Standards for Hydrodynamic Model Assessment Skill assessment is an objective measurement of how well the model nowcast or forecast guidance does when compared to observations. NOS requires operational modeling systems to be assessed for skill in adherence to NOS standards. Skill assessment statistics that quantify model performance are calculated from significant model variables according to prescribed routines. In order for a nowcast/forecast system to be accepted operationally the skill assessment statistics must meet prescribed targets as described by NOS standards (see documentation). A skill assessment software package has been designed to perform skill assessment for water levels, currents, temperature, and salinity for different model systems in both tidally-dominated and non-tidal regions. Documentation of the skill assessment software is available which describes the analysis and programs in further detail and is available for download. References Hess, K. W., T. F. Gross, R. A. Schmalz, J. G. W. Kelley, F. Aikman, III, E. Wei, and M. S. Vincent, 2003: NOS standards for evaluating operational nowcast and forecast hydrodynamic model systems, NOAA Technical Report NOS CS 17, 47 pp. Zhang, A-J., K.W. Hess, E. Wei, and E. Myers, 2006: Implementation of model skill assessment software for water level and current in tidal regions, NOAA Technical Report NOS CS 24, 61 pp.