• Atkins, N. T., M. L. Weisman, and L. J. Wicker, 1999: The influence of preexisting boundaries on supercell evolution. Mon. Wea. Rev., 127 , 29102927.

    • Search Google Scholar
    • Export Citation
  • Bryan, G. H., 2005: Spurious convective organization in simulated squall lines owing to moist absolutely unstable layers. Mon. Wea. Rev., 133 , 19781997.

    • Search Google Scholar
    • Export Citation
  • Bryan, G. H., J. C. Wyngaard, and J. M. Fritsch, 2003: Resolution requirements for the simulation of deep moist convection. Mon. Wea. Rev., 131 , 23942416.

    • Search Google Scholar
    • Export Citation
  • Burgess, D. W., and E. B. Curran, 1985: The relationship of storm type to environment in Oklahoma on 26 April 1984. Preprints, 14th Conf. on Severe Local Storms, Indianapolis, IN, Amer. Meteor. Soc., 208–211.

  • Carpenter, K. M., 1982: Note on the paper “Radiation conditions for the lateral boundaries of limited-area numerical models” by M. J. Miller and A. J. Thorpe. Quart. J. Roy. Meteor. Soc., 108 , 717719.

    • Search Google Scholar
    • Export Citation
  • Coniglio, M. C., and D. J. Stensrud, 2001: Simulation of a progressive derecho using composite initial conditions. Mon. Wea. Rev., 129 , 15931616.

    • Search Google Scholar
    • Export Citation
  • Crook, N. A., and M. W. Moncrieff, 1988: The effect of large-scale convergence on the generation and maintenance of deep moist convection. J. Atmos. Sci., 45 , 36063624.

    • Search Google Scholar
    • Export Citation
  • Davies-Jones, R., 1984: Streamwise vorticity: The origin of updraft rotation in supercell storms. J. Atmos. Sci., 41 , 29913006.

  • Deardorff, J. W., 1980: Stratocumulus-capped mixed layers derived from a three-dimensional model. Bound.-Layer Meteor., 18, 495–527.

  • Droegemeier, K. K., 1997: The numerical prediction of thunderstorms: Challenges, potential benefits, and results from realtime operational tests. WMO Bull., 46 , 324336.

    • Search Google Scholar
    • Export Citation
  • Evans, J. S., and C. A. Doswell III, 2001: Examination of derecho environments using proximity soundings. Wea. Forecasting, 16 , 329342.

    • Search Google Scholar
    • Export Citation
  • Johns, R. H., and W. D. Hirt, 1987: Derechos: Widespread convectively induced windstorms. Wea. Forecasting, 2 , 3249.

  • Kay, M. P., and L. J. Wicker, 1998: Numerical simulations of supercell interactions with thermal boundaries. Preprints, 19th Conf. on Severe Local Storms, Minneapolis, MN, Amer. Meteor. Soc., 246–248.

  • Klemp, J. B., and R. B. Wilhelmson, 1978a: The simulation of three-dimensional convective storm dynamics. J. Atmos. Sci., 35 , 10701096.

    • Search Google Scholar
    • Export Citation
  • Klemp, J. B., and R. B. Wilhelmson, 1978b: The simulation of right- and left-moving storms produced through storm splitting. J. Atmos. Sci., 35 , 10971110.

    • Search Google Scholar
    • Export Citation
  • Kost, J., and Y. P. Richardson, 2004: The influence of temporally-varying vertical wind shear on numerically simulated convective storms. Preprints, 22d Conf. on Severe Local Storms, Hyannis, MA, Amer. Meteor. Soc., CD-ROM, 9.2.

  • Kron, J., 2004: The evolution of numerically-modeled convection in an environment containing horizontal variations of vertical shear and low-level moisture. M.S. thesis, Dept. of Meteorology, The Pennsylvania State University, 170 pp.

  • Lilly, D. K., 1986a: The structure, energetics and propagation of rotating convective storms. Part I: Energy exchange with the mean flow. J. Atmos. Sci., 43 , 113125.

    • Search Google Scholar
    • Export Citation
  • Lilly, D. K., 1986b: The structure, energetics and propagation of rotating convective storms. Part II: Helicity and storm stabilization. J. Atmos. Sci., 43 , 126140.

    • Search Google Scholar
    • Export Citation
  • Markowski, P. M., and Y. P. Richardson, 2007: Observations of vertical wind shear heterogeneity in convective boundary layers. Mon. Wea. Rev., 135 , 843861.

    • Search Google Scholar
    • Export Citation
  • Markowski, P. M., J. M. Straka, E. N. Rasmussen, and D. O. Blanchard, 1998: Variability of storm-relative helicity during VORTEX. Mon. Wea. Rev., 126 , 29592971.

    • Search Google Scholar
    • Export Citation
  • Markowski, P. M., C. Hannon, J. Frame, E. Lancaster, A. Pietrycha, R. Edwards, and R. L. Thompson, 2003: Characteristics of vertical wind profiles near supercells obtained from the Rapid Update Cycle. Wea. Forecasting, 18 , 12621272.

