Support by Ken Mitchell, Eric Rogers, and the Environmental Modeling Center (NCEP/EMC) is deeply appreciated. We thank Pavel Groisman for facilitating the correction terms for winter precipitation and Evgeney Yarosh for making them available in an adequate format. Comments by Roni Avissar are also appreciated. The comments of three anonymous reviewers helped clarify several aspects of the paper. This work was partially supported by NOAA Grants NA76GP0291 and NA76GP0479.
Alexander, M. A., and S. D. Schubert, 1990: Regional earth–atmosphere energy balance estimates based on assimilations with a GCM. J. Climate,3, 5–14.
Berbery, E. H., E. M. Rasmusson, and K. E. Mitchell, 1996: Studies of North American continental scale hydrology using Eta Model forecast products. J. Geophys. Res.,101 (D3), 7305–7319.
Betts, A. K., J. H. Ball, A. C. J. Beljaars, M. J. Miller, and P. Viterbo, 1996: The land surface–atmosphere interaction: A review based on observational and global modeling perspectives. J. Geophys. Res.,101 (D3), 7209–7225.
——, F. Chen, K. E. Mitchell, and Z. I. Janjić, 1997: Assessment of the land surface and boundary layer models in the two operational versions of the NCEP Eta Model using FIFE data. Mon. Wea. Rev.,125, 2896–2916.
——, P. Viterbo, A. Beljaars, H.-L. Pan, S.-H. Hong, M. Goulden, and S. Wofsy, 1998a: Evaluation of the land–surface interaction in the ECMWF and NCEP/NCAR reanalysis models over grassland (FIFE) and Boreal forest (BOREAS). J. Geophys. Res.,103, 23 079–23 085.
——, ——, and E. Wood, 1998b: Surface energy and water balance for the Arkansas–Red River basin from the ECMWF reanalysis. J. Climate,11, 2881–2897.
Black, T. L., 1994: The new NMC mesoscale Eta Model: Description and forecast examples. Wea. Forecasting,9, 265–278.
Chen, F., K. Mitchell, and J. Schaake, 1996: Modeling of land surface evaporation by four schemes and comparison with FIFE observations. J. Geophys. Res.,101 (D3), 7251–7268.
Climate Prediction Center, 1996a: Winter weather review. Weekly Weather Crop Bulletin, Vol. 83, No. 11, 24 pp. [Available from Climate Prediction Center, W/NP52, Attn: Weekly Weather and Crop Bulletin, NOAA/NWS/NCEP, 4700 Silver Hill Road, Stop 9910, Washington, DC 20233.].
——, 1996b: Spring weather review. Weekly Weather Crop Bulletin, Vol. 83, No. 23, 28 pp. [Available from Climate Prediction Center, W/NP52, Attn: Weekly Weather and Crop Bulletin, NOAA/NWS/NCEP, 4700 Silver Hill Road, Stop 9910, Washington, DC 20233.].
——, 1997: Winter weather review. Weekly Weather Crop Bulletin, Vol. 84, No. 10, 16 pp. [Available from Climate Prediction Center, W/NP52, Attn: Weekly Weather and Crop Bulletin, NOAA/NWS/NCEP, 4700 Silver Hill Road, Stop 9910, Washington, DC 20233.].
Coughlan, M., and R. Avissar, 1996: The Global Energy and Water Cycle Experiment (GEWEX) Continental-scale International Project (GCIP): An overview. J. Geophys. Res.,101 (D3), 7139–7147.
Dunn, L. B., and J. D. Horel, 1994: Prediction of central Arizona convection. Part II: Further examination of the Eta Model forecasts. Wea. Forecasting,9, 508–521.
Ehrendorfer, M., M. Hantel, and Y. Wang, 1994: A variational modification algorithm for three-dimensional mass flux non-divergence. Quart. J. Roy. Meteor. Soc.,120, 655–698.
Giorgi, F., S. W. Hosteler, and C. Shields Brodeur, 1994: Analysis of the surface hydrology in a regional climate model. Quart. J. Roy. Meteor. Soc.,120, 161–183.
Groisman, P. Ya., and D. R. Legates, 1994: The accuracy of the United States precipitation data. Bull. Amer. Meteor. Soc.,75, 215–227.
——, D. R. Easterling, R. G. Quayle, V. S. Golubev, A. N. Krenke, and A. Yu. Mikhailov, 1996: Reducing biases in estimates of precipitation over the United States: Phase 3 adjustments. J. Geophys. Res.,101 (D3), 7185–7195.
Gutowski, W. J., Y. Chen, and Z. Ötles, 1997: Atmospheric water vapor transport in NCEP–NCAR reanalyses: Comparison with river discharge in the central United States. Bull. Amer. Meteor. Soc.,78, 1957–1969.
Helfand, H. M., and S. D. Schubert, 1995: Climatology of the simulated 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., K. C. Mo, and S. D. Schubert, 1996: The moisture budget of the central United States in spring as evaluated in the NCEP/NCAR and the NASA/DAO reanalyses. Mon. Wea. Rev.,124, 939–963.
