The 1993 summer rainfall over the Midwestern United States caused major flo
oding in the Upper Mississippi and Lower Missouri River basins. In this pap
er, a monthly comparative study of the analysis products from the European
Centre for Medium-Range Weather Forecasts (ECMWF) with observations is cond
ucted for the period September 1992 to August 1993, The model products incl
ude the ECMWF analysis for the Tropical Ocean and Global Atmosphere (TOGA)
project and ECMWF reanalysis (ERA) project. Overall, the large-scale hydrol
ogical components (precipitation, evaporation, precipitable water, surface
temperature, and relative humidity) appear partially improved from TOGA to
ERA. Some internal inconsistencies exist in the assimilation of the ERA dat
a from October 1992 to March 1993, in association with the dramatic prevale
nce of large-scale moisture divergence at 0000 UT, The separation of moistu
re flux into meridional and zonal components indicates that the correct des
cription of the meridional moisture flow is of crucial importance for simul
ation of anomalously wet conditions. While the spatially averaged monthly f
ields in ERA and TOGA are reasonable (in particular, the models maintain ve
ry good mean flow), the fine-scale extremes are less accurate. The models d
o not reproduce observed mesoscale convective complexes due to limitations
on resolution and the parameterization of precipitation processes, The new
soil hydrology and boundary layer schemes of ERA work better in warm months
but with no consistent improvement over TOGA, The terrestrial water budget
in ERA is unrealistic, with accumulated model runoff being largely deviate
d from the observed stream-flow, In addition to modeling internal water bal
ance, the lack of the routing procedure and the low spatial resolution of s
urface hydrology are the other major reasons for this imbalance.