• Adams, D. K., and A. C. Comrie, 1997: The North American monsoon. Bull. Amer. Meteor. Soc., 78, 21972213, https://doi.org/10.1175/1520-0477(1997)078<2197:TNAM>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Adler, R. F., G. J. Huffman, and P. R. Keehn, 1994: Global tropical rain estimates from microwave‐adjusted geosynchronous IR data. Remote Sens. Rev., 11, 125152, https://doi.org/10.1080/02757259409532262.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Ahmed, F., C. Schumacher, Z. Feng, and S. Hagos, 2016: A retrieval of tropical latent heating using the 3D structure of precipitation features. J. Appl. Meteor. Climatol., 55, 19651982, https://doi.org/10.1175/JAMC-D-15-0038.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Amador, J. A., 1998: A climatic feature of the tropical Americas: The trade wind easterly jet. Top. Meteor. Oceanogr., 5, 113.

  • Amador, J. A., 2008: The Intra-Americas Sea low-level jet overview and future research. Trends and Directions in Climate Research, L. Gimeno, R. Garcia Herrera, and R. M. Trigo, Eds., Blackwell, 153188.

    • Search Google Scholar
    • Export Citation
  • Amador, J. A., E. J. Alfaro, O. G. Lizano, and V. O. Magaña, 2006: Atmospheric forcing of the eastern tropical Pacific: A review. Prog. Oceanogr., 69, 101142, https://doi.org/10.1016/j.pocean.2006.03.007.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Amante, C., and B. W. Eakins, 2009: ETOPO1 1 arc-minute global relief model: Procedures, data sources and analysis. NOAA Tech. Memo. NESDIS NGDC-24, 25 pp., https://www.ngdc.noaa.gov/mgg/global/relief/ETOPO1/docs/ETOPO1.pdf.

    • Search Google Scholar
    • Export Citation
  • Arritt, R. W., J. M. Wilczak, and G. S. Young, 1992: Observations and numerical modeling of an elevated mixed layer. Mon. Wea. Rev., 120, 28692880, https://doi.org/10.1175/1520-0493(1992)120<2869:OANMOA>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Belanger, J. I., M. T. Jelinek, and J. A. Curry, 2016: A climatology of easterly waves in the tropical Western Hemisphere. Geosci. Data J., 3, 4049, https://doi.org/10.1002/gdj3.40.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Brammer, A., and C. D. Thorncroft, 2015: Variability and evolution of African easterly wave structures and their relationship with tropical cyclogenesis over the eastern Atlantic. Mon. Wea. Rev., 143, 49754995, https://doi.org/10.1175/MWR-D-15-0106.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Burpee, R. W., 1972: The origin and structure of easterly waves in the lower troposphere of North Africa. J. Atmos. Sci., 29, 7790, https://doi.org/10.1175/1520-0469(1972)029<0077:TOASOE>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Charney, J., and M. Stern, 1962: On the stability of internal baroclinic jets in a rotating atmosphere. J. Atmos. Sci., 19, 159172, https://doi.org/10.1175/1520-0469(1962)019<0159:OTSOIB>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Cook, K. H., and E. K. Vizy, 2010: Hydrodynamics of the Caribbean low-level jet and its relationship to precipitation. J. Climate, 23, 14771494, https://doi.org/10.1175/2009JCLI3210.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Curtis, S., and D. W. Gamble, 2008: Regional variations of the Caribbean mid-summer drought. Theor. Appl. Climatol., 94, 2534, https://doi.org/10.1007/s00704-007-0342-0.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Davis, C., C. Snyder, and A. C. Didlake Jr., 2008: A vortex-based perspective of eastern Pacific tropical cyclone formation. Mon. Wea. Rev., 136, 24612477, https://doi.org/10.1175/2007MWR2317.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Dee, D. P., and Coauthors, 2011: The ERA-Interim reanalysis: Configuration and performance of the data assimilation system. Quart. J. Roy. Meteor. Soc., 137, 553597, https://doi.org/10.1002/qj.828.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • de Szoeke, S. P., Y. Wang, S.-P. Xie, and T. Miyama, 2006: Effect of shallow cumulus convection on the eastern Pacific climate in a coupled model. Geophys. Res. Lett., 33, L17713, https://doi.org/10.1029/2006GL026715.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • De Wekker, S. F. J., and M. Kossmann, 2015: Convective boundary layer heights over mountainous terrain—A review of concepts. Front. Earth Sci., 3, 77, https://doi.org/10.3389/feart.2015.00077.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Dickinson, M., and J. Molinari, 2000: Climatology of sign reversals of the meridional potential vorticity gradient over Africa and Australia. Mon. Wea. Rev., 128, 38903900, https://doi.org/10.1175/1520-0493(2001)129<3890:COSROT>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Drazin, P. G., and W. H. Reid, 2004: Hydrodynamic Stability. Cambridge University Press, 605 pp.

