The St. Johns River Operational Forecast System: Evolution of an EFDC Model Application from Development to Operational Implementation

An operational forecast system using the Environmental Fluid Dynamics Code (EFDC) hydrodynamic model was implemented in the St. Johns River, Florida, and has been running operationally at NOAA for six years. In this paper, we look back on the evolution of this system, including its development, testing, validation, and operational implementation. As part of a program to examine water quality in the St. Johns River, the St. Johns River Water Management District (SJRWMD) developed this application of the EFDC hydrodynamic model to the lower St. Johns River. NOAA's Coastal Storms Program facilitated the transition of this model to NOAA for evaluation and operational implementation as the St Johns River Operational Forecast System (SJROFS). Operational Forecast Systems (OFSs) run at NOAA's National Ocean Service (NOS) and use the Coastal Ocean Modeling Framework (COMF), which employs standard procedures and formats for gathering inputs, formatting outputs, and running the models. Since the SJRWMD application used the EFDC model, the initial step in porting their model into COMF was to adjust the output into the Cooperative Ocean/Atmosphere Research Data Service-compliant netCDF format that NOS supports. The EFDC simulations were set up to perform hourly nowcasts (a simulation over the previous one hour up until the present time) and four forecasts (extending 36 hours into the future) per day using the standard COMF scripts. The final step in the transition to operational implementation was to evaluate the performance of the model application against standard NOS skill assessment criteria. A software tool was developed to perform this skill assessment with models in the COMF environment, and the St. Johns River model results were subsequently analyzed using this tool for different simulation scenarios (tides only, hindcasts, operational nowcasts, and forecasts). Skill assessment score tables were compiled for each location where observations were available using the software package, and these tables helped guide the best approach for transitioning the model to an operational environment. The SJROFS was made operational in October 2005, and comparisons between the model and available data are made publicly available on NOAA's CO-OPS website (http://tidesandcurrents.noaa.gov/). Skill assessment of the forecasts is also made on a regular basis to assess the system's on-going performance.