Editorial Type:
Article
Article Type:
Research Article

Composite VORTEX2 Supercell Environments from Near-Storm Soundings

Matthew D. Parker Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, North Carolina

Search for other papers by Matthew D. Parker in
Current site
Google Scholar
PubMed Close
Print Publication:
01 Feb 2014
DOI:
https://doi.org/10.1175/MWR-D-13-00167.1
Page(s):
508–529
Restricted access

Abstract

Three-dimensional composite analyses using 134 soundings from the second Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX2) reveal the nature of near-storm variability in the environments of supercell thunderstorms. Based upon the full analysis, it appears that vertical wind shear increases as one approaches a supercell within the inflow sector, providing favorable conditions for supercell maintenance (and possibly tornado formation) despite small amounts of low-level cooling near the storm. The seven analyzed tornadic supercells have a composite environment that is clearly more impressive (in terms of widely used metrics) than that of the five analyzed nontornadic supercells, including more convective available potential energy (CAPE), more vertical wind shear, higher boundary layer relative humidity, and lower tropospheric horizontal vorticity that is more streamwise in the near-storm inflow. The widely used supercell composite parameter (SCP) and significant tornado parameter (STP) summarize these differences well. Comparison of composite environments from early versus late in supercells' lifetimes reveals only subtle signs of storm-induced environmental modification, but potentially important changes associated with the evening transition toward a cooler and moister boundary layer with enhanced low-level vertical shear. Finally, although this study focused primarily on the composite inflow environment, it is intriguing that the outflows sampled by VORTEX2 soundings were surprisingly shallow (generally ≤500 m deep) and retained considerable CAPE (generally ≥1000 J kg−1). The numerous VORTEX2 near-storm soundings provide an unprecedented observational view of supercell–environment interactions, and the analyses are ripe for use in a variety of future studies.

Corresponding author address: Matthew D. Parker, North Carolina State University, Campus Box 8208, Raleigh, NC 27615-8208. E-mail: mdparker@ncsu.edu

Abstract

Three-dimensional composite analyses using 134 soundings from the second Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX2) reveal the nature of near-storm variability in the environments of supercell thunderstorms. Based upon the full analysis, it appears that vertical wind shear increases as one approaches a supercell within the inflow sector, providing favorable conditions for supercell maintenance (and possibly tornado formation) despite small amounts of low-level cooling near the storm. The seven analyzed tornadic supercells have a composite environment that is clearly more impressive (in terms of widely used metrics) than that of the five analyzed nontornadic supercells, including more convective available potential energy (CAPE), more vertical wind shear, higher boundary layer relative humidity, and lower tropospheric horizontal vorticity that is more streamwise in the near-storm inflow. The widely used supercell composite parameter (SCP) and significant tornado parameter (STP) summarize these differences well. Comparison of composite environments from early versus late in supercells' lifetimes reveals only subtle signs of storm-induced environmental modification, but potentially important changes associated with the evening transition toward a cooler and moister boundary layer with enhanced low-level vertical shear. Finally, although this study focused primarily on the composite inflow environment, it is intriguing that the outflows sampled by VORTEX2 soundings were surprisingly shallow (generally ≤500 m deep) and retained considerable CAPE (generally ≥1000 J kg−1). The numerous VORTEX2 near-storm soundings provide an unprecedented observational view of supercell–environment interactions, and the analyses are ripe for use in a variety of future studies.

Corresponding author address: Matthew D. Parker, North Carolina State University, Campus Box 8208, Raleigh, NC 27615-8208. E-mail: mdparker@ncsu.edu
Save
Cover Monthly Weather Review
Monthly Weather Review

  • Barnes, S. L., 1973: Mesoscale objective analysis using weighted time-series observations. NOAA Tech. Memo. ERL NSSL-62, 60 pp. [Available from National Severe Storms Laboratory, Norman, OK 73069.]

  • Beck, J., and C. Weiss, 2013: An assessment of low-level baroclinity and vorticity within a simulated supercell. Mon. Wea. Rev., 141, 649–669.

    • Search Google Scholar
    • Export Citation

  • Benjamin, S. G., G. A. Grell, J. M. Brown, T. G. Smirnova, and R. Bleck, 2004: Mesoscale weather prediction with the RUC hybrid isentropic–terrain-following coordinate model. Mon. Wea. Rev., 132, 473–494.

    • Search Google Scholar
    • Export Citation

  • Blackadar, A. K., 1957: Boundary layer wind maxima and their significance for the growth of nocturnal inversions. Bull. Amer. Meteor. Soc., 38, 282–290.

    • Search Google Scholar
    • Export Citation

  • Brooks, H. E., C. A. Doswell III, and J. Cooper, 1994: On the environments of tornadic and nontornadic mesocyclones. Wea. Forecasting, 9, 606–618.

