Editorial Type:
Article
Article Type:
Research Article

The LaGrange Tornado during VORTEX2. Part II: Photogrammetric Analysis of the Tornado Combined with Dual-Doppler Radar Data

Nolan T. Atkins Department of Atmospheric Sciences, Lyndon State College, Lyndonville, Vermont

Search for other papers by Nolan T. Atkins in
Current site
Google Scholar
PubMed Close
,
Anthony McGee Department of Atmospheric Sciences, Lyndon State College, Lyndonville, Vermont

Search for other papers by Anthony McGee in
Current site
Google Scholar
PubMed Close
,
Rachel Ducharme Department of Atmospheric Sciences, Lyndon State College, Lyndonville, Vermont

Search for other papers by Rachel Ducharme in
Current site
Google Scholar
PubMed Close
,
Roger M. Wakimoto National Center for Atmospheric Research,* Boulder, Colorado

Search for other papers by Roger M. Wakimoto in
Current site
Google Scholar
PubMed Close
, and
Joshua Wurman Center for Severe Weather Research, Boulder, Colorado

Search for other papers by Joshua Wurman in
Current site
Google Scholar
PubMed Close
Print Publication:
01 Sep 2012
DOI:
https://doi.org/10.1175/MWR-D-11-00285.1
Page(s):
2939–2958
Restricted access

Abstract

This study presents the synthesis of dual-Doppler and cloud photography data of the 5 June 2009 Goshen County, Wyoming, tornado observed during the Second Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX2). Analyses focused on the hook region of the parent supercell. It will be shown that radar-determined tornadogenesis and initial surface wind damage occurred 14 min before the funnel cloud was observed continuously on the ground. In addition to the cyclonic wall cloud, an anticyclonic lowering was also observed on the southern flank of the hook echo near the time of tornadogenesis.

The relationship between the intensities of the tornado and its parent circulation, the low-level mesocyclone, will also be discussed. Funnel diameter was not well correlated with the maximum vertical vorticity or circulation associated with the mesocyclone. Furthermore, changes in the minimum reflectivity observed in the tornado-scale weak echo hole (WEH) were weakly correlated with the maximum vertical vorticity of the mesocyclone. The tornado funnel was observed within and was relatively small compared to the WEH diameter.

The distribution and evolution of angular momentum were also examined. The radial increase of angular momentum terminated at or beyond the wall cloud edge. Prior to the time that the funnel made continuous contact with the ground, low-level angular momentum increased despite the fact that azimuthally averaged low-level flow within the mesocyclone was divergent, advecting low angular momentum air away from the circulation center. Both the tornado and mesocyclone generally intensified during this time. Thereafter, while the tornado continued to intensify, angular momentum within the low-level mesocyclone weakened.

The National Center for Atmospheric Research is sponsored by the National Science Foundation.

Corresponding author address: Nolan T. Atkins, Department of Atmospheric Sciences, Lyndon State College, Lyndonville, VT 05851. E-mail: nolan.atkins@lyndonstate.edu

Abstract

This study presents the synthesis of dual-Doppler and cloud photography data of the 5 June 2009 Goshen County, Wyoming, tornado observed during the Second Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX2). Analyses focused on the hook region of the parent supercell. It will be shown that radar-determined tornadogenesis and initial surface wind damage occurred 14 min before the funnel cloud was observed continuously on the ground. In addition to the cyclonic wall cloud, an anticyclonic lowering was also observed on the southern flank of the hook echo near the time of tornadogenesis.

The relationship between the intensities of the tornado and its parent circulation, the low-level mesocyclone, will also be discussed. Funnel diameter was not well correlated with the maximum vertical vorticity or circulation associated with the mesocyclone. Furthermore, changes in the minimum reflectivity observed in the tornado-scale weak echo hole (WEH) were weakly correlated with the maximum vertical vorticity of the mesocyclone. The tornado funnel was observed within and was relatively small compared to the WEH diameter.

The distribution and evolution of angular momentum were also examined. The radial increase of angular momentum terminated at or beyond the wall cloud edge. Prior to the time that the funnel made continuous contact with the ground, low-level angular momentum increased despite the fact that azimuthally averaged low-level flow within the mesocyclone was divergent, advecting low angular momentum air away from the circulation center. Both the tornado and mesocyclone generally intensified during this time. Thereafter, while the tornado continued to intensify, angular momentum within the low-level mesocyclone weakened.

