• Altinger de Schwarzkopf, M. L., and L. C. Russo, 1982: Severe storms and tornadoes in Argentina. Preprints, 12th Conf. on Severe Local Storms, San Antonio, TX, Amer. Meteor. Soc., 5962.

  • Banacos, P. C., and D. M. Schultz, 2005: The use of moisture flux convergence in forecasting convective initiation: Historical and operational perspectives. Wea. Forecasting, 20, 351366, doi:10.1175/WAF858.1.

    • Search Google Scholar
    • Export Citation
  • Buzzi, A., and S. Tibaldi, 1978: Cyclogenesis in the lee of the Alps: A case study. Quart. J. Roy. Meteor. Soc., 104, 271287, doi:10.1002/qj.49710444004.

    • Search Google Scholar
    • Export Citation
  • Campetella, C. M., and C. S. Vera, 2002: The influence of the Andes Mountains on the South American low-level flow. Geophys. Res. Lett., 29, 1826, doi:10.1029/2002GL015451.

    • Search Google Scholar
    • Export Citation
  • Carlson, T. N., S. G. Benjamin, G. S. Forbes, and Y.-F. Li, 1983: Elevated mixed layers in the regional severe storm environment: Conceptual model and case studies. Mon. Wea. Rev., 111, 14531474, doi:10.1175/1520-0493(1983)111<1453:EMLITR>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Cecil, D. J., 2009: Passive microwave brightness temperatures as proxies for hailstorms. J. Appl. Meteor. Climatol., 48, 12811286, doi:10.1175/2009JAMC2125.1.

    • Search Google Scholar
    • Export Citation
  • Cecil, D. J., 2011: Relating passive 37-GHz scattering to radar profiles in strong convection. J. Appl. Meteor. Climatol., 50, 233240, doi:10.1175/2010JAMC2506.1.

    • Search Google Scholar
    • Export Citation
  • Cecil, D. J., and C. B. Blankenship, 2012: Toward a global climatology of severe hailstorms as estimated by satellite passive microwave imagers. J. Climate, 25, 687703, doi:10.1175/JCLI-D-11-00130.1.

    • Search Google Scholar
    • Export Citation
  • Chaboureau, J.-P., F. Guichard, J.-L. Redelsperger, and J.-P. Lafore, 2004: The role of stability and moisture in the diurnal cycle of convection over land. Quart. J. Roy. Meteor. Soc., 130, 31053117, doi:10.1256/qj.03.132.

    • Search Google Scholar
    • Export Citation
  • Chen, F., and J. Dudhia, 2001: Coupling an advanced land-surface/hydrology model with the Penn State/NCAR MM5 modeling system. Part I: Model description and implementation. Mon. Wea. Rev., 129, 569585, doi:10.1175/1520-0493(2001)129<0569:CAALSH>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Chung, Y. S., 1977: On the orographic influence and lee cyclogenesis in the Andes, the Rockies, and the east Asian mountains. Arch. Meteor. Geophys. Bioklimatol., 26, 112, doi:10.1007/BF02246530.

    • Search Google Scholar
    • Export Citation
  • Davis, C. A., 1997: The modification of baroclinic waves by the Rocky Mountains. J. Atmos. Sci., 54, 848868, doi:10.1175/1520-0469(1997)054<0848:TMOBWB>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Douglas, M. W., M. Nicolini, and C. A. Saulo, 1998: Observational evidences of a low level jet east of the Andes during January-March 1998. Meteorologica, 23, 6372.

    • Search Google Scholar
    • Export Citation
  • Dudhia, J., 1989: Numerical study of convection observed during the winter monsoon experiment using a mesoscale two-dimensional model. J. Atmos. Sci., 46, 30773107, doi:10.1175/1520-0469(1989)046<3077:NSOCOD>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Durkee, J. D., T. L. Mote, and J. M. Shepherd, 2009: The contribution of mesoscale convective complexes into rainfall across subtropical South America. J. Climate, 22, 45904605, doi:10.1175/2009JCLI2858.1.