    • Search Google Scholar
    • Export Citation

  • Bryan, G. H., and M. D. Parker, 2010: Observations of a squall line and its near environment using high-frequency rawinsonde launches during VORTEX2. Mon. Wea. Rev., 138, 4076–4097.

    • Search Google Scholar
    • Export Citation

  • Coniglio, M. C., 2012: Verification of RUC 0–1-h forecasts and SPC mesoscale analyses using VORTEX2 soundings. Wea. Forecasting, 27, 667–683.

    • 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, 1593–1616.

    • Search Google Scholar
    • Export Citation

  • Davies-Jones, R., 1984: Streamwise vorticity: The origin of updraft rotation in supercell storms. J. Atmos. Sci., 41, 2991–3006.

  • Dawson, D. T., M. Xue, J. A. Milbrandt, and M. K. Yau, 2010: Comparison of evaporation and cold pool development between single-moment and multimoment bulk microphysics schemes in idealized simulations of tornadic thunderstorms. Mon. Wea. Rev., 138, 1152–1171.

    • Search Google Scholar
    • Export Citation

  • Frame, J., and P. Markowski, 2010: Numerical simulations of radiative cooling beneath the anvils of supercell thunderstorms. Mon. Wea. Rev., 138, 3024–3047.

    • Search Google Scholar
    • Export Citation

  • Gal-Chen, T., and R. Somerville, 1975: On the use of a coordinate transformation for the solution of the Navier–Stokes equations. J. Comput. Phys., 17, 209–228.

    • Search Google Scholar
    • Export Citation

  • Grzych, M. L., B. D. Lee, and C. A. Finley, 2007: Thermodynamic analysis of supercell rear-flank downdrafts from Project ANSWERS. Mon. Wea. Rev., 135, 240–246.

    • Search Google Scholar
    • Export Citation

  • Klemp, J. B., and R. Rotunno, 1983: A study of the tornadic region within a supercell thunderstorm. J. Atmos. Sci., 40, 359–377.

  • Koch, S. E., M. DesJardins, and P. J. Kocin, 1983: An interactive Barnes objective map analysis scheme for use with satellite and conventional data. J. Climate Appl. Meteor., 22, 1487–1503.

    • Search Google Scholar
    • Export Citation

  • Letkewicz, C. E., A. J. French, and M. D. Parker, 2013: Base-state substitution: An idealized modeling technique for approximating environmental variability. Mon. Wea. Rev., 141, 3062–3086.

    • Search Google Scholar
    • Export Citation

  • Loehrer, S. M., T. A. Edmands, and J. A. Moore, 1996: TOGA COARE upper-air sounding data archive: Development and quality control procedures. Bull. Amer. Meteor. Soc., 77, 2651–2671.

    • Search Google Scholar
    • Export Citation

  • Loehrer, S. M., S. F. Williams, and J. A. Moore, 1998: Results from UCAR/JOSS quality control of atmospheric soundings from field projects. Preprints, 10th Symp. on Meteorological Observations and Instrumentation, Phoenix, AZ, Amer. Meteor. Soc., 1–6.

  • Maddox, R. A., 1993: Diurnal low-level wind oscillation and storm-relative helicity. The Tornado: Its Structure, Dynamics, Prediction, and Hazards, Geophys. Monogr., Vol. 79, Amer. Geophys. Union, 591–598.

  • Markowski, P. M., and Y. P. Richardson, 2014: The influence of environmental low-level shear and cold pools on tornadogenesis: Insights from idealized simulations. J. Atmos. Sci., in press.

    • Search Google Scholar
    • Export Citation

  • Markowski, P. M., E. N. Rasmussen, J. M. Straka, and D. C. Dowell, 1998a: Observations of low-level baroclinity generated by anvil shadows. Mon. Wea. Rev., 126, 2942–2958.

    • Search Google Scholar
    • Export Citation

  • Markowski, P. M., J. M. Straka, E. N. Rasmussen, and D. O. Blanchard, 1998b: Variability of storm-relative helicity during VORTEX. Mon. Wea. Rev., 126, 2959–2971.

    • Search Google Scholar
    • Export Citation

  • Markowski, P. M., J. M. Straka, and E. N. Rasmussen, 2002: Direct surface thermodynamic observations within the rear-flank downdrafts of nontornadic and tornadic supercells. Mon. Wea. Rev., 130, 1692–1721.

    • 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, 1262–1272.

    • Search Google Scholar
    • Export Citation

  • Morrison, H., and J. Milbrandt, 2011: Comparison of two-moment bulk microphysics schemes in idealized supercell thunderstorm simulations. Mon. Wea. Rev., 139, 1103–1130.