  • Farfán, L. M., and J. A. Zehnder, 1997: Orographic influence on the synoptic-scale circulations associated with the genesis of Hurricane Guillermo (1991). Mon. Wea. Rev., 125, 26832698, https://doi.org/10.1175/1520-0493(1997)125<2683:OIOTSS>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Ferreira, R. N., and W. H. Schubert, 1997: Barotropic aspects of ITCZ breakdown. J. Atmos. Sci., 54, 261285, https://doi.org/10.1175/1520-0469(1997)054<0261:BAOIB>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Fjørtoft, R., 1950: Application of integral theorems in deriving criteria of stability for laminar flows and for the baroclinic circular vortex. Geofys. Publ., 17, 152.

    • Search Google Scholar
    • Export Citation
  • Fuchs-Stone, Ž., D. J. Raymond, and S. Sentić, 2020: OTREC2019: Convection over the east Pacific and southwest Caribbean. Geophys. Res. Lett., 47, e2020GL087564, https://doi.org/10.1029/2020GL087564.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Gamble, D. W., and S. Curtis, 2008: Caribbean precipitation: Review, model and prospect. Prog. Phys. Geogr., 32, 265276, https://doi.org/10.1177/0309133308096027.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Gelaro, R., R. H. Langland, S. Pellerin, and R. Todling, 2010: The THORPEX observation impact intercomparison experiment. Mon. Wea. Rev., 138, 40094025, https://doi.org/10.1175/2010MWR3393.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Gordon, A. L., 1967: Circulation of the Caribbean Sea. J. Geophys. Res., 72, 62076223, https://doi.org/10.1029/JZ072i024p06207.