The National Center for Atmospheric Research is sponsored by the National Science Foundation.

Corresponding author address: Nolan T. Atkins, Department of Atmospheric Sciences, Lyndon State College, Lyndonville, VT 05851. E-mail: nolan.atkins@lyndonstate.edu
Save
Cover Monthly Weather Review
Monthly Weather Review

  • Agee, E. M., J. T. Snow, and P. R. Clare, 1976: Multiple vortex features in the tornado cyclone and the occurrence of tornado families. Mon. Wea. Rev., 104, 552–563.

    • Search Google Scholar
    • Export Citation

  • Alexander, C. R., and J. Wurman, 2005: The 30 May 1998 Spencer, South Dakota, storm. Part I: The evolution and environment of the tornadoes. Mon. Wea. Rev., 133, 72–96.

    • Search Google Scholar
    • Export Citation

  • Alexander, C. R., and J. Wurman, 2008: Updated mobile radar climatology of supercell tornado structures and dynamics. Preprints, 24th Conf. on Severe Local Storms, Savannah, GA, Amer. Meteor. Soc., 19.4. [Available online at http://ams.confex.com/ams/pdfpapers/141821.pdf.]

  • Beck, J. R., J. L. Schroeder, and J. M. Wurman, 2006: High-resolution dual-Doppler analyses of the 29 May 2001 Kress, Texas, cyclic supercell. Mon. Wea. Rev., 134, 3125–3148.

    • Search Google Scholar
    • Export Citation

  • Bluestein, H. B., 1993: Synoptic-Dynamic Meteorology in Midlatitudes. Vol. 2, Observations and Theory of Weather Systems, Oxford Press, 594 pp.

  • Bluestein, H. B., and W. P. Unruh, 1989: Observations of the wind field in tornadoes, funnel clouds, and wall clouds with a portable Doppler radar. Bull. Amer. Meteor. Soc., 70, 1514–1525.

    • Search Google Scholar
    • Export Citation

  • Bluestein, H. B., and A. L. Pazmany, 2000: Observations of tornadoes and other convective phenomena with a mobile, 3-mm wavelength, Doppler radar: The spring 1999 field experiment. Bull. Amer. Meteor. Soc., 81, 2939–2951.

    • Search Google Scholar
    • Export Citation

  • Bluestein, H. B., and S. G. Gaddy, 2001: Airborne pseudo-dual-Doppler analysis of a rear-inflow jet and deep convergence zone within a supercell. Mon. Wea. Rev., 129, 2270–2289.

    • Search Google Scholar
    • Export Citation

  • Bluestein, H. B., S. G. Gaddy, D. C. Dowell, A. L. Pazmany, J. C. Galloway, R. E. McIntosh, and H. Stein, 1997: Doppler radar observations of substorm-scale vortices in a supercell. Mon. Wea. Rev., 125, 1046–1059.

    • Search Google Scholar
    • Export Citation

  • Bluestein, H. B., C. C. Weiss, and A. L. Pazmany, 2003: Mobile Doppler radar observations of a tornado in a supercell near Bassett, Nebraska, on 5 June 1999. Part I: Tornadogenesis. Mon. Wea. Rev., 131, 2954–296.

    • Search Google Scholar
    • Export Citation

  • Bluestein, H. B., C. C. Weiss, and A. L. Pazmany, 2004: The vertical structure of a tornado near Happy, Texas, on 5 May 2002: High-resolution, mobile, W-band, Doppler radar observations. Mon. Wea. Rev., 132, 2325–2337.

    • Search Google Scholar
    • Export Citation

  • Bluestein, H. B., M. M. French, R. L. Tanamachi, S. Frasier, K. Hardwick, F. Junyent, and A. L. Pazmany, 2007a: Close-range observations of tornadoes in supercells made with a dual-polarization, X-band, mobile Doppler radar. Mon. Wea. Rev., 135, 1522–1543.

    • Search Google Scholar
    • Export Citation

  • Bluestein, H. B., C. C. Weiss, M. M. French, E. M. Holthaus, R. L. Tanamachi, S. Frasier, and A. L. Pazmany, 2007b: The structure of tornadoes near Attica, Kansas, on 12 May 2004: High-resolution, mobile, Doppler radar observations. Mon. Wea. Rev., 135, 475–506.

    • Search Google Scholar
    • Export Citation

  • Brandes, E. A., 1977: Gust front evolution and tornado genesis as viewed by Doppler radar. J. Appl. Meteor., 16, 333–338.