    • Search Google Scholar
    • Export Citation

  • Parker, M. D., and J. M. L. Dahl, 2013: Toy model simulations of surface vorticity generation in downdrafts. Extended Abstracts, 15th Conf. on Mesoscale Processes, Portland, OR, Amer. Meteor. Soc., 12.3. [Available online at https://ams.confex.com/ams/15MESO/webprogram/Paper227679.html.]

  • Pauley, P. M., and X. Wu, 1990: The theoretical, discrete, and actual response of the Barnes objective analysis scheme for one- and two-dimensional fields. Mon. Wea. Rev., 118, 1145–1164.

    • Search Google Scholar
    • Export Citation

  • Potvin, C. K., K. L. Elmore, and S. J. Weiss, 2010: Assessing the impacts of proximity sounding criteria on the climatology of significant tornado environments. Wea. Forecasting, 25, 921–930.

    • 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, 1148–1164.

    • Search Google Scholar
    • Export Citation

  • Richardson, Y. P., K. K. Droegemeier, and R. P. Davies-Jones, 2007: The influence of horizontal environmental variability on numerically simulated convective storms. Part I: Variations in vertical shear. Mon. Wea. Rev., 135, 3429–3455.

    • Search Google Scholar
    • Export Citation

  • Rotunno, R., and J. Klemp, 1985: On the rotation and propagation of simulated supercell thunderstorms. J. Atmos. Sci., 42, 271–292.

  • Shabbott, C. J., and P. M. Markowski, 2006: Surface in situ observations within the outflow of forward-flank downdrafts of supercell thunderstorms. Mon. Wea. Rev., 134, 1422–1441.

    • Search Google Scholar
    • Export Citation

  • Snook, N., and M. Xue, 2008: Effects of microphysical drop size distribution on tornadogenesis in supercell thunderstorms. Geophys. Res. Lett., 35, L24803, doi:10.1029/2008GL035866.

    • Search Google Scholar
    • Export Citation

  • Thompson, R. L., R. Edwards, J. A. Hart, K. L. Elmore, and P. M. Markowski, 2003: Close proximity soundings within supercell environments obtained from the Rapid Update Cycle. Wea. Forecasting, 18, 1243–1261.

    • Search Google Scholar
    • Export Citation

  • Thompson, R. L., R. Edwards, and C. M. Mead, 2004: An update to the supercell composite and significant tornado parameters. Preprints, 22nd Conf. on Severe Local Storms, Hyannis, MA, Amer. Meteor. Soc., P8.1. [Available online at http://ams.confex.com/ams/pdfpapers/82100.pdf.]

  • Thompson, R. L., C. M. Mead, and R. Edwards, 2007: Effective storm-relative helicity and bulk shear in supercell thunderstorm environments. Wea. Forecasting, 22, 102–115.

    • Search Google Scholar
    • Export Citation

  • Thompson, R. L., B. T. Smith, J. S. Grams, A. R. Dean, and C. Broyles, 2012: Convective modes for significant severe thunderstorms in the contiguous United States. Part II: Supercell and QLCS tornado environments. Wea. Forecasting, 27, 1136–1154.

    • Search Google Scholar
    • Export Citation

  • Trier, S. B., C. A. Davis, and J. D. Tuttle, 2000: Long-lived mesoconvective vortices and their environment. Part I: Observations from the central United States during the 1998 warm season. Mon. Wea. Rev., 128, 3376–3395.

    • 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, 2479–2498.

    • Search Google Scholar
    • Export Citation

  • Weisman, M. L., and R. Rotunno, 2000: The use of vertical wind shear versus helicity in interpreting supercell dynamics. J. Atmos. Sci., 57, 1452–1472.

    • Search Google Scholar
    • Export Citation

  • Wurman, J., D. Dowell, Y. Richardson, P. Markowski, E. Rasmussen, D. Burgess, L. Wicker, and H. B. Bluestein, 2012: The Second Verification of the Origins of Rotation in Tornadoes Experiment: VORTEX2. Bull. Amer. Meteor. Soc., 93, 1147–1170.

    • Search Google Scholar
    • Export Citation

  • Ziegler, C. L., 2013: A diabatic Lagrangian technique for the analysis of convective storms. Part II: Application to a radar-observed storm. J. Atmos. Oceanic Technol., 30, 2266–2280.

    • Search Google Scholar
    • Export Citation

  • Ziegler, C. L., E. R. Mansell, J. M. Straka, D. R. MacGorman, and D. W. Burgess, 2010: The impact of spatial variations of low-level stability on the lifecycle of a simulated supercell storm. Mon. Wea. Rev., 138, 1738–1766.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 964 383 36
PDF Downloads 740 244 20