In this lesson the learner will review and interpret data regarding the early performance of the National Water Model (versions 1.0 -1.2). Verification and evaluation of the National Water Model has been occurring since it went operational in August 2016. This lesson will review some of the main issues in model performance through early 2018, including some retrospective verification extending back to 2011. You will see how model performance has been improved as a result of verification. Among the topics addressed are peak flow timing errors, model bias and correlation, the impacts of basin calibration, inclusion of reservoirs, snowpack evolution, drainage in sandy soils, Quantitative Precipitation Forecasts (QPF), and time-lagged ensembles.