Editorial Type:
Article
Article Type:
Research Article

Simulation of a Serial Upstream-Propagating Mesoscale Convective System Event over Southeastern South America Using Composite Initial Conditions

Vagner Anabor Laboratório de Física da Atmosfera, Departamento de Física, Universidade Federal de Santa Maria, Santa Maria, Brazil

Search for other papers by Vagner Anabor in
Current site
Google Scholar
PubMed Close
,
David J. Stensrud NOAA/National Severe Storms Laboratory, Norman, Oklahoma

Search for other papers by David J. Stensrud in
Current site
Google Scholar
PubMed Close
, and
Osvaldo L. L. de Moraes Laboratório de Física da Atmosfera, Departamento de Física, Universidade Federal de Santa Maria, Santa Maria, Brazil

Search for other papers by Osvaldo L. L. de Moraes in
Current site
Google Scholar
PubMed Close
Print Publication:
01 Jul 2009
DOI:
https://doi.org/10.1175/2008MWR2617.1
Page(s):
2144–2163
Restricted access

Abstract

Serial upstream-propagating mesoscale convective system (MCS) events over southeastern South America are important contributors to the local hydrologic cycle as they can provide roughly half of the total monthly summer precipitation. However, the mechanisms of upstream propagation for these events have not been explored. To remedy this situation, a numerical simulation of the composite environmental conditions from 10 observed serial MCS events is conducted. Results indicate that the 3-day simulation from the composite yields a reasonable evolution of the large-scale environment and produces a large region of organized convection in the warm sector over an extended period as seen in observations. Upstream propagation of the convective region is produced and is tied initially to the development and evolution of untrapped internal gravity waves. However, as convective downdrafts develop and begin to merge and form a surface cold pool in the simulation, the cold pool and its interaction with the environmental low-level flow also begins to play a role in convective evolution. While the internal gravity waves and cold pool interact over a several hour period to control the convective development, the cold pool eventually dominates and determines the propagation of the convective region by the end of the simulation. This upstream propagation of a South American convective region resembles the southward burst convective events described over the United States and highlights the complex interactions and feedbacks that challenge accurate forecasts of convective system evolution.

Corresponding author address: Vagner Anabor, Laboratório de Física da Atmosfera, Departamento de Física, Universidade Federal de Santa Maria, 97119.900 Santa Maria, RS, Brazil. Email: anabor@mail.ufsm.br

Abstract

Serial upstream-propagating mesoscale convective system (MCS) events over southeastern South America are important contributors to the local hydrologic cycle as they can provide roughly half of the total monthly summer precipitation. However, the mechanisms of upstream propagation for these events have not been explored. To remedy this situation, a numerical simulation of the composite environmental conditions from 10 observed serial MCS events is conducted. Results indicate that the 3-day simulation from the composite yields a reasonable evolution of the large-scale environment and produces a large region of organized convection in the warm sector over an extended period as seen in observations. Upstream propagation of the convective region is produced and is tied initially to the development and evolution of untrapped internal gravity waves. However, as convective downdrafts develop and begin to merge and form a surface cold pool in the simulation, the cold pool and its interaction with the environmental low-level flow also begins to play a role in convective evolution. While the internal gravity waves and cold pool interact over a several hour period to control the convective development, the cold pool eventually dominates and determines the propagation of the convective region by the end of the simulation. This upstream propagation of a South American convective region resembles the southward burst convective events described over the United States and highlights the complex interactions and feedbacks that challenge accurate forecasts of convective system evolution.

Corresponding author address: Vagner Anabor, Laboratório de Física da Atmosfera, Departamento de Física, Universidade Federal de Santa Maria, 97119.900 Santa Maria, RS, Brazil. Email: anabor@mail.ufsm.br

Save
Cover Monthly Weather Review
Monthly Weather Review

  • Anabor, V., 2004: Descriptive analyses of meso-α convective systems by GOES-8 satellite images. M.S. thesis, Departament of Remote Sensing, Universidade Federal do Rio Grande do Sul, Brazil, 78 pp.

  • Anabor, V., D. J. Stensrud, and O. L. L. de Moraes, 2008: Serial upstream-propagating mesoscale convective system events over southeastern South America. Mon. Wea. Rev., 136 , 3087–3105.

    • Search Google Scholar
    • Export Citation

  • Berbery, E. H., and V. R. Barros, 2002: The hydrologic cycle of the La Plata Basin in South America. J. Hydrometeor., 3 , 630–645.

    • Search Google Scholar
    • Export Citation

  • Byerle, L., and J. Paegle, 2002: Description of the seasonal cycle of low-level flows flanking the Andes and their interannual variability. Meteorologica, 27 , 71–88.

