Ensemble-based sensitivity estimates for guidance in forecasting high seas

Our community's ability to estimate meteorological uncertainty information vastly exceeds our ability to usefully communicate uncertainty information. NRL Monterey and Fleet Numerical Meteorology and Oceanography Center (FNMOC) are exploring new methods to leverage ensemble guidance to help improve the quality and efficiency of human-based forecaster. Our hypothesis is that uncertainty guidance is of limited utility without information about why the uncertainty looks the way it does, especially in situations in which one must issue deterministic forecasts. We have implemented a demonstration project that provides forecasters with ensemble guidance of surface wave heights on the VACAPES operating area supplemented by sensitivity information that describes how aspects of the atmosphere earlier in the forecast period impact the waves at a particular location in space and time later in the forecast period. For example, a forecaster can view an ensemble plume plot at a particular location, select a forecast tau, and then view a plot of the sensitivity of the waves at that tau to atmospheric parameters (e.g. 500mb height, 850mb temperature) earlier in the forecast period. A description of the product will be given, along with objective forecast performance, the quality of forecasters issued by FNMOC forecasters, and lessons learned about training and dissemination.