This paper was inspired by conversation with Jason Lynn (NSSL) as the events of the day unfolded. We appreciate thought-provoking discussions with Dr. Erik Rasmussen (CIMMS/NSSL) and Dr. Chuck Doswell (NSSL). We also are grateful to Gary England (KWTV, Oklahoma City), Daphne Zaras (NSSL), Greg Stumpf (NSSL), Arthur Witt (NSSL), Mike Eilts (NSSL), Dale Morris (Oklahoma Climate Survey), Dr. Ken Crawford (Oklahoma Climate Survey/OU), and Dr. Ron Holle (NSSL) for providing photographs, satellite, radar, surface, and lightning data. We also thank Rob Carver (OU) and Mark Askelson (OU) for their assistance, as well as the three anonymous reviewers. This work was partially funded by NSF Grants EAR-9512145, ATM-9120009, and ATM-9617318.
Beebe, R. G., 1959: Notes on the Scottsbluff, Nebraska tornado, 27 June 1955. Bull. Amer. Meteor. Soc.,40, 109–116.
Bluestein, H. B., 1984: Further examples of low-precipitation severe thunderstorms. Mon. Wea. Rev.,112, 1885–1888.
——, and C. R. Parks, 1983: A synoptic and photographic climatology of low-precipitation severe thunderstorms in the Southern Plains. Mon. Wea. Rev.,111, 2034–2046.
Brewster, K., F. Carr, N. Lin, J. M. Straka, and J. Krause, 1994: A local analysis system for initializing real-time convective-scale models. Preprints, 10th Conf. on Numerical Weather Prediction, Portland, OR, Amer. Meteor. Soc., 596–598.
Brock, F. V., K. Crawford, R. Elliot, G. Cuperus, S. Stadler, H. Johnson, and M. Eilts, 1995: The Oklahoma Mesonet: A technical overview. J. Atmos. Oceanic Technol.,12, 5–19.
Brooks, H. E., C. A. Doswell, and J. Cooper, 1994: On the environments of tornadic and nontornadic mesocyclones. Wea. Forecasting,9, 606–617.
Browning, K. A., 1964: Airflow and precipitation trajectories within severe local storms which travel to the right of the winds. J. Atmos. Sci.,21, 634–639.
——, 1965: Some inferences about the updraft within a severe local storm. J. Atmos. Sci.,22, 669–678.
——, 1977: The structure and mechanisms of hailstorms. Hail: A Review of Hail Science and Hail Suppression, Meteor. Monogr., No. 38, Amer. Meteor. Soc., 1–39.
——, and R. J. Donaldson, 1963: Airflow and structure of a tornadic storm. J. Atmos. Sci.,20, 533–545.
Burgess, D. W., R. A. Brown, L. R. Lemon, and C. R. Safford, 1977:Evolution of a tornadic thunderstorm. Preprints, 10th Conf. on Severe Local Storms, Omaha, NE, Amer. Meteor. Soc., 84–89.
Chisholm, A. J., 1973: Radar case studies and airflow models. Alberta Hailstorms, Meteor. Monogr., No. 36, Amer. Meteor. Soc., 1–36.
Darkow, G. L., 1969: An analysis of over sixty tornado proximity soundings. Preprints, Sixth Conf. on Severe Local Storms, Chicago, IL, Amer. Meteor. Soc., 218–221.
Davies, J. M., 1993: Small tornadic supercells in the central Plains. Preprints, 17th Conf. on Severe Local Storms, St. Louis, MO, Amer. Meteor. Soc., 305–309.
Davies-Jones, R. P., 1984: Streamwise vorticity: The origin of updraft rotation in supercell storms. J. Atmos. Sci.,41, 2991–3006.
Doswell, C. A., 1996: What is a supercell? Preprints, 18th Conf. on Severe Local Storms, San Francisco, CA, Amer. Meteor. Soc., 641.
——, and D. W. Burgess, 1993: Tornadoes and tornadic storms: A review of conceptual models. The Tornado: Its Structure, Dynamics, Prediction, and Hazards, Geophys. Monogr., No. 79, Amer. Gepophys. Union, 161–172.
——, and E. N. Rasmussen, 1994: The effect of neglecting the virtual temperature correction on CAPE calculations. Wea. Forecasting,9, 625–629.
Emanuel, K. A., 1994: Atmospheric Convection. Oxford University Press, 580 pp.
Forbes, G. S., 1981: On the reliability of hook echoes as tornado indicators. Mon. Wea. Rev.,109, 1457–1466.
Fujita, T. T., 1958: Mesoanalysis of the Illinois tornadoes of 9 April 1953. J. Meteor.,15, 288–296.
——, 1960: A detailed analysis of the Fargo tornadoes of June 20, 1957. U.S. Weather Bureau Research Paper No. 42, 67 pp. [Available from National Technical Information Service, Springfield, VA 22161.].
Johns, R. H., and C. A. Doswell, 1992: Severe local storms forecasting. Wea. Forecasting,7, 588–612.
Kennedy, P. C., N. E. Westcott, and R. W. Scott, 1993: Single-Doppler radar observations of a mini-supercell tornadic thunderstorm. Mon. Wea. Rev.,121, 1860–1870.
Klemp, J. B., 1987: Dynamics of tornadic thunderstorms. Annu. Rev. Fluid Mech.,19, 369–402.
Knight, C. A., and L. J. Miller, 1993: First radar echoes from cumulus clouds. Bull. Amer. Meteor. Soc.,74, 179–188.