    • 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

  • 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

  • Dudhia, J., 1989: Numerical study of convection observed during the winter monsoon experiment using a mesoscale two-dimensional model. J. Atmos. Sci., 46 , 3077–3107.

    • Search Google Scholar
    • Export Citation

  • Dudhia, J., 1996: A multi-layer soil temperature model for MM5. Preprints, Sixth PSU/NCAR Mesoscale Model Users’ Workshop, Boulder, CO, PSU–NCAR, 49–50. [Available from NCAR, P.O. Box 3000, Boulder, CO 80307-3000].

    • Search Google Scholar
    • Export Citation

  • Eom, J. K., 1975: Analysis of the internal gravity wave occurrence of 19 April 1970 in the Midwest. Mon. Wea. Rev., 103 , 217–226.

    • Search Google Scholar
    • Export Citation

  • Garreaud, R. D., and J. M. Wallace, 1998: Summertime incursions of midlatitude air into subtropical and tropical South America. Mon. Wea. Rev., 126 , 2713–2733.

    • Search Google Scholar
    • Export Citation

  • Gossard, E. E., and H. W. Hooke, 1975: Waves in the Atmosphere. Elsevier, 472 pp.

  • James, I. N., and D. L. T. Anderson, 1984: The seasonal mean flow and distribution of large-scale weather systems in the Southern Hemisphere: The effects of moisture transports. Quart. J. Roy. Meteor. Soc., 110 , 943–966.

    • Search Google Scholar
    • Export Citation

  • Jirak, I. L., W. R. Cotton, and R. L. McAnelly, 2003: Satellite and radar survey of mesoscale convective system development. Mon. Wea. Rev., 131 , 2428–2449.

    • 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.

    • Search Google Scholar
    • Export Citation

  • Laing, A. G., and J. M. Fritsch, 1997: The global population of mesoscale convective complexes. Quart. J. Roy. Meteor. Soc., 123 , 389–405.

    • Search Google Scholar
    • Export Citation

  • Laing, A. G., and J. M. Fritsch, 2000: The large-scale environments of the global populations of mesoscale convective complexes. Mon. Wea. Rev., 128 , 2756–2776.

    • Search Google Scholar
    • Export Citation

  • Lichtenstein, E. R., 1980: La depresion del noroeste Argentino (The northwestern Argentina low). Ph.D. dissertation, University of Buenos Aires, Buenos Aires, Argentina, 223 pp.

  • Lin, Y-L., R. D. Farley, and H. D. Orville, 1983: Bulk parameterization of the snow field in a cloud model. J. Climate Appl. Meteor., 22 , 1065–1092.

    • Search Google Scholar
    • Export Citation

  • Lindzen, R. S., and K. K. Tung, 1976: Banded convective activity and ducted gravity axes. Mon. Wea. Rev., 104 , 1602–1617.

  • Maddox, R. A., 1980: Mesoscale convective complexes. Bull. Amer. Meteor. Soc., 61 , 1374–1387.

  • Maddox, R. A., 1983: Large-scale meteorological conditions associated with midlatitude, mesoscale convective complexes. Mon. Wea. Rev., 111 , 126–140.

    • Search Google Scholar
    • Export Citation

  • Maddox, R. A., R. D. Perkey, and J. Fritsch, 1981: Evolution of upper tropospheric features during the development of a mesoscale convective complex. J. Atmos. Sci., 38 , 1664–1674.

    • Search Google Scholar
    • Export Citation

  • Marengo, J. A., W. R. Soares, C. Saulo, and M. Nicolini, 2004: Climatology of the low-level jet east of the Andes as a derived from the NCEP–NCAR reanalyses: Characteristics and temporal variability. J. Climate, 17 , 2261–2280.

    • Search Google Scholar
    • Export Citation

  • Mlawer, E. J., S. J. Taubman, P. D. Brown, M. J. Iacono, and S. A. Clough, 1997: Radiative transfer for inhomogeneous atmosphere: RRTM, a validated correlated-k model for the longwave. J. Geophys. Res., 102 , (D14). 16663–16682.

    • Search Google Scholar
    • Export Citation

  • Nesbitt, S. W., R. Cifelli, and S. A. Rutledge, 2006: Storm morphology and rainfall characteristics of TRMM precipitation features. Mon. Wea. Rev., 134 , 2702–2721.

    • Search Google Scholar
    • Export Citation

  • Nicolini, M., and A. C. Saulo, 2000: ETA characterization of the 1997–98 warm season Chaco jet cases. Preprints, Sixth Int. Conf. on Southern Hemisphere Meteorology and Oceanography, Santiago, Chile, Amer. Meteor. Soc., 330–331.

    • Search Google Scholar
    • Export Citation

  • Nicolini, M., A. C. Saulo, J. C. Torres, and P. Salio, 2002: Enhanced precipitation over Southeastern South America related to strong low-level jet events during austral warm season. Meteorológica, 27 , 89–98.