    • Search Google Scholar
    • Export Citation
  • Emanuel, K. A., M. Fantini, and A. J. Thorpe, 1987: Baroclinic instability in an environment of small stability to slantwise moist convection. Part I: Two-dimensional models. J. Atmos. Sci., 44, 15591573, doi:10.1175/1520-0469(1987)044<1559:BIIAEO>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Gan, M. A., and V. B. Rao, 1994: The influence of the Andes Cordillera on transient disturbances. Mon. Wea. Rev., 122, 11411157, doi:10.1175/1520-0493(1994)122<1141:TIOTAC>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Gutzler, D. S., and T. M. Wood, 1990: Structure of large-scale convective anomalies over tropical oceans. J. Climate, 3, 483496, doi:10.1175/1520-0442(1990)003<0483:SOLSCA>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Hong, S.-Y., Y. Noh, and J. Dudhia, 2006: A new vertical diffusion package with an explicit treatment of entrainment processes. Mon. Wea. Rev., 134, 23182341, doi:10.1175/MWR3199.1.

    • Search Google Scholar
    • Export Citation
  • Houze, R. A., Jr., 2004: Mesoscale convective systems. Rev. Geophys., 42, RG4003, doi:10.1029/2004RG000150.

  • Houze, R. A., Jr., 2014: Cloud Dynamics. 2nd ed. Academic Press/Elsevier, 432 pp.

  • Houze, R. A., Jr., B. F. Smull, and P. Dodge, 1990: Mesoscale organization of springtime rainstorms in Oklahoma. Mon. Wea. Rev., 118, 613654, doi:10.1175/1520-0493(1990)118<0613:MOOSRI>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Houze, R. A., Jr., D. C. Wilton, and B. F. Smull, 2007: Monsoon convection in the Himalayan region as seen by the TRMM Precipitation Radar. Quart. J. Roy. Meteor. Soc., 133, 13891411, doi:10.1002/qj.106.

    • Search Google Scholar
    • Export Citation
  • Houze, R. A., Jr., K. L. Rasmussen, S. Medina, S. R. Brodzik, and U. Romatschke, 2011: Anomalous atmospheric events leading to the summer 2010 floods in Pakistan. Bull. Amer. Meteor. Soc., 92, 291298, doi:10.1175/2010BAMS3173.1.

    • Search Google Scholar
    • Export Citation
  • Houze, R. A., Jr., K. L. Rasmussen, M. D. Zuluaga, and S. R. Brodzik, 2015: The variable nature of convection in the tropics and subtropics: A legacy of 16 years of the Tropical Rainfall Measuring Mission satellite. Rev. Geophys., 53, 9941021, doi:10.1002/2015RG000488.

    • Search Google Scholar
    • Export Citation
  • Iguchi, T., T. Kozu, R. Meneghini, J. Awaka, and K. Okamoton, 2000: Rain-profiling algorithm for the TRMM precipitation radar. J. Appl. Meteor., 39, 20382052, doi:10.1175/1520-0450(2001)040<2038:RPAFTT>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Iguchi, T., T. Kozu, J. Kwiatkowski, R. Meneghini, J. Awaka, and K. Okamoto, 2009: Uncertainties in the rain profiling algorithm for the TRMM precipitation radar. J. Meteor. Soc. Japan, 87A, 130, doi:10.2151/jmsj.87A.1.

    • Search Google Scholar
    • Export Citation
  • Insel, N., C. J. Poulsen, and T. A. Ehlers, 2010: Influence of the Andes Mountains on South American moisture transport, convection, and precipitation. Climate Dyn., 35, 14771492, doi:10.1007/s00382-009-0637-1.

    • Search Google Scholar
    • Export Citation
  • Kain, J. S., and J. M. Fritsch, 1993: Convective parameterization for mesoscale models: The Kain-Fritsch scheme. The Representation of Cumulus Convection in Numerical Models, Meteor. Monogr., No. 46, Amer. Meteor. Soc., 165–170.

