Mesoscale Convective Vortex that Causes Tornado-Like Vortices over the Sea: A Potential Risk to Maritime Traffic

Eigo Tochimoto Atmosphere and Ocean Research Institute, The University of Tokyo, Tokyo, Japan

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Sho Yokota Meteorological Research Institute, Japan Meteorological Agency, Tsukuba, Japan

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Hiroshi Niino Atmosphere and Ocean Research Institute, The University of Tokyo, Tokyo, Japan

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Wataru Yanase Meteorological Research Institute, Japan Meteorological Agency, Tsukuba, Japan

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Abstract

Strong gusty winds in a weak maritime extratropical cyclone (EC) over the Tsushima Strait in the southwestern Sea of Japan capsized several fishing boats on 1 September 2015. A C-band Doppler radar recorded a spiral-shaped reflectivity pattern associated with a convective system and a Doppler velocity pattern of a vortex with a diameter of 30 km [meso-β-scale vortex (MBV)] near the location of the wreck. A high-resolution numerical simulation with horizontal grid interval of 50 m successfully reproduced the spiral-shaped precipitation pattern associated with the MBV and tornado-like strong vortices that had a maximum wind speed exceeding 50 m s−1 and repeatedly developed in the MBV. The simulated MBV had a strong cyclonic circulation comparable to a mesocyclone in a supercell storm. Unlike mesocyclones associated with a supercell storm, however, its vorticity was largest near the surface and decreased monotonically with increasing height. The strong vorticity of the MBV near the surface originated from a horizontal shear line in the EC. The tornado-like vortices developed in a region of strong horizontal shear in the western part of the MBV, suggesting that they were caused by a shear instability.

© 2019 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).

Corresponding author: Eigo Tochimoto, tochimoto@aori.u-tokyo.ac.jp

Abstract

Strong gusty winds in a weak maritime extratropical cyclone (EC) over the Tsushima Strait in the southwestern Sea of Japan capsized several fishing boats on 1 September 2015. A C-band Doppler radar recorded a spiral-shaped reflectivity pattern associated with a convective system and a Doppler velocity pattern of a vortex with a diameter of 30 km [meso-β-scale vortex (MBV)] near the location of the wreck. A high-resolution numerical simulation with horizontal grid interval of 50 m successfully reproduced the spiral-shaped precipitation pattern associated with the MBV and tornado-like strong vortices that had a maximum wind speed exceeding 50 m s−1 and repeatedly developed in the MBV. The simulated MBV had a strong cyclonic circulation comparable to a mesocyclone in a supercell storm. Unlike mesocyclones associated with a supercell storm, however, its vorticity was largest near the surface and decreased monotonically with increasing height. The strong vorticity of the MBV near the surface originated from a horizontal shear line in the EC. The tornado-like vortices developed in a region of strong horizontal shear in the western part of the MBV, suggesting that they were caused by a shear instability.

© 2019 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).

Corresponding author: Eigo Tochimoto, tochimoto@aori.u-tokyo.ac.jp
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  • American Meteorological Society, 2015: “Line-end vortices.” Glossary of Meteorology, http://glossary.ametsoc.org/wiki/Line-end_vortices.

  • Atkins, N. T., and M. St. Laurent, 2009: Bow echo mesovortices. Part II: Their genesis. Mon. Wea. Rev., 137, 15141532, https://doi.org/10.1175/2008MWR2650.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Atkins, N. T., J. M. Arnott, R. W. Przybylinski, R. A. Wolf, and B. D. Ketcham, 2004: Vortex structure and evolution within bow echoes. Part I: Single-Doppler and damage analysis of the 29 June 1998 derecho. Mon. Wea. Rev., 132, 22242242, https://doi.org/10.1175/1520-0493(2004)132<2224:VSAEWB>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Atkins, N. T., C. S. Bouchard, R. W. Przybylinski, R. J. Trapp, and G. Schmocker, 2005: Damaging surface wind mechanisms within the 10 June 2003 Saint Louis bow echo during BAMEX. Mon. Wea. Rev., 133, 22752296, https://doi.org/10.1175/MWR2973.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Browning, K. A., 1964: Airflow and precipitation trajectories within severe local storms which travel to the right of the winds. J. Atmos. Sci., 21, 634639, https://doi.org/10.1175/1520-0469(1964)021<0634:AAPTWS>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Conzemius, R. J., R. W. Moore, M. T. Montgomery, and C. A. Davis, 2007: Mesoscale convective vortex formation in a weakly sheared moist neutral environment. J. Atmos. Sci., 64, 14431466, https://doi.org/10.1175/JAS3898.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Corfidi, S., S. Weiss, J. Kain, S. Corfidi, R. Rabin, and J. Levit, 2010: Revisiting the 3–4 April 1974 Super Outbreak of tornadoes. Wea. Forecasting, 25, 465510, https://doi.org/10.1175/2009WAF2222297.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Craven, J. P., and H. E. Brooks, 2004: Baseline climatology of sounding derived parameters associated with deep, moist convection. Natl. Wea. Dig., 28, 1324.

