We wish to thank the NCEP–NCAR Reanalysis Team for the Reanalysis data and David Easterling of the National Climatic Data Center, Asheville, for the Mexican precipitation data. The authors are also indebted to John Janowiak, Gerry Bell, Vern Kousky, Gene Rasmusson, Chet Ropelewski, Ants Leetmaa, and Kingtse Mo for insightful discussions. This work was partially supported by the NOAA Office of Global Programs under the Pan American Climate Studies (PACS) project and the GEWEX Continental-Scale International Project (GCIP) and by Interagency Agreement No. S-41367-F under the authority of NASA/GSFC.
Arkin, P. A., 1982: The relationship between interannual variability in the 200-mb tropical wind field and the southern oscillation. Mon. Wea. Rev.,110, 1393–1404.
Bonner, W. D., 1968: Climatology of the low-level jet. Mon. Wea. Rev.,96, 833–850.
Carleton, A. M., 1986: Synoptic-dynamic character of “bursts” and “breaks” in the southwest U.S. summer precipitation singularity. J. Climatol.,6, 605–623.
Charba, J. P., A. W. Harrell III, and A. C. Lackner III, 1992: A monthly precipitation amount climatology derived from published atlas maps: Development of a digital database. TDL Office Note 92-7, 20 pp. [Available from TDL Office, NOAA, U.S. Department of Commerce, 1325 East–West Hwy., Silver Spring, MD 20910.].
Cressman, G. P., 1959: An operational objective analysis system. Mon. Wea. Rev.,87, 367–374.
Dhar, O. N., P. R. Rakhecha, and B. N. Mandal, 1980: Does the early or late onset of the monsoon provide any clue to the subsequent rainfall during the monsoon season? Mon. Wea. Rev.,108, 1069–1072.
Douglas, M. W., R. A. Maddox, K. Howard, and S. Reyes, 1993: The Mexican Monsoon. J. Climate,6, 1665–1677.
Glahn, H. R., T. L. Chambers, W. S. Richardson, and H. P. Perrotti, 1985: Objective map analysis for the local AFOS MOS Program. NOAA Tech. Memo. NWS TDL 75, 34 pp. [Available from NOAA, U.S. Department of Commerce. 1325 East–West Hwy., Silver Spring, MD 20910.].
Helfand, H. M., and S. D. Schubert, 1995: Climatology of the Great Plains low-level jet and its contribution to the continental moisture budget of the United States. J. Climate,8, 784–806.
Higgins, R. W., J. E. Janowiak, and Y. Yao, 1996: A Gridded Hourly Precipitation Data Base for the United States (1963–1993). NCEP/Climate Prediction Center Atlas 1, 47 pp.
——, Y. Yao, E. S. Yarosh, J. E. Janowiak, and K. C. Mo, 1997a: Influence of the Great Plains low-level jet on summertime precipitation and moisture transport over the central United States. J. Climate,10, 481–507.
——, ——, and X. Wang, 1997b: Influence of the North American Monsoon System on the United States summer precipitation regime. J. Climate,10, 2600–2622.
——, K. C. Mo, and Y. Yao, 1998: Interannual variability of the United States summer precipitation regime with emphasis on the southwestern monsoon. J. Climate,11, 2582–2606.
Janowiak, J. E., A. Gruber, C. R. Kondragunta, R. E. Livezey, and G. J. Huffman, 1998: A comparison of the NCEP–NCAR Reanalysis Precipitation and the GPCP Raingauge–Satellite combined dataset with observational error considerations. J. Climate,11, 2960–2979.
Johnson, A. M., 1976: The climate of Peru, Bolivia and Ecuador. World Survey of Climatology. Vol. 12, Climates of Central and South America, W. Schwerdtfeger and H. E. Landsberg, Eds., Elsevier, 147–218.
Kalnay, E., and Coauthors, 1996: The NCEP–NCAR Reanalysis Project. Bull. Amer. Meteor. Soc.,77, 437–471.
Kiladis, G. N., and H. Van Loon, 1988: The Southern Oscillation. Part VII: Meteorological anomalies over the Indian and Pacific sectors associated with extremes of the oscillation. Mon. Wea. Rev.,116, 120–136.
Kousky, V. E., and C. F. Ropelewski, 1997: The Tropospheric Seasonally Varying Mean Climate over the Western Hemisphere (1979–1995). NCEP/Climate Prediction Center Atlas 3, 135 pp.
Livezey, R. E., 1995: Field intercomparison. An Analysis of Climate Variability Applications of Statistical Techniques, H. Von Storch and A. Navara, Eds., Springer-Verlag, 159–176.
Meehl, G. A., 1994: Influence of the land surface in the Asian summer monsoon: External conditions versus internal feedbacks. J. Climate,7, 1033–1049.
——, and W. A. Washington, 1988: A comparison of soil moisture sensitivity in two global climate models. J. Atmos. Sci.,45, 1476–1492.
Mo, K. C., J. N. Paegle, and R. W. Higgins, 1997: Atmospheric processes associated with summer floods and droughts in the central United States. J. Climate,10, 3028–3046.
Mock, C. J., 1996: Climatic controls and spatial variations of precipitation in the western United States. J. Climate,9, 1111–1125.
Okabe, I. T., 1995: The North American Monsoon. Ph.D. dissertion, University of British Columbia, 146 pp.
Parrish, D. F., and J. C. Derber, 1992: The National Meteorological Center’s spectral statistical interpolation analysis system. Mon. Wea. Rev.,120, 1747–1763.
Ramage, C. S., 1971: Monsoon Meteorology. Academic Press, 391 pp.
Ropelewski, C. F., and M. S. Halpert, 1986: North American precipitation and temperature patterns associated with El Niño–Southern Oscillation (ENSO). Mon. Wea. Rev.,114, 2352–2362.
——, and ——, 1996: Quantifying southern oscillation–precipitation relationships. J. Climate,9, 1043–1059.
Smith, T. M., R. W. Reynolds, R. E. Livezey, and D. C. Stokes, 1996:Reconstruction of historical sea surface temperatures using empirical orthogonal functions. J. Climate,9, 1403–1420.
Stensrud, D. J., R. L. Gall, S. L. Mullen, and K. W. Howard, 1995:Model climatology of the Mexican monsoon. J. Climate,8, 1775–1794.
Tang, M., and E. R. Reiter, 1984: Plateau monsoons of the Northern Hemisphere: A comparison between North America and Tibet. Mon. Wea. Rev.,112, 617–637.
Wallace, J. M., 1975: Diurnal variations in precipitation and thunderstorm frequency over the conterminous United States. Mon. Wea. Rev.,103, 406–419.
Webster, P. J., 1987: The elementary monsoon. Monsoons, J. S. Fein and P. L. Stephens, Eds., John Wiley and Sons, 3–32.
——, and S. Yang, 1992: Monsoon and ENSO: Selectively interactive systems. Quart. J. Roy. Meteor. Soc.,118, 877–926.