  • Kalnay, E., and Coauthors, 1996: The NCEP/NCAR 40-Year Reanalysis Project. Bull. Amer. Meteor. Soc., 77, 437471, doi:10.1175/1520-0477(1996)077<0437:TNYRP>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Kasahara, A., 1966: The dynamical influence of orography on the large-scale motion of the atmosphere. J. Atmos. Sci., 23, 259271, doi:10.1175/1520-0469(1966)023<0259:TDIOOO>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Marengo, J., W. Soares, C. Saulo, and M. Nicolini, 2004: Climatology of the LLJ east of the Andes as derived from the NCEP reanalyses. J. Climate, 17, 22612280, doi:10.1175/1520-0442(2004)017<2261:COTLJE>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Matsudo, C. M., and P. V. Salio, 2011: Severe weather reports and proximity to deep convection over Northern Argentina. Atmos. Res., 100, 523537, doi:10.1016/j.atmosres.2010.11.004.

    • Search Google Scholar
    • Export Citation
  • McGinley, J. A., 1982: A diagnosis of Alpine lee cyclogenesis. Mon. Wea. Rev., 110, 12711287, doi:10.1175/1520-0493(1982)110<1271:ADOALC>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Medina, S., R. A. Houze Jr., A. Kumar, and D. Niyogi, 2010: Summer monsoon convection in the Himalayan region: Terrain and land cover effects. Quart. J. Roy. Meteor. Soc., 136, 593616, doi:10.1002/qj.601.

    • Search Google Scholar
    • Export Citation
  • Mlawer, E. J., S. J. Taubnam, P. D. Brown, M. J. Iacono, and S. A. Clough, 1997: Radiative transfer for inhomogeneous atmospheres: RRTM, a validated correlated-k model for the longwave. J. Geophys. Res., 102, 16 66316 682, doi:10.1029/97JD00237.

    • Search Google Scholar
    • Export Citation
  • Nascimento, E. L., and I. P. V. O. Marcelino, 2005: Preliminary analysis of the 3 January 2005 tornadoes in Criciuma/SC. Bull. Braz. Meteor. Soc., 29, 3344.

    • Search Google Scholar
    • Export Citation
  • Nogués-Paegle, J., and K. C. Mo, 1997: Alternating wet and dry conditions over South America during summer. Mon. Wea. Rev., 125, 279291, doi:10.1175/1520-0493(1997)125<0279:AWADCO>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Palmén, E., and C. W. Newton, 1969: Atmospheric Circulation Systems. Academic Press, 603 pp.

  • Rasmussen, K. L., 2014: On the nature of severe orographic thunderstorms near the Andes in subtropical South America. Ph.D. dissertation, University of Washington, 227 pp.

  • Rasmussen, K. L., and R. A. Houze Jr., 2011: Orogenic convection in subtropical South America as seen by the TRMM satellite. Mon. Wea. Rev., 139, 23992420, doi:10.1175/MWR-D-10-05006.1.

    • Search Google Scholar
    • Export Citation
  • Rasmussen, K. L., S. L. Choi, M. D. Zuluaga, and R. A. Houze Jr., 2013: TRMM precipitation bias in extreme storms in South America. Geophys. Res. Lett., 40, 34573461, doi:10.1002/grl.50651.

    • Search Google Scholar
    • Export Citation
  • Rasmussen, K. L., M. D. Zuluaga, and R. A. Houze Jr., 2014: Severe convection and lightning in subtropical South America. Geophys. Res. Lett., 41, 73597366, doi:10.1002/2014GL061767.

    • Search Google Scholar
    • Export Citation
  • Rasmussen, K. L., A. J. Hill, V. E. Toma, M. D. Zuluaga, P. J. Webster, and R. A. Houze Jr., 2015: Multiscale analysis of three consecutive years of anomalous flooding in Pakistan. Quart. J. Roy. Meteor. Soc., 141, 12591276, doi:10.1002/qj.2433.

    • Search Google Scholar
    • Export Citation
  • Rasmussen, K. L., M. M. Chaplin, M. D. Zuluaga, and R. A. Houze Jr., 2016: Contribution of extreme convective storms to rainfall in South America. J. Hydrometeor., 17, 353367, doi:10.1175/JHM-D-15-0067.1.