  • Hagos, S., and Coauthors, 2010: Estimates of tropical diabatic heating profiles: Commonalities and uncertainties. J. Climate, 23, 542558, https://doi.org/10.1175/2009JCLI3025.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hastenrath, S., 1978: On modes of tropical circulation and climate anomalies. J. Atmos. Sci., 35, 22222231, https://doi.org/10.1175/1520-0469(1978)035<2222:OMOTCA>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hastenrath, S., 1984: Interannual variability and annual cycle: Mechanisms of circulation and climate in the tropical Atlantic sector. Mon. Wea. Rev., 112, 10971107, https://doi.org/10.1175/1520-0493(1984)112<1097:IVAACM>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Herrera, E., V. Magaña, and E. Caetano, 2015: Air–sea interactions and dynamical processes associated with the midsummer drought. Int. J. Climatol., 35, 15691578, https://doi.org/10.1002/joc.4077.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Higgins, R. W., Y. Chen, and A. V. Douglas, 1999: Interannual variability of the North American warm season precipitation regime. J. Climate, 12, 653680, https://doi.org/10.1175/1520-0442(1999)012<0653:IVOTNA>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Hoskins, B. J., M. McIntyre, and A. W. Robertson, 1985: On the use and significance of isentropic potential vorticity maps. Quart. J. Roy. Meteor. Soc., 111, 877946, https://doi.org/10.1002/qj.49711147002.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Huaman, L., and C. Schumacher, 2018: Assessing the vertical latent heating structure of the east Pacific ITCZ using the CloudSat CPR and TRMM PR. J. Climate, 31, 25632577, https://doi.org/10.1175/JCLI-D-17-0590.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Huffman, G. J., and Coauthors, 2007: The TRMM Multisatellite Precipitation Analysis (TMPA): Quasi-global, multiyear, combined-sensor precipitation estimates at fine scales. J. Hydrometeor., 8, 3855, https://doi.org/10.1175/JHM560.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Janiga, M. A., and C. D. Thorncroft, 2013: Regional differences in the kinematic and thermodynamic structure of African easterly waves. Quart. J. Roy. Meteor. Soc., 139, 15981614, https://doi.org/10.1002/qj.2047.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kao, H.-Y., and J.-Y. Yu, 2009: Contrasting eastern-Pacific and central-Pacific types of ENSO. J. Climate, 22, 615632, https://doi.org/10.1175/2008JCLI2309.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kerns, B., K. Greene, and E. Zipser, 2008: Four years of tropical ERA-40 vorticity maxima tracks. Part I: Climatology and vertical vorticity structure. Mon. Wea. Rev., 136, 43014319, https://doi.org/10.1175/2008MWR2390.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kiladis, G. N., C. D. Thorncroft, and N. M. J. Hall, 2006: Three-dimensional structure and dynamics of African easterly waves. Part I: Observations. J. Atmos. Sci., 63, 22122230, https://doi.org/10.1175/JAS3741.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Krishnamurti, T. N., B. Jha, H. S. Bedi, and U. C. Mohanty, 2000: Diabatic effects on potential vorticity over the global tropics. J. Meteor. Soc. Japan, 78, 527542, https://doi.org/10.2151/jmsj1965.78.5_527.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Kucieńska, B., G. B. Raga, and V. M. Torres-Puente, 2012: Climatology of precipitation and lightning over the Pacific coast of southern Mexico retrieved from Tropical Rainfall Measuring Mission satellite products and World Wide Lightning Location Network data. Int. J. Remote Sens., 33, 28312850, https://doi.org/10.1080/01431161.2011.621905.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Lee, H.-T., 2014: Climate Algorithm Theoretical Basis Document (C-ATBD): Outgoing longwave radiation (OLR)—Daily. NOAA CDR Program Algorithm Theoretical Basis Doc., 46 pp.

    • Search Google Scholar
    • Export Citation
  • Liebmann, B., and C. A. Smith, 1996: Description of a complete (interpolated) outgoing longwave radiation dataset. Bull. Amer. Meteor. Soc., 77, 12751277, https://doi.org/10.1175/1520-0477-77.6.1274.

    • Search Google Scholar
    • Export Citation
  • Ling, J., and C. Zhang, 2011: Structural evolution in heating profiles of the MJO in global reanalyses and TRMM retrievals. J. Climate, 24, 825842, https://doi.org/10.1175/2010JCLI3826.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Magaña, V., J. A. Amador, and S. Medina, 1999: The midsummer drought over Mexico and Central America. J. Climate, 12, 15771588, https://doi.org/10.1175/1520-0442(1999)012<1577:TMDOMA>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Maloney, E. D., and D. L. Hartmann, 2001: The Madden–Julian oscillation, barotropic dynamics, and North Pacific tropical cyclone formation. Part I: Observations. J. Atmos. Sci., 58, 25452558, https://doi.org/10.1175/1520-0469(2001)058<2545:TMJOBD>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Maloney, E. D., and J. T. Kiehl, 2002: Intraseasonal eastern Pacific precipitation and SST variations in a GCM coupled to a slab ocean model. J. Climate, 15, 29893007, https://doi.org/10.1175/1520-0442(2002)015<2989:IEPPAS>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Mapes, B. E., T. T. Warner, and M. Xu, 2003: Diurnal patterns of rainfall in northwestern South America. Part III: Diurnal gravity waves and nocturnal convection offshore. Mon. Wea. Rev., 131, 830844, https://doi.org/10.1175/1520-0493(2003)131<0830:DPORIN>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Mapes, B. E., P. Liu, and N. Buenning, 2005: Indian monsoon onset and the Americas midsummer drought: Out-of-equilibrium responses to smooth seasonal forcing. J. Climate, 18, 11091115, https://doi.org/10.1175/JCLI-3310.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Molinari, J., D. Knight, M. Dickinson, D. Vollaro, and S. Skubis, 1997: Potential vorticity, easterly waves, and eastern Pacific tropical cyclogenesis. Mon. Wea. Rev., 125, 26992708, https://doi.org/10.1175/1520-0493(1997)125<2699:PVEWAE>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Nichols, J. T., and R. C. Murphy, 1944: A collection of fishes from the Panama Bight, Pacific Ocean. Bull. Amer. Mus. Nat. Hist., 83, 4.