    • Search Google Scholar
    • Export Citation
  • Marwitz, J. D., 1972a: The structure and motion of severe hailstorms. Part I: Supercell storms. J. Appl. Meteor., 11 , 166179.

  • Marwitz, J. D., 1972b: The structure and motion of severe hailstorms. Part II: Multicell storms. J. Appl. Meteor., 11 , 180188.

  • Marwitz, J. D., 1972c: The structure and motion of severe hailstorms. Part III: Severely sheared storms. J. Appl. Meteor., 11 , 189201.

    • Search Google Scholar
    • Export Citation
  • McCaul, E. W., and M. L. Weisman, 2001: The sensitivity of simulated supercell structure and intensity to variations in the shapes of environmental buoyancy and shear profiles. Mon. Wea. Rev., 129 , 664687.

    • Search Google Scholar
    • Export Citation
  • Moeng, C. H., 1984: A large-eddy simulation model for the study of planetary boundary-layer turbulence. J. Atmos. Sci., 41 , 20522062.

    • Search Google Scholar
    • Export Citation
  • Moeng, C. H., and J. C. Wyngaard, 1988: Spectral analysis of large-eddy simulations of the convective boundary layer. J. Atmos. Sci., 45 , 35733587.

    • Search Google Scholar
    • Export Citation
  • Moncrieff, M. W., and J. S. A. Green, 1972: The propagation and transfer properties of steady convective-overturning in shear. Quart. J. Roy. Meteor. Soc., 98 , 336352.

    • Search Google Scholar
    • Export Citation
  • Rasmussen, E. N., and D. O. Blanchard, 1998: A baseline climatology of sounding-derived supercell and tornado forecast parameters. Wea. Forecasting, 13 , 11481164.

    • Search Google Scholar
    • Export Citation
  • Richardson, Y. P., 1999: The influence of horizontal variations in vertical shear and low-level moisture on numerically simulated convective storms. Ph.D. dissertation, School of Meteorology, University of Oklahoma, 236 pp.

  • Rotunno, R., and J. B. Klemp, 1982: The influence of the shear-induced pressure gradient on thunderstorm motion. Mon. Wea. Rev., 110 , 136151.

    • Search Google Scholar
    • Export Citation
  • Rotunno, R., and J. B. Klemp, 1985: On the rotation and propagation of simulated supercell thunderstorms. J. Atmos. Sci., 42 , 271292.

    • Search Google Scholar
    • Export Citation
  • Rotunno, R., J. B. Klemp, and M. L. Weisman, 1988: A theory for strong, long-lived squall lines. J. Atmos. Sci., 45 , 463485.

  • Skamarock, W. C., M. L. Weisman, C. A. Davis, and J. B. Klemp, 1994: The evolution of simulated mesoscale convective systems in idealized environments. Preprints, Sixth Conf. on Mesoscale Meteorology, Portland, OR, Amer. Meteor. Soc., 407–410.

  • Stensrud, D. J., M. C. Coniglio, R. P. Davies-Jones, and J. S. Evans, 2005: Comments on “‘A theory for strong long-lived squall lines’ revisited.”. J. Atmos. Sci., 62 , 29892996.

    • Search Google Scholar
    • Export Citation
  • Weisman, M. L., 1993: The genesis of severe, long-lived bow echoes. J. Atmos. Sci., 50 , 645670.

  • 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 , 504520.

    • Search Google Scholar
    • Export Citation
  • Weisman, M. L., and J. B. Klemp, 1984: The structure and classification of numerically simulated convective storms in directionally varying wind shears. Mon. Wea. Rev., 112 , 24792498.

    • Search Google Scholar
    • Export Citation
  • Weisman, M. L., and R. Rotunno, 2004: “A theory for strong long-lived squall lines” revisited. J. Atmos. Sci., 61 , 361382.

  • Weisman, M. L., and R. Rotunno, 2005: Reply. J. Atmos. Sci., 62 , 29973002.

  • Weisman, M. L., J. B. Klemp, and R. Rotunno, 1988: Structure and evolution of numerically simulated squall lines. J. Atmos. Sci., 45 , 19902013.

    • Search Google Scholar
    • Export Citation
  • Weisman, M. L., 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.

  • Xue, M., V. Wong, A. Shapiro, and K. Brewster, 1995: ARPS version 4.0 user’s guide. Center for Analysis and Prediction of Storms, University of Oklahoma, Norman, OK, 380 pp.

  • Xue, M., K. K. Droegemeier, and V. Wong, 2000: The Advanced Regional Prediction System (ARPS)—A multiscale nonhydrostatic atmospheric simulation and prediction tool. Part I: Model dynamics and verification. Meteor. Atmos. Phys., 75 , 161193.

    • Search Google Scholar
    • Export Citation
  • Xue, M., and Coauthors, 2001: The Advanced Regional Prediction System (ARPS)—A multiscale nonhydrostatic atmospheric simulation and prediction tool. Part II: Model physics and applications. Meteor. Atmos. Phys., 76 , 143165.

