The National Centers for Environmental Prediction North American Regional Reanalysis (NARR) output is passed through a broadband filter to determine the normalized covariances that describe the variance of the atmospheric water cycle at diurnal and annual time scales. The balance between precipitation, evaporation, precipitable water tendency, and moisture flux convergence holds at each time scale, allowing 100% of each variable's temporal variance to be described by its covariance with other water cycle components in the same variance category. Additional insight into internal dynamics of the reanalysis system is drawn from NARR's ability to individually track vapor and liquid water convergence, as well as the processes by which precipitation assimilation is achieved. NARR's performance differs greatly between the annual and diurnal time scales, owing largely to the scale of precipitation assimilation in various portions of the domain.