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Abstract
During March of 1948 Tinker Air Force Base was hit directly by two tornadoes during a period of only five days. The first tornado was the most destructive, to that point, ever to occur in Oklahoma. The second storm caused considerable additional damage and was remarkable in another, more significant, way. The first operational tornado forecast had been issued by Air Force Officers E. J. Fawbush and R. C. Miller a few hours before the tornado moved across the base. This extremely unusual meteorological situation, two tornadoes hitting the same location within five days, coupled with the fortuitous forecast of the event, had a profound impact on the evolution of operational severe weather forecasting in the United States. These events eventually stimulated the initiation of public severe thunderstorm forecasting by the Weather Bureau.
Miller often presented anecdotal accounts of the events leading up to the landmark forecast, for example, in seminars and interviews during a visit to the National Severe Storms Laboratory during March 1994. He often stressed that the remarkable similarity of the synoptic settings on 21 and 25 March 1948 helped give him and Fawbush the courage to issue the now famous forecast. In this paper the synoptic environments that led to the two tornado occurrences at Tinker are analyzed and discussed. There were indeed similarities; however, it is surprising how different many aspects of the storm settings actually were. Similarities and important differences are illustrated with a series of synoptic surface and upper-air charts. It is likely that development of a base severe weather plan following the tornado disaster of 20 March, in addition to the presence and exhortations of General F. S. Borum at the base weather station on 25 March, provided as great a motivation for the first tornado forecast as did the similarity of the synoptic settings.
Abstract
During March of 1948 Tinker Air Force Base was hit directly by two tornadoes during a period of only five days. The first tornado was the most destructive, to that point, ever to occur in Oklahoma. The second storm caused considerable additional damage and was remarkable in another, more significant, way. The first operational tornado forecast had been issued by Air Force Officers E. J. Fawbush and R. C. Miller a few hours before the tornado moved across the base. This extremely unusual meteorological situation, two tornadoes hitting the same location within five days, coupled with the fortuitous forecast of the event, had a profound impact on the evolution of operational severe weather forecasting in the United States. These events eventually stimulated the initiation of public severe thunderstorm forecasting by the Weather Bureau.
Miller often presented anecdotal accounts of the events leading up to the landmark forecast, for example, in seminars and interviews during a visit to the National Severe Storms Laboratory during March 1994. He often stressed that the remarkable similarity of the synoptic settings on 21 and 25 March 1948 helped give him and Fawbush the courage to issue the now famous forecast. In this paper the synoptic environments that led to the two tornado occurrences at Tinker are analyzed and discussed. There were indeed similarities; however, it is surprising how different many aspects of the storm settings actually were. Similarities and important differences are illustrated with a series of synoptic surface and upper-air charts. It is likely that development of a base severe weather plan following the tornado disaster of 20 March, in addition to the presence and exhortations of General F. S. Borum at the base weather station on 25 March, provided as great a motivation for the first tornado forecast as did the similarity of the synoptic settings.
Abstract
Return-flow events have been examined with the aid of a classification scheme that identifies each event with cold air masses that invade the Gulf during the cool season (February-March). These air masses were classified as either continental polar (cP), maritime polar (mP), or a mix of two or more of these basic types (MIX in future reference). Each event was viewed as a cycle in which the first phase represented an offshore flow typifying the cold-air outbreak over the Gulf and the second phase was associated with the return of modified air to the continent. Surface data for a 12-yr period, 1978–89, were used to make a statistical analysis of the event and each of its phases. The principal results of the study are 1) a total of 127 events occurred in this cool season over the 12-yr period. The relative percentages of mP, cP, and MIX air masses are 28%, 20%, and 52%, respectively. A median of 10.5 return-flow events occurred in the cool season where the MIX category was the dominant regime. The median duration for a return-flow cycle is 3,3, 5.2, and 6.2 days for mP, cP, and MIX, respectively, for the cool season. 2) The median duration of the offshore-flow phase for the cool season shows a wide range depending on airmass type with 30, 55, and 49 h as median times for mP, cP, and MIX, respectively. 3) The median duration of the return-flow phase for the cool season was significantly longer than the offshore-flow phase when all cases were examined en masse; but when the cases were segregated according to airmass type, the duration of the return flow for the cool season exhibited a wide range with 47, 57, and 62 h as median times for mP, cP and MIX, respectively.
