increase the angle of attack. Severe Local Storms, San Francisco, California, 21 February At the same time the airspeed would have been 1996. decreased by the velocity of the tailwind. An ©1996 American Meteorological Society immediate loss of lift would have resulted. ts ulletin of the American Meteorological Society 1835 Unauthenticated | Downloaded 10/03/21 07:10 PM UTC The report goes on to stress the need to intensify ef- America in Congress assembled, that the Chief forts to study vertical air currents in thunderstorms and to of the Weather Bureau is authorized and di- analyze the behavior expected of an airplane that passes rected to investigate fully and thoroughly the quickly from a downdraft into a tailwind. For a report internal structure of thunderstorms, particul arly the degree of turbulence within such storms, issued in 1944, it sounds rather modern doesn't it? and the development, maintenance, and mag- In the years immediately prior to and during nitude of downdrafts with a view to establish- World War II, thunderstorms were widely recognized ing methods by which the characteristics of as the most serious weather hazard to aviation. Several particular thunderstorms may be forecast and scientific and aeronautics advisory groups recom- methods by which the characteristics of such mended research to learn more about them. One of storms may be determined on visual observa- these groups was the Subcommittee on Meteorology tion from outside of the immediate thunder- of the National Advisory Committee on Aeronautics. storm area. The membership of that group included, among oth- ers: Dr. Reichelderfer, chief of the U.S. Weather We note the emphasis on observations from outside Bureau; Major Harry Wexler, Army Air Force; of the storm area; in 1945 airborne radar for weather Major A. Spilhaus, Signal Corp; Dr. Ross Gunn, Navy depiction had not yet been developed. Research Lab.; Capt. Howard Orville, U.S. Navy; Sections 2 and 3 of H.R. 164 authorized appropria- Dr. Henry Houghton, Massachusetts Institute of Tech- tions for such a study and for the cooperation of other nology; Dr. C.-G. Rossby, University of Chicago departments and independent agencies in carrying it out. (NACA 1945, 6). After hearings before the House Committee on In- The American Meteorological Society commemo- terstate and Foreign Commerce, H.R. 164 passed the rates four of these persons through awards and/or House of Representatives on 12 June 1946 and was sent scholarships: Drs. Reichelderfer, Houghton, and to the Senate, where it was assigned to the Committee Rossby, and Capt. Orville. The latter was the father on Commerce. It is not clear to me at this time when of our own Harry and Richard Orville, and the man the bill was taken up in the Senate. However, in 1948, for whom the AMS Orville Scholarship is named. when the Thunderstorm Project was drawing to a These were pioneers in meteorology in this country. close, the 80th Congress, 2nd Session passed Public They helped focus attention on the need for scientific Law 657, the wording of which was virtually identical studies of weather phenomena and helped to galva- to H.R. 164. Legislative action to support the field nize the Congress and the Weather Bureau into action, operations appears to have been through the appro- which led to the Thunderstorm Project. priations process. For the fiscal year beginning July It was into this background that the Thunderstorm 1945 Congress included $185,000 in the Weather Bu- Project was born. It could hardly have come at a more reau appropriations to begin this study of thunderstorms. propitious time. The end of World War II meant that for Dr. Reichelderfer selected Horace Byers, at the the first time suitable airplanes and large amounts of University of Chicago, as director of the new project. other equipment, and large numbers of trained person- Both Dr. Reichelderfer and Dr. Byers had had previ- nel, were available for a major weather research effort. ous experiences with thunderstorms. In a 1969 letter to Prof. Bernice Ackerman, Dr. Reichelderfer tells of some of his experiences. (This letter is in the posses- 2. Congressional action sion of the author.) In January 1945 Mr. Bulwinkle of North Carolina In airships and balloons, especially in the trans- introduced into the House of Representatives a bill ocean Zeppelin type there were many occasions when I had reason to be "trebly interested" in identified as H.R. 164, which authorized and directed convective up-rushes and thunderstorms. If I the chief of the Weather Bureau to provide safety in were to offer an amusing anecdote perhaps it aviation and to direct an investigation of the causes might be about the 1923 National Balloon Race and characteristics of thunderstorms. when the balloon I was in won Second Place Section 1 of this bill reads, and thus qualified for the International Race out of Brussels. Why did we place? Because we got Be it enacted by the Senate and the House of drawn into a thunderstorm, could not get out, Representatives of the United States of and were carried far enough to win! 1836 Vol. 77, No. 8, August 1 996 Unauthenticated | Downloaded 10/03/21 07:10 PM UTC An article in the 1923 Monthly Weather Review According to Dr. J. Fletcher (1996, personal commu- gives several details of Reichelderfer's flight (Samuels nication), Dr. Harry Wexler, a pilot and meteorolo- 1923). Lt. Reichelderfer and Lt. Lawrance, both of the gist in the Army Air Corps, was a major force in U.S. Navy, took off from Indianapolis, Indiana. shaping the operational plans. During the flight they passed through several cumu- The planes penetrated the storm at five different lus clouds where they rose 600-800 ft min-1 in spite levels, 5000 ft apart (5000, 10 000, 15 000, 20 000, of continuous valving of hydrogen. In, or near by, a and 25 000 ft). The objective was to obtain the maxi- cumulonimbus they were carried to 18 500 ft where mum number of traverses through each storm and to they remained for 30 min or more before they could sample storms in all stages of development. No storm descend to land near Glen Campbell, Kentucky, was to be avoided because it appeared too big. Storms 25 h, 42 min, and 489 miles from their takeoff. were detected and followed, and the airplanes controlled and vectored, using a large ground radar located near the operations area.
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