  • Brandes, E. A., 1978: Mesocyclone evolution and tornadogenesis: Some observations. Mon. Wea. Rev., 106, 995–1011.

  • Brandes, E. A., 1981: Finestructure of the Del City–Edmond tornadic mesocirculation. Mon. Wea. Rev., 109, 635–647.

  • Brandes, E. A., 1984: Vertical vorticity generation and mesoscyclone sustenance in tornadic thunderstorms: The observational evidence. Mon. Wea. Rev., 112, 2253–2269.

    • Search Google Scholar
    • Export Citation

  • Burgess, D., M. Magsig, J. Wurman, D. Dowell, and Y. Richardson, 2002: A detailed WSR-88D and DOW radar analysis of the Oklahoma City tornado of 3 May 1999. Wea. Forecasting, 17, 456–471.

    • Search Google Scholar
    • Export Citation

  • Davies-Jones, R. P., 1986: Tornado Dynamics. Vol. 2, Thunderstorms: A Social and Technological Documentary, 2nd ed. E. Kessler, Ed., University of Oklahoma Press, 197–236.

  • Davies-Jones, R. P., and H. E. Brooks, 1993: Mesocyclogenesis from a theoretical perspective. The Tornado: Its Structure, Dynamics, Prediction, and Hazards, Geophys. Monogr., Vol. 79, Amer. Geophys. Union, 105–114.

  • Davies-Jones, R. P., R. J. Trapp, and H. B. Bluestein, 2001: Tornadoes and tornadic storms. Severe Convective Storms, Meteor. Monogr., No. 28, Amer. Meteor. Soc., 167–222.

  • Dowell, D. C., and H. B. Bluestein, 1997: The Arcadia, Oklahoma, storm of 17 May 1981: Analysis of a supercell during tornadogenesis. Mon. Wea. Rev., 125, 2562–2582.

    • Search Google Scholar
    • Export Citation

  • Dowell, D. C., and H. B. Bluestein, 2002a: The 8 June 1995 McLean, Texas, storm. Part I: Observations of cyclic tornadogenesis. Mon. Wea. Rev., 130, 2626–2648.

    • Search Google Scholar
    • Export Citation

  • Dowell, D. C., and H. B. Bluestein, 2002b: The 8 June 1995 McLean, Texas, storm. Part II: Cyclic tornado formation, maintenance, and dissipation. Mon. Wea. Rev., 130, 2649–2670.

    • Search Google Scholar
    • Export Citation

  • Dowell, D. C., C. R. Alexander, J. M. Wurman, and L. J. Wicker, 2005: Centrifuging of hydrometeors and debris in tornadoes: Radar-reflectivity patterns and wind measurement errors. Mon. Wea. Rev., 133, 1501–1524.

    • Search Google Scholar
    • Export Citation

  • Frame, J., P. Markowski, Y. Richardson, J. Straka, and J. Wurman, 2009: Polarimetric and dual Doppler radar observations of the Lipscomb County, Texas, supercell thunderstorm on 23 May 2002. Mon. Wea. Rev., 137, 544–561.

    • Search Google Scholar
    • Export Citation

  • French, M. M., H. B. Bluestein, D. C. Dowell, L. J. Wicker, M. R. Kramar, and A. L. Pazmany, 2008: High-resolution, mobile Doppler radar observations of cyclic mesocyclogenesis in a supercell. Mon. Wea. Rev., 136, 4997–5016.

    • Search Google Scholar
    • Export Citation

  • Fujita, T. T., 1981: Tornadoes and downbursts in the context of generalized planetary scales. J. Atmos. Sci., 38, 1511–1534.

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

  • 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

  • Kosiba, K., and J. Wurman, 2010: The three-dimensional axisymmetric wind field structure of the Spencer, South Dakota, 1998 tornado. J. Atmos. Sci., 67, 3074–3083.

    • Search Google Scholar
    • Export Citation

  • Lee, W.-C., and J. Wurman, 2005: The diagnosed structure of the Mulhall tornado. J. Atmos. Sci., 62, 2373–2393.

  • Majcen, M., P. Markowski, Y. Richardson, D. Dowell, and J. Wurman, 2008: Multipass objective analysis of Doppler radar data. J. Atmos. Oceanic Technol., 25, 1845–1858.