    • Search Google Scholar
    • Export Citation
  • Palmen, E., 1948: On the formation and structure of tropical hurricanes. Geophysica, 3, 2638, https://www.geophysica.fi/pdf/geophysica_1948_3_1_026_palmen.pdf.

    • Search Google Scholar
    • Export Citation
  • Petersen, W. A., R. Cifelli, D. J. Boccippio, S. A. Rutledge, and C. Fairall, 2003: Convection and easterly wave structures observed in the eastern Pacific warm pool during EPIC-2001. J. Atmos. Sci., 60, 17541773, https://doi.org/10.1175/1520-0469(2003)060<1754:CAEWSO>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Philander, S. G. H., 1983: El Niño Southern Oscillation phenomena. Nature, 302, 295301, https://doi.org/10.1038/302295a0.

  • Rasmussen, R. M., P. Smolarkiewicz, and J. Warner, 1989: On the dynamics of Hawaiian cloud bands: Comparison of model results with observations and island climatology. J. Atmos. Sci., 46, 15891608, https://doi.org/10.1175/1520-0469(1989)046<1589:OTDOHC>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Raymond, D. J., C. Lopez-Carrillo, and L. L. Cavazos, 1998: Case-studies of developing east Pacific easterly waves. Quart. J. Roy. Meteor. Soc., 124, 20052034, https://doi.org/10.1002/qj.49712455011.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Raymond, D. J., and Coauthors, 2004: EPIC2001 and the coupled ocean–atmosphere system of the tropical east Pacific. Bull. Amer. Meteor. Soc., 85, 13411354, https://doi.org/10.1175/BAMS-85-9-1341.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Reed, R. J., D. C. Norquist, and E. E. Recker, 1977: The structure and properties of African wave disturbances as observed during phase III of GATE. Mon. Wea. Rev., 105, 317333, https://doi.org/10.1175/1520-0493(1977)105<0317:TSAPOA>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Reynolds, R. W., N. A. Rayner, T. M. Smith, D. C. Stokes, and W. Wang, 2002: An improved in situ and satellite SST analysis for climate. J. Climate, 15, 16091625, https://doi.org/10.1175/1520-0442(2002)015<1609:AIISAS>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Romero-Centeno, R., J. Zavala-Hidalgo, and G. B. Raga, 2007: Midsummer gap winds and low-level circulation over the eastern tropical Pacific. J. Climate, 20, 37683784, https://doi.org/10.1175/JCLI4220.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Russell, J. O. H., and A. Aiyyer, 2020: The potential vorticity structure and dynamics of African easterly waves. J. Atmos. Sci., 77, 871890, https://doi.org/10.1175/JAS-D-19-0019.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Rydbeck, A. V., and E. D. Maloney, 2014: Energetics of east Pacific easterly waves during intraseasonal events. J. Climate, 27, 76037621, https://doi.org/10.1175/JCLI-D-14-00211.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Rydbeck, A. V., and E. D. Maloney, 2015: On the convective coupling and moisture organization of east Pacific easterly waves. J. Atmos. Sci., 72, 38503870, https://doi.org/10.1175/JAS-D-15-0056.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Rydbeck, A. V., E. D. Maloney, and G. J. Alaska Jr., 2017: In situ initiation of east Pacific easterly waves in a regional model. J. Atmos. Sci., 74, 333351, https://doi.org/10.1175/JAS-D-16-0124.