    • Search Google Scholar
    • Export Citation
  • Romatschke, U., and R. A. Houze, 2010: Extreme summer convection in South America. J. Climate, 23, 37613791, doi:10.1175/2010JCLI3465.1.

    • Search Google Scholar
    • Export Citation
  • Rozante, J. R., and I. F. A. Cavalcanti, 2008: Regional Eta model experiments: SALLJEX and MCS development. J. Geophys. Res., 113, D17106, doi:10.1029/2007JD009566.

    • Search Google Scholar
    • Export Citation
  • Salio, P., M. Nicolini, and E. J. Zipser, 2007: Mesoscale convective systems over southeastern South America and their relationship with the South American low-level jet. Mon. Wea. Rev., 135, 12901309, doi:10.1175/MWR3305.1.

    • Search Google Scholar
    • Export Citation
  • Satyamurty, P., C. C. Ferreira, and M. A. Gan, 1990: Cyclonic vortices over South America. Tellus, 42A, 194201, doi:10.1034/j.1600-0870.1990.00016.x.

    • Search Google Scholar
    • Export Citation
  • Saulo, A. C., M. Nicolini, and S. C. Chou, 2000: Model characterization of the South American low-level flow during the 1997–1998 spring-summer season. Climate Dyn., 16, 867881, doi:10.1007/s003820000085.

    • Search Google Scholar
    • Export Citation
  • Schultz, D. M., and C. A. Doswell III, 2000: Analyzing and forecasting Rocky Mountain lee cyclogenesis often associated with strong winds. Wea. Forecasting, 15, 152173, doi:10.1175/1520-0434(2000)015<0152:AAFRML>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Skamarock, W. C., and Coauthors, 2008: A description of the Advanced Research WRF version 3. NCAR Tech. Note NCAR/TN-475+STR, 113 pp., doi:10.5065/D68S4MVH.

  • Smith, R. B., 1984: A theory of lee cyclogenesis. J. Atmos. Sci., 41, 11591168, doi:10.1175/1520-0469(1984)041<1159:ATOLC>2.0.CO;2.

  • Smith, R. B., 1986: Further development of a theory of lee cyclogenesis. J. Atmos. Sci., 43, 15821602, doi:10.1175/1520-0469(1986)043<1582:FDOATO>2.0.CO;2.

    • Search Google Scholar
    • Export Citation
  • Thompson, G., P. R. Field, R. M. Rasmussen, and W. D. Hall, 2008: Explicit forecasts of winter precipitation using an improved bulk microphysics scheme. Part II: Implementation of a new snow parameterization. Mon. Wea. Rev., 136, 50955115, doi:10.1175/2008MWR2387.1.

    • Search Google Scholar
    • Export Citation
  • Velasco, I., and J. M. Fritsch, 1987: Mesoscale convective complexes in the Americas. J. Geophys. Res., 92, 95919613, doi:10.1029/JD092iD08p09591.

    • Search Google Scholar
    • Export Citation
  • Vera, C., and Coauthors, 2006: The South American Low-Level Jet Experiment. Bull. Amer. Meteor. Soc., 87, 6377, doi:10.1175/BAMS-87-1-63.

    • Search Google Scholar
    • Export Citation
  • Yuan, J., and R. A. Houze Jr., 2010: Global variability of mesoscale convective system anvil structure from A-train satellite data. J. Climate, 23, 58645888, doi:10.1175/2010JCLI3671.1.

    • Search Google Scholar
    • Export Citation
  • Zhang, G. J., 2003: Roles of tropospheric and boundary layer forcing in the diurnal cycle of convection in the U.S. southern great plains. Geophys. Res. Lett., 30, 2281, doi:10.1029/2003GL018554.

    • Search Google Scholar
    • Export Citation
  • Zipser, E. J., D. J. Cecil, C. Liu, S. W. Nesbitt, and D. P. Yorty, 2006: Where are the most intense thunderstorms on Earth? Bull. Amer. Meteor. Soc., 87, 10571071, doi:10.1175/BAMS-87-8-1057.