    • Search Google Scholar
    • Export Citation
  • Dahl, J. M. L., M. D. Parker, and L. J. Wicker, 2012: Uncertainties in trajectory calculations within near-surface mesocyclones of simulated supercells. Mon. Wea. Rev., 140, 29592966, https://doi.org/10.1175/MWR-D-12-00131.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Davis, C. A., and S. B. Trier, 2007: Mesoscale convective vortices observed during BAMEX. Part I: Kinematic and thermodynamic structure. Mon. Wea. Rev., 135, 20292049, https://doi.org/10.1175/MWR3398.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Davis, C. A., and T. J. Galarneau, 2009: The vertical structure of mesoscale convective vortices. J. Atmos. Sci., 66, 686704, https://doi.org/10.1175/2008JAS2819.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Davis, C. A., and Coauthors, 2004: The bow echo and MCV experiment: Observations and opportunities. Bull. Amer. Meteor. Soc., 85, 10751093, https://doi.org/10.1175/BAMS-85-8-1075.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Deardorff, J. W., 1980: Stratocumulus-capped mixed layers derived from a three-dimensional model. Bound.-Layer Meteor., 18, 495527, https://doi.org/10.1007/BF00119502.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Fritsch, J. M., J. D. Murphy, and J. S. Kain, 1994: Warm core vortex amplification over land. J. Atmos. Sci., 51, 17801807, https://doi.org/10.1175/1520-0469(1994)051<1780:WCVAOL>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Fujita, T. T., 1978: Manual of downburst identification for project Nimrod. Satellite and Mesometeorology Research Paper 156, Dept. of Geophysical Science, University of Chicago, 104 pp. [NTIS-PB-286048]

  • Fujita, T. T., 1979: Objective, operation, and results of Project NIMROD. Preprints, 11th Conf. on Severe Local Storms, Kansas City, MO, Amer. Meteor. Soc., 259–266.

  • Funk, T., K. Darmofal, J. Kirkpatrick, V. DeWald, R. Przbylinski, G. Schmocker, and Y.-J. Lin, 1999: Storm reflectivity and mesocyclone evolution associated with the 15 April 1994 squall line of Kentucky and southern Indiana. Wea. Forecasting, 14, 976993, https://doi.org/10.1175/1520-0434(1999)014<0976:SRAMEA>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Ikawa, M., H. Mizuno, T. Matsuo, M. Murakami, Y. Yamada, and K. Saito, 1991: Numerical modeling of the convective snow cloud over the Sea of Japan: Precipitation mechanism and sensitivity to ice crystal nucleation rates. J. Meteor. Soc. Japan, 69, 641667, https://doi.org/10.2151/jmsj1965.69.6_641.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Johns, R. H., and C. A. Doswell, 1992: Severe local storms forecasting. Wea. Forecasting, 7, 588612, https://doi.org/10.1175/1520-0434(1992)007<0588:SLSF>2.0.CO;2.