Knupp, K. J., J. Stalker, and E. W. McCaul Jr., 1998: An observational and numerical study of a mini-supercell storm. Atmos. Res.,49, 35–63.
Lemon, L. R., 1977: Severe thunderstorm evolution: Its use in a new technique for radar warnings. Preprints, 10th Conf. on Severe Local Storms, Omaha, NE, Amer. Meteor. Soc., 77–83.
——, and C. A. Doswell, 1979: Severe thunderstorm evolution and mesocyclone structure as related to tornadogenesis. Mon. Wea. Rev.,107, 1184–1197.
——, D. W. Burgess, and R. A. Brown, 1978: Tornadic thunderstorm airflow and morphology derived from single-Doppler radar measurements. Mon. Wea. Rev.,106, 48–61.
Lilly, D. K., 1986: The structure, energetics, and propagation of rotating convective storms. Part II: Helicity and storm stabilization. J. Atmos. Sci.,43, 126–140.
Markowski, P. M., E. N. Rasmussen, and J. M. Straka, 1998: A preliminary investigation of the importance of helicity “location” in the hodograph. Preprints, 19th Conf. on Severe Local Storms, Minneapolis, MN, Amer. Meteor. Soc., 230–233.
Marwitz, J. D., 1972: The structure and motion of severe hailstorms. Part I: Supercell storms. J. Appl. Meteor.,11, 166–179.
McCaul, E. W., Jr., 1991: Buoyancy and shear characteristics of hurricane tornado environments. Mon. Wea. Rev.,119, 1954–1978.
——, 1993: Observations and simulations of hurricane-spawned tornadic storms. The Tornado: Its Structure, Dynamics, Prediction, and Hazards, Geophys. Monogr., No. 79, Amer. Geophys. Union, 119–142.
——, and M. L. Weisman, 1996: Simulations of shallow supercell storms in landfalling hurricanes. Mon. Wea. Rev.,124, 408–429.
Miner, T. J., and J. M. Fritsch, 1997: Lake-effect rain events. Mon. Wea. Rev.,125, 3231–3248.
Moller, A., C. A. Doswell, J. McGinley, S. Tegtmeier, and R. Zipser, 1974: Field observations of the Union City tornado in Oklahoma. Weatherwise,27, 68–77.
Monteverdi, J. P., and J. Quadros, 1994: Convective and rotational parameters associated with three tornado episodes in northern and central California. Wea. Forecasting,9, 285–300.
Peterson, R. E., 1976: The Sunray tornado. Bull. Amer. Meteor. Soc.,57, 805–807.
Rasmussen, E. N., and R. B. Wilhelmson, 1983: Relationships between storm characteristics and 1200 GMT hodographs, low-level shear, and stability. Preprints, 13th Conf. on Severe Local Storms, Boston, MA, Amer. Meteor. Soc., J5–J8.
——, and D. O. Blanchard, 1998: A baseline climatology of sounding-derived supercell and tornado forecast parameters. Wea. Forecasting,13, 1148–1164.
Ray, P. S., B. C. Johnson, K. W. Johnson, J. S. Bradberry, J. J. Stephens, K. K. Wagner, R. B. Wilhelmson, and J. B. Klemp, 1981: The morphology of several tornadic storms on 20 May 1977. J. Atmos. Sci.,38, 1643–1663.
Rotunno, R., and J. B. Klemp, 1982: The influence of the shear-induced pressure gradient on thunderstorm motion. Mon. Wea. Rev.,110, 136–151.
——, and ——, 1985: On the rotation and propagation of simulated supercell thunderstorms. J. Atmos. Sci.,42, 271–292.
Stalker, J. R., K. R. Knupp, and E. W. McCaul Jr., 1993: A numerical and observational study of an atypical “miniature” supercell storm. Preprints, 17th Conf. on Severe Local Storms, St. Louis, MO, Amer. Meteor. Soc., 191–195.
Stout, G. E., and F. A. Huff, 1953: Radar records Illinois tornadogenesis. Bull. Amer. Meteor. Soc.,34, 281–284.
Wakimoto, R. M., and V. N. Bringi, 1988: Dual-polarization observations of microbursts associated with intense convection: The 20 July storm during the MIST project. Mon. Wea. Rev.,116, 1521–1539.
WATADS, 1998: Reference guide for version 10.0. 72 pp. [Available from Storm Scale Applications Division, National Severe Storms Laboratory, 1313 Halley Circle, Norman, OK 73069.].
Weisman, M. L., and J. B. Klemp, 1982: The dependence of numerically simulated convective storms on vertical wind shear and buoyancy. Mon. Wea. Rev.,110, 504–520.
——, and ——, 1984: The structure and classification of numerically simulated convective storms in directionally-varying wind shears. Mon. Wea. Rev.,112, 2479–2498.
——, and ——, 1986: Characteristics of isolated convective storms. Mesoscale Meteorology and Forecasting, P. S. Ray, Ed., Amer. Meteor. Soc., 331–358.
——, M. S. Gilmore, and L. J. Wicker, 1998: The impact of convective storms on their local environment: What is an appropriate ambient sounding? Preprints, 19th Conf. on Severe Local Storms, Minneapolis, MN, Amer. Meteor. Soc., 238–241.
Wicker, L. J., and L. Cantrell, 1996: The role of vertical buoyancy distributions in miniature supercells. Preprints, 18th Conf. on Severe Local Storms, San Francisco, CA, Amer. Meteor. Soc., 225–229.
Ziegler, C. L., and E. N. Rasmussen, 1998: The initiation of moist convection at the dryline: Forecasting issues from a case study perspective. Wea. Forecasting,13, 1106–1131.