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Schumacher, C., R. A. Houze Jr., and I. Kraucunas, 2004: The tropical dynamical response to latent heating estimates derived from the TRMM Precipitation Radar. J. Atmos. Sci., 61, 13411358, https://doi.org/10.1175/1520-0469(2004)061<1341:TTDRTL>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Serra, Y. L., and R. A. Houze Jr., 2002: Observations of variability on synoptic timescales in the east Pacific ITCZ. J. Atmos. Sci., 59, 17231743, https://doi.org/10.1175/1520-0469(2002)059<1723:OOVOST>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Serra, Y. L., and K. Geil, 2017: Historical and projected eastern Pacific and Intra-Americas Sea TD-wave activity in a selection of IPCC AR5 models. J. Climate, 30, 22692294, https://doi.org/10.1175/JCLI-D-16-0453.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Serra, Y. L., G. N. Kiladis, and M. F. Cronin, 2008: Horizontal and vertical structure of easterly waves in the Pacific ITCZ. J. Atmos. Sci., 65, 12661284, https://doi.org/10.1175/2007JAS2341.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Serra, Y. L., G. N. Kiladis, and K. I. Hodges, 2010: Tracking and mean structure of easterly waves over the Intra-Americas Sea. J. Climate, 23, 48234840, https://doi.org/10.1175/2010JCLI3223.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Serra, Y. L., X. Jiang, B. Tian, J. Amador-Astua, E. D. Maloney, and G. N. Kiladis, 2014: Tropical intraseasonal modes of the atmosphere. Annu. Rev. Environ. Resour., 39, 189215, https://doi.org/10.1146/annurev-environ-020413-134219.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Smith, R. B., P. Schafer, D. J. Kirshbaum, and E. Regina, 2009: Orographic precipitation in the tropics: Experiments in Dominica. J. Atmos. Sci., 66, 16981716, https://doi.org/10.1175/2008JAS2920.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Steenburgh, W. J., D. M. Schultz, and B. A. Colle, 1998: The structure and evolution of gap outflow over the Gulf of Tehuantepec, Mexico. Mon. Wea. Rev., 126, 26732691, https://doi.org/10.1175/1520-0493(1998)126<2673:TSAEOG>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Thorncroft, C. D., and M. Blackburn, 1999: Maintenance of the African easterly jet. Quart. J. Roy. Meteor. Soc., 125, 763786, https://doi.org/10.1002/qj.49712555502.

    • Search Google Scholar
    • Export Citation
  • Thorncroft, C. D., and K. Hodges, 2001: African easterly wave variability and its relationship to Atlantic tropical cyclone activity. J. Climate, 14, 11661179, https://doi.org/10.1175/1520-0442(2001)014<1166:AEWVAI>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Thorncroft, C. D., N. M. Hall, and G. N. Kiladis, 2008: Three-dimensional structure and dynamics of African easterly waves. Part III: Genesis. J. Atmos. Sci., 65, 35963607, https://doi.org/10.1175/2008JAS2575.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Torres, V. M., C. D. Thorncroft, and N. M. J. Hall, 2021: Genesis of easterly waves over the tropical eastern Pacific and the Intra-Americas Sea. J. Atmos. Sci., 78, 32633279, https://doi.org/10.1175/JAS-D-20-0389.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • University of Wyoming, 2020: Soundings. University of Wyoming Dept. of Atmospheric Science, accessed January 2020, http://weather.uwyo.edu/upperair/sounding.html.

