Mobile Mesonet Observations on 3 May 1999

Paul M. Markowski Department of Meteorology, The Pennsylvania State University, University Park, Pennsylvania

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Abstract

Two long-lived tornadic supercells were sampled by an automobile-borne observing system on 3 May 1999. The “mobile mesonet” observed relatively warm and moist air, weak baroclinity, and small pressure excess at the surface within the rear-flank downdrafts of the storms. Furthermore, the downdraft air parcels, which have been shown to enter the tornado in past observational and modeling studies, were associated with substantial convective available potential energy and small convective inhibition. The detection of only small equivalent potential temperature deficits (1–4 K) within the downdrafts may imply that the downdrafts were driven primarily by nonhydrostatic pressure gradients and/or precipitation drag, rather than by the entrainment of potentially cold environmental air at midlevels.

Corresponding author address: Dr. Paul Markowski, The Pennsylvania State University, 503 Walker Building, University Park, PA 16802. Email: marko@mail.meteo.psu.edu

Abstract

Two long-lived tornadic supercells were sampled by an automobile-borne observing system on 3 May 1999. The “mobile mesonet” observed relatively warm and moist air, weak baroclinity, and small pressure excess at the surface within the rear-flank downdrafts of the storms. Furthermore, the downdraft air parcels, which have been shown to enter the tornado in past observational and modeling studies, were associated with substantial convective available potential energy and small convective inhibition. The detection of only small equivalent potential temperature deficits (1–4 K) within the downdrafts may imply that the downdrafts were driven primarily by nonhydrostatic pressure gradients and/or precipitation drag, rather than by the entrainment of potentially cold environmental air at midlevels.

Corresponding author address: Dr. Paul Markowski, The Pennsylvania State University, 503 Walker Building, University Park, PA 16802. Email: marko@mail.meteo.psu.edu

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  • Adlerman, E. J., Droegemeier K. K. , and Davies-Jones R. P. , 1999: A numerical simulation of cyclic mesocyclogenesis. J. Atmos. Sci., 56 , 20452069.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Barnes, S. L., 1978: Oklahoma thunderstorms on 29–30 April 1970. Part I: Morphology of a tornadic storm. Mon. Wea. Rev., 106 , 673684.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Bluestein, H. B., 1983: Surface meteorological observations in severe thunderstorms. Part II: Field experiments with TOTO. J. Climate Appl. Meteor., 22 , 919930.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Brandes, E. A., 1977: Gust front evolution and tornado genesis as viewed by Doppler radar. J. Appl. Meteor., 16 , 333338.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Brandes, E. A., . 1978: Mesocyclone evolution and tornadogenesis: Some observations. Mon. Wea. Rev., 106 , 9951011.

  • Brandes, E. A., . 1981: Finestructure of the Del City-Edmond tornadic mesocirculation. Mon. Wea. Rev., 109 , 635647.

  • Brock, F. V., Crawford K. , Elliot R. , Cupernus G. , Stadler S. , Johnson H. , and Eilts M. , 1995: The Oklahoma Mesonet: A technical overview. J. Atmos. Oceanic Technol., 12 , 519.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Brooks, H. E., Doswell III C. A. , and Davies-Jones R. P. , 1993: Environmental helicity and the maintenance and evolution of low-level mesocyclones. The Tornado: Its Structure, Dynamics, Prediction, and Hazards, Geophys. Monogr., No. 79, Amer. Geophys. Union, 97–104.

    • Search Google Scholar
    • Export Citation
  • Browning, K. A., and Ludlam F. H. , 1962: Airflow in convective storms. Quart. J. Roy. Meteor. Soc., 88 , 117135.

  • Browning, K. A., and Donaldson R. J. , 1963: Airflow and structure of a tornadic storm. J. Atmos. Sci., 20 , 533545.

  • Burgess, D. W., Brown R. A. , Lemon L. R. , and Safford C. R. , 1977: Evolution of a tornadic thunderstorm. Preprints, 10th Conf. on Severe Local Storms, Omaha, NE, Amer. Meteor. Soc., 84–89.

    • Search Google Scholar
    • Export Citation
  • Charba, J., and Sasaki Y. , 1971: Structure and movement of the severe thunderstorms of 3 April 1964 as revealed from radar and surface mesonetwork data analysis. J. Meteor. Soc. Japan, 49 , 191214.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Davies-Jones, R. P., 1982: A new look at the vorticity equation with application to tornadogenesis. Preprints, 12th Conf. on Severe Local Storms, San Antonio, TX, Amer. Meteor. Soc., 249–252.

    • Search Google Scholar
    • Export Citation
  • Davies-Jones, R. P., . 1986: Tornado dynamics. Thunderstorm Morphology and Dynamics, E. Kessler, Ed., 2d ed., University of Oklahoma Press, 197–236.