    • Crossref
    • 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, 359377, https://doi.org/10.1175/1520-0469(1983)040<0359:ASOTTR>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Lemon, L. R., and C. A. Doswell III, 1979: Severe thunderstorm evolution and mesocyclone structure as related to tornadogenesis. Mon. Wea. Rev., 107, 11841197, https://doi.org/10.1175/1520-0493(1979)107<1184:STEAMS>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Maddox, R. A., 1980: Mesoscale convective complexes. Bull. Amer. Meteor. Soc., 61, 13741400, https://doi.org/10.1175/1520-0477(1980)061<1374:MCC>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Markowski, P., and Y. Richardson, 2014: The influence of environmental low-level shear and cold pools on tornadogenesis: Insights from idealized simulations. J. Atmos. Sci., 71, 243275, https://doi.org/10.1175/JAS-D-13-0159.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Mashiko, W., 2016a: A numerical study of the 6 May 2012 Tsukuba City Supercell Tornado. Part I: Vorticity sources of low-level and midlevel mesocyclones. Mon. Wea. Rev., 144, 10691092, https://doi.org/10.1175/MWR-D-15-0123.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Mashiko, W., 2016b: A numerical study of the 6 May 2012 Tsukuba City Supercell Tornado. Part II: Mechanisms of tornadogenesis. Mon. Wea. Rev., 144, 30773098, https://doi.org/10.1175/MWR-D-15-0122.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Mashiko, W., H. Niino, and T. Kato, 2009: Numerical simulation of tornadogenesis in an outer-rainband minisupercell of Typhoon Shanshan on 17 September 2006. Mon. Wea. Rev., 137, 42384260, https://doi.org/10.1175/2009MWR2959.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • McCaul, E. W., Jr., 1991: Buoyancy and shear characteristics of hurricane–tornado environments. Mon. Wea. Rev., 119, 19541978, https://doi.org/10.1175/1520-0493(1991)119<1954:BASCOH>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Menard, R. D., and J. M. Fritsch, 1989: A mesoscale convective complex-generated inertially stable warm core vortex. Mon. Wea. Rev., 117, 12371261, https://doi.org/10.1175/1520-0493(1989)117<1237:AMCCGI>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Miller, R., 1972: Notes on analysis and severe-storm forecasting procedures of the Air Force Global Weather Center. Air Weather Service Tech. Rep. 200, rev. ed. Air Weather Service, Scott Air Force Base, IL, 184 pp.

  • Murakami, M., 1990: Numerical modeling of dynamical and microphysical evolution of an isolated convective cloud—The 19 July 1981 CCOPE cloud. J. Meteor. Soc. Japan, 68, 107128, https://doi.org/10.2151/jmsj1965.68.2_107.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Nakanishi, M., and H. Niino, 2006: An improved Mellor-Yamada Level-3 model: Its numerical stability and application to a regional prediction of advection fog. Bound.-Layer Meteor., 119, 397407, https://doi.org/10.1007/s10546-005-9030-8.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Newton, C. W., 1967: Severe convective storms. Advances in Geophysics, Vol. 12, Academic Press, 257–303.

    • Crossref
    • Export Citation
  • Noda, A., and H. Niino, 2010: A numerical investigation of a supercell tornado: Genesis and vorticity budget. J. Meteor. Soc. Japan, 88, 135159, https://doi.org/10.2151/jmsj.2010-203.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Novlan, D. J., and W. M. Gray, 1974: Hurricane-spawned tornadoes. Mon. Wea. Rev., 102, 476488, https://doi.org/10.1175/1520-0493(1974)102<0476:HST>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Orlanski, I., 1975: A rational subdivision of scales for atmospheric processes. Bull. Amer. Meteor. Soc., 56, 527530, https://doi.org/10.1175/1520-0477-56.5.527.

    • Search Google Scholar
    • Export Citation
  • Przybylinski, R. W., 1995: The bow echo: Observations, numerical simulations, and severe weather detection methods. Wea. Forecasting, 10, 203218, https://doi.org/10.1175/1520-0434(1995)010<0203:TBEONS>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Rayleigh, L., 1894: The Theory of Sound. Vol. II. 2nd ed. Macmillan, 522 pp.

  • Roebber, P. J., D. M. Schultz, and R. Romero, 2002: Synoptic regulation of the 3 May 1999 tornado outbreak. Wea. Forecasting, 17, 399429, https://doi.org/10.1175/1520-0434(2002)017<0399:SROTMT>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Saito, K., and Coauthors, 2006: The operational JMA nonhydrostatic mesoscale model. Mon. Wea. Rev., 134, 12661298, https://doi.org/10.1175/MWR3120.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Schenkman, A., and M. Xue, 2016: Bow-echo mesovortices: A review. Atmos. Res., 170, 1–13, https://doi.org/10.1016/j.atmosres.2015.11.003.