    • Search Google Scholar
    • Export Citation
  • Wang, C. Z., 2002: Atlantic climate variability and its associated atmospheric circulation cells. J. Climate, 15, 15161536, https://doi.org/10.1175/1520-0442(2002)015<1516:ACVAIA>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wang, C. Z., and D. B. Enfield, 2001: The tropical Western Hemisphere warm pool. Geophys. Res. Lett., 28, 16351638, https://doi.org/10.1029/2000GL011763.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wang, C. Z., and D. B. Enfield, 2003: A further study of the tropical Western Hemisphere warm pool. J. Climate, 16, 14761493, https://doi.org/10.1175/1520-0442-16.10.1476.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Wang, J.-J., R. F. Adler, G. J. Huffman, and D. Bolvin, 2014: An updated TRMM composite climatology of tropical rainfall and its validation. J. Climate, 27, 273284, https://doi.org/10.1175/JCLI-D-13-00331.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Webster, P. J., 1994: The role of hydrological processes in ocean-atmosphere interactions. Rev. Geophys., 32, 427476, https://doi.org/10.1029/94RG01873.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Whitaker, J. W., and E. D. Maloney, 2018: Influence of the Madden–Julian oscillation and Caribbean low-level jet on east Pacific easterly wave dynamics. J. Atmos. Sci., 75, 11211141, https://doi.org/10.1175/JAS-D-17-0250.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Whitaker, J. W., and E. D. Maloney, 2020: Genesis of an east Pacific easterly wave from a Panama Bight MCS: A case study analysis from June 2012. J. Atmos. Sci., 77, 35673584, https://doi.org/10.1175/JAS-D-20-0032.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Whiteman, C. D., S. Zhong, X. Bian, J. D. Fast, and J. C. Doran, 2000: Boundary layer evolution and regional-scale diurnal circulations over the and Mexican Plateau. J. Geophys. Res., 105, 10 08110 102, https://doi.org/10.1029/2000JD900039.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Xie, S. P., and S. G. H. Philander, 1994: A coupled ocean‐atmosphere model of relevance to the ITCZ in the eastern Pacific. Tellus, 46A, 340350, https://doi.org/10.3402/tellusa.v46i4.15484.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Xie, S.-P., H. Xu, W. S. Kessler, and M. Nonaka, 2005: Air–sea interaction over the eastern Pacific warm pool: Gap winds, thermocline dome, and atmospheric convection. J. Climate, 18, 520, https://doi.org/10.1175/JCLI-3249.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Yanai, M., S. Esbensen, and J.-H. Chu, 1973: Determination of bulk properties of tropical cloud clusters from large-scale heat and moisture budgets. J. Atmos. Sci., 30, 611627, https://doi.org/10.1175/1520-0469(1973)030<0611:DOBPOT>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Zehnder, J. A., 1993: The influence of large-scale topography on barotropic vortex motion. J. Atmos. Sci., 50, 25192532, https://doi.org/10.1175/1520-0469(1993)050<2519:TIOLST>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Zhang, C. D., 1993: Large-scale variability of atmospheric deep convection in relation to sea-surface temperature in the tropics. J. Climate, 6, 18981913, https://doi.org/10.1175/1520-0442(1993)006<1898:LSVOAD>2.0.CO;2.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Zhang, C. D., and J. Ling, 2012: Potential vorticity of the Madden–Julian oscillation. J. Atmos. Sci., 69, 6578, https://doi.org/10.1175/JAS-D-11-081.1.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • Zhang, C. D., M. McGauley, and N. A. Bond, 2004: Shallow meridional circulation in the tropical eastern Pacific. J. Climate, 17, 133139, https://doi.org/10.1175/1520-0442(2004)017<0133:SMCITT>2.0.CO;2.

    • Crossref
    • 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, 10571072, https://doi.org/10.1175/BAMS-87-8-1057.