In order to view the return-flow events in the Gulf of Mexico from a wider perspective, a historical summary of research on this event and similar events around the world is included.
Abstract
Return-flow events have been examined with the aid of a classification scheme that identifies each event with cold air masses that invade the Gulf during the cool season (February-March). These air masses were classified as either continental polar (cP), maritime polar (mP), or a mix of two or more of these basic types (MIX in future reference). Each event was viewed as a cycle in which the first phase represented an offshore flow typifying the cold-air outbreak over the Gulf and the second phase was associated with the return of modified air to the continent. Surface data for a 12-yr period, 1978–89, were used to make a statistical analysis of the event and each of its phases. The principal results of the study are 1) a total of 127 events occurred in this cool season over the 12-yr period. The relative percentages of mP, cP, and MIX air masses are 28%, 20%, and 52%, respectively. A median of 10.5 return-flow events occurred in the cool season where the MIX category was the dominant regime. The median duration for a return-flow cycle is 3,3, 5.2, and 6.2 days for mP, cP, and MIX, respectively, for the cool season. 2) The median duration of the offshore-flow phase for the cool season shows a wide range depending on airmass type with 30, 55, and 49 h as median times for mP, cP, and MIX, respectively. 3) The median duration of the return-flow phase for the cool season was significantly longer than the offshore-flow phase when all cases were examined en masse; but when the cases were segregated according to airmass type, the duration of the return flow for the cool season exhibited a wide range with 47, 57, and 62 h as median times for mP, cP and MIX, respectively.
In order to view the return-flow events in the Gulf of Mexico from a wider perspective, a historical summary of research on this event and similar events around the world is included.
Abstract
A return-flow case study is examined with the benefit of an unprecedented set of observations obtained during the Gulf of Mexico Experiment (GUFMEX). This case represents the return of modified continental air to the coastal plain in mid-February, and the work is designed to complement the classificatory study of return flow that is found in the companion paper by Crisp and Lewis.
Surface air trajectories are combined with land- and ocean-based upper-air data to methodically follow the airmass modification process from the exit point off the Gulf coastal plain to its subsequent entry point on land. Upper-air data from the U.S. Coast Guard (USCG) ship Salvia are especially valuable in this tracking process, but data from an oil platform at the edge of the continental shelf, as well as special onshore observations, significantly contribute to a macroscopic tracking of air involved in the return flow.
Results indicate that the warming and moistening process is complicated and requires careful assessment of both air-sea interaction processes and larger-scale vertical motion. The principal results are 1) the thermodynamic character of the returning air mass exhibits significant differences along the entire Gulf coast, and 2) the mixed-layer modeling theory appears to account for the warming and moistening processes for air in the central Gulf that tracks over the Loop Current. The processes determining the character and stratification of the air mass become very complicated, however, as the air approaches neutrally stable conditions and begins its northward track back toward land.
The paper concludes with a synopsis of the airmass modification process built upon a composite chart that combines analyses from the various observational platforms.
Abstract
A return-flow case study is examined with the benefit of an unprecedented set of observations obtained during the Gulf of Mexico Experiment (GUFMEX). This case represents the return of modified continental air to the coastal plain in mid-February, and the work is designed to complement the classificatory study of return flow that is found in the companion paper by Crisp and Lewis.
Surface air trajectories are combined with land- and ocean-based upper-air data to methodically follow the airmass modification process from the exit point off the Gulf coastal plain to its subsequent entry point on land. Upper-air data from the U.S. Coast Guard (USCG) ship Salvia are especially valuable in this tracking process, but data from an oil platform at the edge of the continental shelf, as well as special onshore observations, significantly contribute to a macroscopic tracking of air involved in the return flow.
Results indicate that the warming and moistening process is complicated and requires careful assessment of both air-sea interaction processes and larger-scale vertical motion. The principal results are 1) the thermodynamic character of the returning air mass exhibits significant differences along the entire Gulf coast, and 2) the mixed-layer modeling theory appears to account for the warming and moistening processes for air in the central Gulf that tracks over the Loop Current. The processes determining the character and stratification of the air mass become very complicated, however, as the air approaches neutrally stable conditions and begins its northward track back toward land.