    • Search Google Scholar
    • Export Citation

  • Markowski, P., E. Rasmussen, J. Straka, R. Davies-Jones, Y. Richardson, and R. J. Trapp, 2008: Vortex lines within low-level mesocyclones obtained from pseudo Doppler radar observations. Mon. Wea. Rev., 136, 3513–3535.

    • Search Google Scholar
    • Export Citation

  • Markowski, P., M. Majcen, Y. Richardson, J. Marquis, and J. Wurman, 2011a: Characteristics of the wind field in a trio of nontornadic low-level mesocyclones observed by the Doppler on Wheels radars. Electron. J. Severe Storms Meteor., 6 (3), 1–48.

    • Search Google Scholar
    • Export Citation

  • Markowski, P., and Coauthors, 2011b: Observations from VORTEX 2: The pretornadic phase of the Goshen County, Wyoming, supercell. Preprints, 35th Int. Conf. on Radar Meteorology, Pittsburgh, PA, Amer. Meteor. Soc., 8B.1. [Available online at http://ams.confex.com/ams/35Radar/webprogram/Manuscript/Paper191881/radar35.pdf.]

  • Marquis, J., Y. Richardson, J. Wurman, and P. Markowski, 2008: Single- and dual-Doppler analysis of a tornadic vortex and surrounding storm-scale flow in the Crowell, Texas, supercell of 30 April 2000. Mon. Wea. Rev., 136, 5017–5043.

    • Search Google Scholar
    • Export Citation

  • 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, 1145–1163.

    • Search Google Scholar
    • Export Citation

  • Rasmussen, E. N., and J. M. Straka, 2007: Evolution of low-level angular momentum in the 2 June 1995 Dimmitt, Texas, tornado cyclone. J. Atmos. Sci., 64, 1365–1378.

    • Search Google Scholar
    • Export Citation

  • Rasmussen, E. N., J. M. Straka, R. P. Davies-Jones, C. A. Doswell, F. H. Carr, M. D. Eilts, and D. R. MacGorman, 1994: Verification of the Origins of Rotation in Tornadoes Experiment: VORTEX. Bull. Amer. Meteor. Soc., 75, 995–1006.

    • Search Google Scholar
    • Export Citation

  • Rasmussen, E. N., R. Davies-Jones, and R. L. Holle, 2003: Terrestrial photogrammetry of weather images acquired in uncontrolled circumstances. J. Atmos. Oceanic Technol., 20, 1790–1803.

    • 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, 271–292.

    • Search Google Scholar
    • Export Citation

  • Ryzhkov, A. V., T. J. Schuur, D. W. Burgess, and D. S. Zrnic, 2005: Polarimetric tornado detection. J. Appl. Meteor., 44, 557–570.

    • Search Google Scholar
    • Export Citation

  • Stout, G. E., and F. A. Huff, 1953: Radar records Illinois tornadogenesis. Bull. Amer. Meteor. Soc., 34, 281–284.

  • Tanamachi, R. L., H. B. Bluestein, W.-C. Lee, M. Bell, and A. Pazmany, 2007: Ground based velocity track display (GBVTD) analysis of W-band Doppler radar data in a tornado near Stockton, Kansas, on 15 May 1999. Mon. Wea. Rev., 135, 783–800.

    • Search Google Scholar
    • Export Citation

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

    • Search Google Scholar
    • Export Citation

  • Trapp, J. R., 1999: Observations of nontornadic low-level mesocyclones and attendant tornadogenesis failure during VORTEX. Mon. Wea. Rev., 127, 1693–1705.

    • Search Google Scholar
    • Export Citation

  • Wakimoto, R. M., and B. E. Martner, 1992: Observations of a Colorado tornado. Part II: Combined photogrammetric and Doppler radar analysis. Mon. Wea. Rev., 120, 522–543.

    • Search Google Scholar
    • Export Citation

  • Wakimoto, R. M., and C. Liu, 1998: The Garden City, Kansas, storm during VORTEX 95. Part II: The wall cloud and tornado. Mon. Wea. Rev., 126, 393–408.

    • Search Google Scholar
    • Export Citation

  • Wakimoto, R. M., and H. Cai, 2000: Analysis of a nontornadic storm during VORTEX 95. Mon. Wea. Rev., 128, 565–592.

  • Wakimoto, R. M., W.-C. Lee, H. B. Bluestein, C.-H. Liu, and P. H. Hildebrand, 1996: ELDORA observations during VORTEX 95. Bull. Amer. Meteor. Soc., 77, 1465–1481.