——, Y. Yao, E. S. Yarosh, J. E. Janowiak, and K. C. Mo, 1997: Influence of the Great Plains low-level jet on summertime precipitation and moisture transport over the central United States. J. Climate,10, 481–507.
International GEWEX Project Office, 1995: Major activities plan for 1996, 1997, and outlook for 1998 for GCIP. IGPO Publ. Series 16, Int. GEWEX Project Office, Washington, DC, 246 pp. [Available from 1010 Wayne Avenue, Suite 450, Silver Springs, MD 20910.].
Janjić, Z. I., 1990: The step-mountain coordinate: Physical package. Mon. Wea. Rev.,118, 1429–1443.
——, 1994: The step-mountain Eta coordinate model: Further developments of the convection, viscous sublayer, and turbulence closure schemes. Mon. Wea. Rev.,122, 927–945.
Kanamitsu, M., and S. Saha, 1996: Systematic tendency error in budget calculations. Mon. Wea. Rev.,124, 1145–1160.
La Rue, J. A., and R. J. Younkin, 1963: Large-scale precipitation volumes, gradients and distribution. Mon. Wea. Rev.,91, 393–401.
Lin, Y., K. E. Mitchell, E. Rogers, and G. J. DiMego, 1995: Impact of satellite moisture observations on forecasts made by NMC’s Eta model. Preprints, 14th Conf. on Weather Analysis and Forecasting, Dallas, TX, Amer. Meteor. Soc., 301–302.
Mesinger, F., 1996: Improvements in quantitative precipitation forecasts with the Eta regional model at the National Centers for Environmental Prediction: The 48-km upgrade. Bull. Amer. Meteor. Soc.,77, 2637–2649.
——, and T. L. Black, 1992: On the impact on forecast accuracy of the step-mountain (Eta) vs. sigma coordinate. Meteor. Atmos. Phys.,50, 47–60.
——, Z. I. Janjić, S. Ničković, D. Gavrilov, and D. G. Deaven, 1988:The step-mountain coordinate: Model description and performance for cases of alpine lee cyclogenesis and for a case of Appalachian redevelopment. Mon. Wea. Rev.,116, 1493–1518.
Peixoto, J. P., and A. H. Oort, 1992: Physics of Climate. American Institute of Physics, 520 pp.
Rasmusson, E. M., 1967: Atmospheric water vapor transport and the water balance of North America. Part I: Characteristics of the water vapor flux field. Mon. Wea. Rev.,95, 403–426.
——, 1968: Atmospheric water vapor transport and the water balance of North America. Part II: Large-scale water balance investigations. Mon. Wea. Rev.,96, 720–734.
——, and K. C. Mo, 1996: Large-scale atmospheric moisture cycling as evaluated from global NMC analysis and forecast products. J. Climate,9, 3276–3297.
Roads, J., S. Chen, A. Guetter, and K. Georgakakos, 1994: Large-scale aspects of the United States hydrologic cycle. Bull. Amer. Meteor. Soc.,75, 1589–1610.
——, ——, M. Kanamitsu, and H. Juang, 1998: Vertical structure of humidity and temperature budget residuals over the Mississippi River basin. J. Geophys. Res.,103 (D4), 3741–3759.
Rogers, E., T. L. Black, D. G. Deaven, and G. J. DiMego, 1996: Changes to the operational early Eta analysis/forecast system at the National Centers for Environmental Prediction. Wea. Forecasting,11, 391–413.
Ropelewski, C. F., and E. S. Yarosh, 1998: The observed mean annual cycle of moisture budgets over the central United States (1973–92). J. Climate,11, 2180–2190.
Rosen, R. D., D. A. Salstein, and J. P. Peixoto, 1979: Variability in the annual fields of large-scale atmospheric water vapor transport. Mon. Wea. Rev.,107, 26–37.
Trenberth, K. E., 1991: Climate diagnostics from global analyses: Conservation of mass in ECMWF analyses. J. Climate,4, 707–722.
——, and C. J. Guillemot, 1995: Evaluation of the global atmospheric moisture budget as seen from analyses. J. Climate,8, 2255–2272.
Wallace, J. M., 1975: Diurnal variations in precipitation and thunderstorm frequency over the conterminous United States. Mon. Wea. Rev.,103, 406–419.
Wang, M., and J. Paegle, 1996: Impact of analysis uncertainty upon regional atmospheric moisture flux. J. Geophys. Res.,101 (D3), 7291–7303.
Yarosh, E. S., C. F. Ropelewski, and K. E. Mitchell, 1996: Comparisons of humidity observations and Eta Model analyses and forecasts for water balance studies. J. Geophys. Res.,101 (D18), 23 289–23 298.
Zhao, Q., T. L. Black, and M. E. Baldwin, 1997: Implementation of the cloud prediction scheme in the Eta Model at NCEP. Wea. Forecasting,12, 697–712.