The paper concludes with a synopsis of the airmass modification process built upon a composite chart that combines analyses from the various observational platforms.
Abstract
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Abstract
Editor’s note: The following, edited by Charlie Crisp, is taken from an unpublished manuscript (The Unfriendly Sky) by the late Colonel Robert C. Miller.
A Plea for Understanding
The close knit world of the tornado and severe thunderstorm forecaster often seems somewhat demented to those not knowledgeable in this discipline. This apparent derangement is based on our seemingly ghoulish expressions of joy and satisfaction displayed whenever we verify a tornado forecast. This aberration is not vicious; tornadoes in open fields make us happier than damaging storms and count just as much for or against us. We beg your indulgence, but point out the sad truism that we rise and fall by the blessed verification numbers. There is a fantastic feeling of accomplishment when a tornado forecast is successful. We are really nice people but odd.
Robert C. Miller, Colonel, USAF
Abstract
Editor’s note: The following, edited by Charlie Crisp, is taken from an unpublished manuscript (The Unfriendly Sky) by the late Colonel Robert C. Miller.
A Plea for Understanding
The close knit world of the tornado and severe thunderstorm forecaster often seems somewhat demented to those not knowledgeable in this discipline. This apparent derangement is based on our seemingly ghoulish expressions of joy and satisfaction displayed whenever we verify a tornado forecast. This aberration is not vicious; tornadoes in open fields make us happier than damaging storms and count just as much for or against us. We beg your indulgence, but point out the sad truism that we rise and fall by the blessed verification numbers. There is a fantastic feeling of accomplishment when a tornado forecast is successful. We are really nice people but odd.
Robert C. Miller, Colonel, USAF
The career of severe storm forecaster and teacher Colonel Robert Miller (1920–98) is historically reviewed and evaluated. His pathway to the position of recognized authority in severe storm forecasting is examined in light of his early education at Occidental College, his experiences as a weather officer in the Pacific Theatre during World War II (WWII), and his part in the bold and successful tornado forecast at Tinker Air Force Base in 1948.
We pay particular attention to Miller's development of a three-dimensional view of the severe storm environment in the precomputer age of the late 1940s—a viewpoint that remains central to current operational practice. This conceptual view led Miller and commander Ernest Fawbush to establish empirical criteria/rules that became the foundation of operational prediction at the military's Severe Weather Warning Center (SWWC). The success at the SWWC placed pressure on its civilian counterpart, the Severe Weather Unit (SWU) [later renamed the Severe Local Storms (SELS) unit] of the U.S. Weather Bureau. As part of our historical study, we explore and examine the circumstances that led to the spirit of competitiveness between these groups.
Finally, Miller's approach to forecaster training is discussed by reliance on reminiscences from his protégés. In the epilogue, we grapple with important issues related to forecaster education and training in light of Miller's philosophy.
The career of severe storm forecaster and teacher Colonel Robert Miller (1920–98) is historically reviewed and evaluated. His pathway to the position of recognized authority in severe storm forecasting is examined in light of his early education at Occidental College, his experiences as a weather officer in the Pacific Theatre during World War II (WWII), and his part in the bold and successful tornado forecast at Tinker Air Force Base in 1948.
We pay particular attention to Miller's development of a three-dimensional view of the severe storm environment in the precomputer age of the late 1940s—a viewpoint that remains central to current operational practice. This conceptual view led Miller and commander Ernest Fawbush to establish empirical criteria/rules that became the foundation of operational prediction at the military's Severe Weather Warning Center (SWWC). The success at the SWWC placed pressure on its civilian counterpart, the Severe Weather Unit (SWU) [later renamed the Severe Local Storms (SELS) unit] of the U.S. Weather Bureau. As part of our historical study, we explore and examine the circumstances that led to the spirit of competitiveness between these groups.
Finally, Miller's approach to forecaster training is discussed by reliance on reminiscences from his protégés. In the epilogue, we grapple with important issues related to forecaster education and training in light of Miller's philosophy.
