A high-resolution Numerical Weather Prediction (NWP) model was used to forecast the daily onset of the central Florida East Coast Sea Breeze (ECSB) during two warm seasons, May-August 1999 and May-September 2000. The study area focuses on the Kennedy Space Center (KSC), Cape Canaveral Air Force Station (CCAFS) and surrounding environs, including barrier islands, Merritt Island, mainland Florida and the Indian River, Banana River and Mosquito lagoons. The onset of the ECSB is closely monitored over the region as it significantly alters the low-level wind speed and direction and provides a focusing mechanism for convection during the Florida warm season.

The Regional Atmospheric Modeling System (RAMS) is run operationally at KSC/CCAFS using four nested grids. The innermost grid is run at 1.25-km horizontal grid spacing with 36 vertical levels to generate prognostic wind and temperature fields in support of operations on the Eastern Range in the event of an accidental hazardous material release or an aborted vehicle launch. Initialization data are obtained from a regional forecast model and both local and national operationally available observational data. Validation of the sea breeze onset for the two warm seasons was made by comparing the forecast surface wind field to wind observations from a network of 12 KSC/CCAFS wind towers on the coastal barrier islands, Merritt Island and the Florida mainland. Daily observed sea breezes were identified by surface observations, fine-line echoes in regional weather radar data and cloud patterns in visible imagery from the Geostationary Operational Environmental Satellite, GOES-8.

Results of the sea breeze modeling/validation study show that RAMS is an excellent predictor of the ECSB within the KSC/CCAFS wind-tower network. The 1200 UTC initialization of RAMS had a 98% probability of detecting the ECSB during the 1999 and 2000 warm seasons. Root-mean-square (RMS) timing errors associated with the forecast onset were between 1.5 and 2.1 hours, with a negligible bias. It was also noted that the 1.25-km configuration of RAMS produced superior ECSB forecasts compared to a 5-km configuration of RAMS, resulting from an improved characterization of interactions between sea and river breezes.