    • Crossref
    • Export Citation
  • Schenkman, A., M. Xue, and A. Shapiro, 2012: Tornadogenesis in a simulated mesovortex within a mesoscale convective system. J. Atmos. Sci., 69, 33723390, https://doi.org/10.1175/JAS-D-12-038.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Sueki, K., and H. Niino, 2016: Toward better assessment of tornado potential in typhoons: Significance of considering entrainment effects for CAPE. Geophys. Res. Lett., 43, 12 59712 604, https://doi.org/10.1002/2016GL070349.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Tamura, Y., and Coauthors, 2016: Development and implementation of Japanese Enhanced Fujita scale. 28th Conf. on Severe Local Storms, Portland, OR, Amer. Meteor. Soc., 6B.5, https://ams.confex.com/ams/28SLS/webprogram/Paper300864.html.

  • Tochimoto, E., and H. Niino, 2016: Structural and environmental characteristics of extratropical cyclones that cause tornado outbreaks in the warm sector. Mon. Wea. Rev., 144, 945969, https://doi.org/10.1175/MWR-D-15-0015.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Tochimoto, E., and H. Niino, 2017: Structural and environmental characteristics of extratropical cyclones associated with tornado outbreaks in the warm sector: An idealized numerical study. Mon. Wea. Rev., 145, 117136, https://doi.org/10.1175/MWR-D-16-0107.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Tochimoto, E., and H. Niino, 2018: Structure and environment of tornado-spawning extratropical cyclones around Japan. J. Meteor. Soc. Japan, 96, 355380, https://doi.org/10.2151/jmsj.2018-043.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Trier, S. B., and C. A. Davis, 2002: Influence of balanced motions on heavy precipitation within a long-lived convectively generated vortex. Mon. Wea. Rev., 130, 877899, https://doi.org/10.1175/1520-0493(2002)130<0877:IOBMOH>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wakimoto, R. M., and J. W. Wilson, 1989: Non-supercell tornadoes. Mon. Wea. Rev., 117, 11131140, https://doi.org/10.1175/1520-0493(1989)117<1113:NST>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wakimoto, R. M., H. V. Murphey, C. A. Davis, and N. T. Atkins, 2006a: High winds generated by bow echoes. Part II: The relationship between the mesovortices and damaging straight-line winds. Mon. Wea. Rev., 134, 28132829, https://doi.org/10.1175/MWR3216.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wakimoto, R. M., H. V. Murphey, A. Nester, D. P. Jorgensen, and N. T. Atkins, 2006b: High winds generated by bow echoes. Part I: Overview of the Omaha bow echo 5 July 2003 storm during BAMEX. Mon. Wea. Rev., 134, 27932812, https://doi.org/10.1175/MWR3215.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Weisman, M., and C. A. Davis, 1998: Mechanisms for the generation of mesoscale vortices within quasi-linear convective systems. J. Atmos. Sci., 55, 26032622, https://doi.org/10.1175/1520-0469(1998)055<2603:MFTGOM>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Weisman, M., C. Evans, and L. Bosart, 2013: The 8 May 2009 superderecho: Analysis of a real-time explicit convective forecast. Wea. Forecasting, 28, 863892, https://doi.org/10.1175/WAF-D-12-00023.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wicker, L. J., and R. Wilhelmson, 1995: Simulation and analysis of tornado development and decay within a threedimensional supercell thunderstorm. J. Atmos. Sci., 52, 26752703, https://doi.org/10.1175/1520-0469(1995)052<2675:SAAOTD>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Xu, X., M. Xue, and Y. Wang, 2015: The genesis of mesovortices within a real-data simulation of a bow echo system. J. Atmos. Sci., 72, 19631986, https://doi.org/10.1175/JAS-D-14-0209.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Yokota, S., H. Niino, H. Seko, M. Kunii, and H. Yamauchi, 2018: Important factors for tornadogenesis as revealed by high-resolution ensemble forecasts of the Tsukuba supercell tornado of 6 May 2012 in Japan. Mon. Wea. Rev., 146, 11091132, https://doi.org/10.1175/MWR-D-17-0254.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Zhang, D.-L., 1992: The formation of a cooling-induced mesovortex in the trailing stratiform region of a midlatitude squall line. Mon. Wea. Rev., 120, 27632785, https://doi.org/10.1175/1520-0493(1992)120<2763:TFOACI>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
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