    • Search Google Scholar
    • Export Citation
  • Davies-Jones, R. P., and Brooks H. E. , 1993: Mesocyclogenesis from a theoretical perspective. The Tornado: Its Structure, Dynamics, Prediction, and Hazards, Geophys. Monogr., No. 79, Amer. Geophys. Union, 105–114.

    • Search Google Scholar
    • Export Citation
  • Fujita, T. T., 1955: Results of detailed synoptic studies of squall lines. Tellus, 4 , 405436.

  • Fujita, T. T., . 1958: Tornado cyclone: Bearing system of tornadoes. Proc. Seventh Conf. on Radar Meteorology, Miami Beach, FL, Amer. Meteor. Soc., K31–K38.

    • Search Google Scholar
    • Export Citation
  • Fujita, T. T., . 1975: New evidence from the April 3–4, 1974 tornadoes. Preprints, Ninth Conf. on Severe Local Storms, Norman, OK, Amer. Meteor. Soc., 248–255.

    • Search Google Scholar
    • Export Citation
  • Fujita, T. T., and Wakimoto R. M. , 1982: Anticyclonic tornadoes in 1980 and 1981. Preprints, 12th Conf. on Severe Local Storms, San Antonio, TX, Amer. Meteor. Soc., 213–216.

    • Search Google Scholar
    • Export Citation
  • Golden, J. H., and Morgan B. J. , 1972: The NSSL/Notre Dame tornado intercept program, spring 1972. Bull. Amer. Meteor. Soc., 53 , 11781179.

    • Search Google Scholar
    • Export Citation
  • Jensen, B., Marshall T. P. , Mabey M. A. , and Rasmussen E. N. , 1983: Storm scale structure of the Pampa storm. Preprints, 13th Conf. on Severe Local Storms, Tulsa, OK, Amer. Meteor. Soc., 85–88.

    • Search Google Scholar
    • Export Citation
  • Lemon, L. R., and Doswell C. A. , 1979: Severe thunderstorm evolution and mesocyclone structure as related to tornadogenesis. Mon. Wea. Rev., 107 , 11841197.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Markowski, P. M., 2000: Surface thermodynamic characteristics of rear-flank downdrafts, with implications for tornado genesis and maintenance. Ph.D. dissertation, University of Oklahoma, 217 pp. [Available from Bell and Howell Information and Learning, Ann Arbor, MI 48106-1346.].

    • Search Google Scholar
    • Export Citation
  • Rasmussen, E. N., Peterson R. E. , Minor J. E. , and Campbell B. D. , 1982: Evolutionary characteristics and photogrammetric determination of windspeeds within the Tulia outbreak tornadoes 28 May 1980. Preprints, 12th Conf. on Severe Local Storms, San Antonio, TX, Amer. Meteor. Soc., 301–304.

    • Search Google Scholar
    • Export Citation
  • Rasmussen, E. N., Straka J. M. , Davies-Jones R. P. , Doswell C. A. , Carr F. H. , Eilts M. D. , and MacGorman D. R. , 1994: Verification of the Origins of Rotation in Tornadoes Experiment: VORTEX. Bull. Amer. Meteor. Soc., 75 , 9951006.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Ray, P. S., Doviak R. J. , Walker G. B. , Sirmans D. , Carter J. , and Bumgarner B. , 1975: Dual-Doppler observation of a tornadic storm. J. Appl. Meteor., 14 , 15211530.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Ray, P. S., Johnson B. C. , Johnson K. W. , Bradberry J. S. , Stephens J. J. , Wagner K. K. , Wilhelmson R. B. , and Klemp J. B. , 1981: The morphology of several tornadic storms on 20 May 1977. J. Atmos. Sci., 38 , 16431663.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Rutledge, S. A., and Hobbs P. V. , 1984: The mesoscale and microscale structure and organization of clouds and precipitation in midlatitude cyclones. Part XII: A diagnostic modeling study of precipitation development in narrow cold-frontal rainbands. J. Atmos. Sci., 41 , 29492972.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Straka, J. M., Rasmussen E. N. , and Fredrickson S. E. , 1996: A mobile mesonet for finescale meteorological observations. J. Atmos. Oceanic Technol., 13 , 921936.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Tepper, M., and Eggert W. E. , 1956: Tornado proximity traces. Bull. Amer. Meteor. Soc., 37 , 152159.

  • Walko, R. L., 1993: Tornado spin-up beneath a convective cell: Required basic structure of the near-field boundary layer winds. The Tornado: Its Structure, Dynamics, Prediction, and Hazards, Geophys. Monogr., No. 79, Amer. Geophys. Union, 89–95.

    • Search Google Scholar
    • Export Citation
  • Wicker, L. J., and Wilhelmson R. B. , 1995: Simulation and analysis of tornado development and decay within a three-dimensional supercell thunderstorm. J. Atmos. Sci., 52 , 26752703.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wurman, J., Straka J. M. , and Rasmussen E. N. , 1996: Fine-scale Doppler radar observations of tornadic storms. Science, 272 , 17741777.

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