Forecasting Significant Wave Height in a Coastal Estuary

As part of a NOAA CSTAR funded project, the Florida Institute of Technology is working with the National Centers for Environmental Prediction (NCEP) Environmental Modeling Center and National Weather Service (NWS) offices in Melbourne and Miami Florida to extend the Nearshore Wave Prediction System (NWPS) into the coastal estuary. In the work presented here, we focus on the Indian River Lagoon (IRL), which is on the order of 200 km long and 8 km across at its widest. Given its elongated and narrow configuration, the IRL is extremely fetch limited and thus small errors in the wind magnitude, direction and/or duration can have a significant impact on forecast set-up and wave heights. Using output from our in-house unstructured configuration of the Simulating Waves Nearshore model (SWAN) and ADvanced CIRCulation model (ADCIRC) as a proxy for the ‘truth', we assess the utility of applying a simple wave height parameterization as a means by which to identify potentially high impact wind forcing from an ensemble. Here we apply different wind forcings, mined from select ensembles within NCEP's Short Range Ensemble Forecast (SREF) model suite, for a strong cold front passage in east-central Florida during the past spring. In addition to driving the numerical simulations, the coarse resolution wind forcing will be used along with a direction-dependent fetch estimate as significant wave height (Hs) parameterization inputs. Histograms of the input wind forcing and parameterized Hs will be presented along with time series of peak Hs and its distribution within the IRL.