    • Search Google Scholar
    • Export Citation
  • Xue, M., D-H. Wang, J-D. Gao, K. Brewster, and K. K. Droegemeier, 2003: The Advanced Regional Prediction System (ARPS), storm-scale numerical weather prediction and data assimilation. Meteor. Atmos. Phys., 82 , 139170.

    • Search Google Scholar
    • Export Citation
  • Zalesak, S. T., 1979: Fully multidimensional flux-corrected transport algorithms for fluids. J. Comput. Phys., 31 , 335362.

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The Influence of Horizontal Environmental Variability on Numerically Simulated Convective Storms. Part I: Variations in Vertical Shear

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  • 1 School of Meteorology, and Center for Analysis and Prediction of Storms, University of Oklahoma, Norman, Oklahoma
  • | 2 National Severe Storms Laboratory, Norman, Oklahoma
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Abstract

Severe convective storms are typically simulated using either an idealized, horizontally homogeneous environment (i.e., single sounding) or an inhomogeneous environment constructed using numerous types of observations. Representing opposite ends of the spectrum, the former allows for the study of storm dynamics without the complicating effects of either land surface or atmospheric variability, though arguably at the expense of physical realism, while the latter is especially useful for prediction and data sensitivity studies, though because of its physical completeness, determination of cause can be extremely difficult. In this study, the gap between these two extremes is bridged by specifying horizontal variations in environmental vertical shear in an idealized, controlled manner so that their influence on storm morphology can be readily diagnosed. Simulations are performed using the Advanced Regional Prediction System (ARPS), though with significant modification to accommodate the analytically specified environmental fields. Several steady-state environments are constructed herein that retain a good degree of physical realism while permitting clear interpretation of cause and effect. These experiments are compared to counterpart control simulations in homogeneous environments constructed using single wind profiles from selected locations within the inhomogeneous environment domain. Simulations in which steady-state vertical shear varies spatially are presented for different shear regimes (storm types). A gradient of weak shear across the storm system leads to preferred cell development on the flank with greater shear. In a stronger shear regime (i.e., in the borderline multicell/supercell regime), however, cell development is enhanced on the weaker shear flank while cell organization is enhanced on the strong shear side. When an entire storm system moves from weak to strong shear, changes in cell structure are influenced by local mesoscale forcing associated with the cold pool. In this particular experiment, cells near the leading edge of the cold pool, where gust front convergence occurs along a continuous line, evolve into a bow-echo structure as the shear increases. In contrast, simulated cells that remain relatively isolated on the flank of the cold pool tend to develop supercellular characteristics.

* Current affiliation: Department of Meteorology, The Pennsylvania State University, University Park, Pennsylvania

Corresponding author address: Dr. Yvette P. Richardson, Department of Meteorology, The Pennsylvania State University, 503 Walker Building, University Park, PA 16802. Email: yrichardson@psu.edu

Abstract

Severe convective storms are typically simulated using either an idealized, horizontally homogeneous environment (i.e., single sounding) or an inhomogeneous environment constructed using numerous types of observations. Representing opposite ends of the spectrum, the former allows for the study of storm dynamics without the complicating effects of either land surface or atmospheric variability, though arguably at the expense of physical realism, while the latter is especially useful for prediction and data sensitivity studies, though because of its physical completeness, determination of cause can be extremely difficult. In this study, the gap between these two extremes is bridged by specifying horizontal variations in environmental vertical shear in an idealized, controlled manner so that their influence on storm morphology can be readily diagnosed. Simulations are performed using the Advanced Regional Prediction System (ARPS), though with significant modification to accommodate the analytically specified environmental fields. Several steady-state environments are constructed herein that retain a good degree of physical realism while permitting clear interpretation of cause and effect. These experiments are compared to counterpart control simulations in homogeneous environments constructed using single wind profiles from selected locations within the inhomogeneous environment domain. Simulations in which steady-state vertical shear varies spatially are presented for different shear regimes (storm types). A gradient of weak shear across the storm system leads to preferred cell development on the flank with greater shear. In a stronger shear regime (i.e., in the borderline multicell/supercell regime), however, cell development is enhanced on the weaker shear flank while cell organization is enhanced on the strong shear side. When an entire storm system moves from weak to strong shear, changes in cell structure are influenced by local mesoscale forcing associated with the cold pool. In this particular experiment, cells near the leading edge of the cold pool, where gust front convergence occurs along a continuous line, evolve into a bow-echo structure as the shear increases. In contrast, simulated cells that remain relatively isolated on the flank of the cold pool tend to develop supercellular characteristics.

* Current affiliation: Department of Meteorology, The Pennsylvania State University, University Park, Pennsylvania

Corresponding author address: Dr. Yvette P. Richardson, Department of Meteorology, The Pennsylvania State University, 503 Walker Building, University Park, PA 16802. Email: yrichardson@psu.edu

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