    • Search Google Scholar
    • Export Citation

  • Noh, Y., W. G. Cheon, S-Y. Hong, and S. Raasch, 2003: Improvement of the K-profile model for the planetary boundary layer based on large eddy simulation data. Bound.-Layer Meteor., 107 , 401–427.

    • Search Google Scholar
    • Export Citation

  • Paegle, J., 2000: American low level jets in observations and theory: The ALLS project. Preprints, Sixth Int. Conf. on Southern Hemisphere Meteorology and Oceanography, Santiago, Chile, Amer. Meteor. Soc., 161–162.

    • Search Google Scholar
    • Export Citation

  • Porter, J. M., L. L. Means, J. E. Hovde, and W. B. Chappell, 1955: A synoptic study on the formation of squall lines in the north central United States. Bull. Amer. Meteor. Soc., 36 , 390–396.

    • Search Google Scholar
    • Export Citation

  • Rasmusson, E. M., and K. Mo, 1996: Large-scale atmospheric moisture cycling as evaluated from NMC global analysis and forecast products. J. Climate, 9 , 3276–3297.

    • 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 , 1290–1309.

    • Search Google Scholar
    • Export Citation

  • Saulo, A. C., M. E. Seluchi, and M. Nicolini, 2004: A case study of a chaco low-level jet event. Mon. Wea. Rev., 132 , 2669–2683.

  • Saulo, A. C., J. Ruiz, and Y. G. Skabar, 2007: Synergism between the low-level jet and organized convection at its exit region. Mon. Wea. Rev., 135 , 1310–1326.

    • Search Google Scholar
    • Export Citation

  • Seluchi, M. E., A. C. Saulo, M. Nicolini, and P. Satyamurty, 2003: The northwestern Argentinean low: A study of two typical events. Mon. Wea. Rev., 131 , 2361–2378.

    • Search Google Scholar
    • Export Citation

  • Silva Dias, M. A. F., and Coauthors, 2002: A case study of convective organization into precipitating lines in the Southwest Amazon during the WETAMC and TRMM-LBA. J. Geophys. Res., 107 , 8078. doi:10.1029/2001JD000375.

    • Search Google Scholar
    • Export Citation

  • Silva Dias, P. L., D. Moreira, and M. F. Silva Dias, 2001: Downscaling resolution and the moisture budget of the Plata Basin. Proc. IX Congreso Latinoamericano e Iberico de Meteorología y VIII Congreso Argentino de Meteorología, La Meteorología y el Medio Ambiente en el Siglo XXI, Buenos Aires, Argentina, Centro Argentino de Meteorológos, 8.C.27-341.

    • Search Google Scholar
    • Export Citation

  • Skamarock, W. C., J. B. Klemp, J. Dudhia, D. O. Gill, D. M. Barker, W. Wang, and J. G. Powers, 2005: A description of the Advanced Research WRF version 2. NCAR Tech. Note TN-468STR, 88 pp. [Available from NCAR, P.O. Box 3000, Boulder, CO 80307.].

    • Search Google Scholar
    • Export Citation

  • Stensrud, D. J., 1996a: Importance of low-level jets to climate: A review. J. Climate, 9 , 1698–1711.

  • Stensrud, D. J., 1996b: Effects of a persistent, midlatitude mesoscale region of convection on the large-scale environment during the warm season. J. Atmos. Sci., 53 , 3503–3527.

    • Search Google Scholar
    • Export Citation

  • Stensrud, D. J., and J. M. Fritsch, 1993: Mesoscale convective systems in weakly forced large-scale environments. Part I: Observations. Mon. Wea. Rev., 121 , 3326–3344.

    • Search Google Scholar
    • Export Citation

  • Stensrud, D. J., and J. M. Fritsch, 1994: Mesoscale convective systems in weakly forced large-scale environments. Part III: Numerical simulations and implications for operational forecasting. Mon. Wea. Rev., 122 , 2084–2104.

    • Search Google Scholar
    • Export Citation

  • Velasco, I. Y., and J. M. Fritsch, 1987: Mesoscale convective complexes in the Americas. J. Geophys. Res., 92 , 9591–9613.

  • Vera, C. S., and Coauthors, 2006: The South American low-level jet experiment. Bull. Amer. Meteor. Soc., 87 , 63–77.

  • Wolf, B. J., and D. R. Johnson, 1995: The mesoscale forcing of a midlatitude upper-tropospheric jet streak by a simulated convective system. Part I: Mass circulation and ageostrophic processes. Mon. Wea. Rev., 123 , 1059–1087.

    • 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 , 1057–1071.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 1659 1424 67
PDF Downloads 159 28 3