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

    • Crossref
    • Search Google Scholar
    • Export Citation
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Analysis of the Environment that Supports Easterly Waves over the Eastern Pacific and the Intra-Americas Sea in the Boreal Summer—A Potential Vorticity Perspective

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  • 1 aAtmospheric Sciences Research Center, University at Albany, State University of New York, Albany, New York
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Abstract

A review of the mean state over the tropical eastern Pacific (EPAC) and the Intra-Americas Sea (IAS) region is provided to assess the characteristics that impact the development and genesis of easterly waves (EWs). The EPAC–IAS region is characterized by complex topography, the Western Hemisphere warm pool, the ITCZ at 10°N, and predominant deep convection over the Panama Bight around 9°N, 78°W. A prominent easterly jet at 600 hPa of about 5.5 m s−1, is oriented approximately parallel to the Mexican coast. The jet is characterized by a strip of high potential vorticity (PV) on the cyclonic shear side and low PV on the anticyclonic side. This distribution of PV satisfies the necessary conditions for barotropic instability: the Charney–Stern condition, as well as the Fjørtoft condition. Together these conditions suggest the potential for barotropic growth of EWs over the EPAC region. The mean high PV region over the EPAC is created in association with two different populations of cloud/convection systems: stratiform and shallow, with the former being key for the creation of positive PV anomalies at midlevels. Evidence is also provided that suggests that the low PV region arises in association with sources of negative PV anomalies over the Sierra Madre region likely resulting from frequent dry convection. This is a key and novel result that is basic for the setting up of a negative meridional PV gradient and fundamental for the Charney–Stern condition associated with barotropic instability and growth of EWs.

Significance Statement

The tropical eastern Pacific is influenced by synoptic easterly waves that impact daily weather in the region and can trigger tropical cyclones. This research explores the nature of a midlevel jet that supports the development of easterly waves in this basin. The jet is established in association with moist convection over the ocean that leads to a midlevel potential vorticity maximum equatorward of the jet and, frequent dry convection over the Mexican Sierra Madre region that leads to a low-level potential vorticity minimum poleward of the jet. This finding highlights the need to better understand, and ultimately predict, these potential vorticity sources in order to better understand and predict the nature of the easterly wave developments in this region.

© 2022 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: Victor M. Torres, vtorrespuente@albany.edu

Abstract

A review of the mean state over the tropical eastern Pacific (EPAC) and the Intra-Americas Sea (IAS) region is provided to assess the characteristics that impact the development and genesis of easterly waves (EWs). The EPAC–IAS region is characterized by complex topography, the Western Hemisphere warm pool, the ITCZ at 10°N, and predominant deep convection over the Panama Bight around 9°N, 78°W. A prominent easterly jet at 600 hPa of about 5.5 m s−1, is oriented approximately parallel to the Mexican coast. The jet is characterized by a strip of high potential vorticity (PV) on the cyclonic shear side and low PV on the anticyclonic side. This distribution of PV satisfies the necessary conditions for barotropic instability: the Charney–Stern condition, as well as the Fjørtoft condition. Together these conditions suggest the potential for barotropic growth of EWs over the EPAC region. The mean high PV region over the EPAC is created in association with two different populations of cloud/convection systems: stratiform and shallow, with the former being key for the creation of positive PV anomalies at midlevels. Evidence is also provided that suggests that the low PV region arises in association with sources of negative PV anomalies over the Sierra Madre region likely resulting from frequent dry convection. This is a key and novel result that is basic for the setting up of a negative meridional PV gradient and fundamental for the Charney–Stern condition associated with barotropic instability and growth of EWs.

Significance Statement

The tropical eastern Pacific is influenced by synoptic easterly waves that impact daily weather in the region and can trigger tropical cyclones. This research explores the nature of a midlevel jet that supports the development of easterly waves in this basin. The jet is established in association with moist convection over the ocean that leads to a midlevel potential vorticity maximum equatorward of the jet and, frequent dry convection over the Mexican Sierra Madre region that leads to a low-level potential vorticity minimum poleward of the jet. This finding highlights the need to better understand, and ultimately predict, these potential vorticity sources in order to better understand and predict the nature of the easterly wave developments in this region.

© 2022 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: Victor M. Torres, vtorrespuente@albany.edu
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