    • Search Google Scholar
    • Export Citation
  • Zuluaga, M. D., and R. A. Houze Jr., 2013: Evolution of the population of precipitating convective systems over the equatorial Indian Ocean in active phases of the Madden–Julian oscillation. J. Atmos. Sci., 70, 27132725, doi:10.1175/JAS-D-12-0311.1.

    • Search Google Scholar
    • Export Citation
  • Zuluaga, M. D., and R. A. Houze Jr., 2015: Extreme convection of the near-equatorial Americas, Africa, and adjoining oceans as seen by TRMM. Mon. Wea. Rev., 143, 298316, doi:10.1175/MWR-D-14-00109.1.

    • Search Google Scholar
    • Export Citation
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Convective Initiation near the Andes in Subtropical South America

K. L. RasmussenMesoscale and Microscale Meteorology Laboratory, National Center for Atmospheric Research, Boulder, Colorado

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R. A. Houze Jr.Department of Atmospheric Sciences, University of Washington, Seattle, Washington

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Abstract

Satellite radar and radiometer data indicate that subtropical South America has some of the deepest and most extreme convective storms on Earth. This study uses the full 15-yr TRMM Precipitation Radar dataset in conjunction with high-resolution simulations from the Weather Research and Forecasting Model to better understand the physical factors that control the climatology of high-impact weather in subtropical South America. The occurrence of intense storms with an extreme horizontal dimension is generally associated with lee cyclogenesis and a strengthening South American low-level jet (SALLJ) in the La Plata basin. The orography of the Andes is critical, and model sensitivity calculations removing and/or reducing various topographic features indicate the orographic control on the initiation of convection and its upscale growth into mesoscale convective systems (MCSs). Reduced Andes experiments show more widespread convective initiation, weaker average storm intensity, and more rapid propagation of the MCS to the east (reminiscent of the MCS life cycle downstream of lower mountains such as the Rockies). With reduced Andes, lee cyclogenesis and SALLJ winds are weaker, while they are stronger in increased Andes runs. The presence of the Sierras de Córdoba (secondary mountain range east of the Andes in Argentina) focuses convective initiation and results in more intense storms in experiments with higher Andes. Average CAPE and CIN values for each terrain modification simulation show that reduced Andes runs had lower CIN and CAPE, while increased Andes runs had both stronger CAPE and CIN. From this research, a conceptual model for convective storm environments leading to convective initiation has been developed for subtropical South America.

Corresponding author address: Kristen Lani Rasmussen, National Center for Atmospheric Research, 3450 Mitchell Lane, Boulder, CO 80301. E-mail: kristenr@ucar.edu

Abstract

Satellite radar and radiometer data indicate that subtropical South America has some of the deepest and most extreme convective storms on Earth. This study uses the full 15-yr TRMM Precipitation Radar dataset in conjunction with high-resolution simulations from the Weather Research and Forecasting Model to better understand the physical factors that control the climatology of high-impact weather in subtropical South America. The occurrence of intense storms with an extreme horizontal dimension is generally associated with lee cyclogenesis and a strengthening South American low-level jet (SALLJ) in the La Plata basin. The orography of the Andes is critical, and model sensitivity calculations removing and/or reducing various topographic features indicate the orographic control on the initiation of convection and its upscale growth into mesoscale convective systems (MCSs). Reduced Andes experiments show more widespread convective initiation, weaker average storm intensity, and more rapid propagation of the MCS to the east (reminiscent of the MCS life cycle downstream of lower mountains such as the Rockies). With reduced Andes, lee cyclogenesis and SALLJ winds are weaker, while they are stronger in increased Andes runs. The presence of the Sierras de Córdoba (secondary mountain range east of the Andes in Argentina) focuses convective initiation and results in more intense storms in experiments with higher Andes. Average CAPE and CIN values for each terrain modification simulation show that reduced Andes runs had lower CIN and CAPE, while increased Andes runs had both stronger CAPE and CIN. From this research, a conceptual model for convective storm environments leading to convective initiation has been developed for subtropical South America.

Corresponding author address: Kristen Lani Rasmussen, National Center for Atmospheric Research, 3450 Mitchell Lane, Boulder, CO 80301. E-mail: kristenr@ucar.edu
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