    • Search Google Scholar
    • Export Citation

  • Wakimoto, R. M., C. Liu, and H. Cai, 1998: The Garden City, Kansas, storm during VORTEX 95. Part I: Overview of the storm’s life cycle and mesocyclogenesis. Mon. Wea. Rev., 126, 372–392.

    • Search Google Scholar
    • Export Citation

  • Wakimoto, R. M., H. V. Murphey, D. C. Dowell, and H. B. Bluestein, 2003: The Kellerville tornado during VORTEX: Damage survey and Doppler radar analyses. Mon. Wea. Rev., 131, 2197–2221.

    • Search Google Scholar
    • Export Citation

  • Wakimoto, R. M., N. T. Atkins, and J. Wurman, 2011: The LaGrange tornado during VORTEX2. Part I: Photogrammetric analysis of the tornado combined with single-Doppler radar data. Mon. Wea. Rev., 139, 2233–2258.

    • Search Google Scholar
    • Export Citation

  • Wood, V. T., R. A. Brown, and D. C. Dowell, 2009: Simulated WSR-88D velocity and reflectivity signatures of numerically modeled tornadoes. J. Atmos. Oceanic Technol., 26, 876–893.

    • Search Google Scholar
    • Export Citation

  • Wurman, J., and S. Gill, 2000: Finescale radar observations of the Dimmitt, Texas (2 June 1995), tornado. Mon. Wea. Rev., 128, 2135–2164.

    • Search Google Scholar
    • Export Citation

  • Wurman, J., and C. Alexander, 2005: The 30 May 1998 Spencer, South Dakota, storm. Part II: Comparison of observed damage and radar-derived winds in the tornadoes. Mon. Wea. Rev., 133, 97–119.

    • Search Google Scholar
    • Export Citation

  • Wurman, J., J. Straka, and E. Rasmussen, 1996: Fine scale Doppler radar observation of tornadoes. Science, 272, 1774–1777.

  • Wurman, J., J. Straka, E. Rasmussen, M. Randall, and A. Zahrai, 1997: Design and deployment of a portable, pencil-beam, pulsed, 3-cm Doppler radar. J. Atmos. Oceanic Technol., 14, 1502–1512.

    • Search Google Scholar
    • Export Citation

  • Wurman, J., C. Alexander, P. Robinson, and Y. Richardson, 2007a: Low-level winds in tornadoes and potential catastrophic tornado impacts in urban areas. Bull. Amer. Meteor. Soc., 88, 31–46.

    • Search Google Scholar
    • Export Citation

  • Wurman, J., Y. Richardson, C. Alexander, S. Weygandt, and P.-F. Zhang, 2007b: Dual-Doppler and single-Doppler analysis of a tornadic storm undergoing mergers and repeated tornadogenesis. Mon. Wea. Rev., 135, 736–758.

    • Search Google Scholar
    • Export Citation

  • Wurman, J., Y. Richardson, C. Alexander, S. Weygandt, and P.-F. Zhang, 2007c: Dual-Doppler analysis of winds and vorticity budget terms near a tornado. Mon. Wea. Rev., 135, 2392–2405.

    • Search Google Scholar
    • Export Citation

  • Wurman, J., P. Robinson, C. Alexander, and K. A. Kosiba, 2008: Rapid-scan mobile radar 3D GBVTD and traditional analysis of tornadogenesis. Preprints, 24th Conf. on Severe Local Storms, Savannah, GA, Amer. Meteor. Soc., P13.6. [Available online at http://ams.confex.com/ams/24SLS/techprogram/paper_142176.htm.]

  • Wurman, J., H. Bluestein, D. Burgess, D. Dowell, P. Markowski, Y. Richardson, and L. Wicker, 2010: VORTEX2: The Verification of the Origins of Rotation in Tornadoes Experiment. Proc. Sixth European Conf. on Radar Meteorology and Hydrology, Sibiu, Romania, European Meteorological Society, 10 pp. [Available online at http://www.erad2010.org/pdf/oral/wednesday/mesoscale/02_ERAD2010_0160.pdf.]

  • Zehnder, J. A., J. Hu, and A. Razdan, 2007: A stereo photogrammetric technique applied to orographic convection. Mon. Wea. Rev., 135, 2265–2277.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 363 108 5
PDF Downloads 242 85 6