EAST CENTRAL FLORIDA RIP CURRENT PROGRAM

A rip current is a complex meteorological/oceanographic phenomenon that poses significant danger to beach gaers worldwide. Rip currents are narrow channels of water flow-ing out past the surf zone that can pull even strong swim-mers into deep water beyond the offshore sand bar. In Florida, rip current-related drownings averaged 21 per year during the period 1989-97. East central Florida averaged 4-5 rip current-related drownings per year during this period. An examination of east central Florida rip current data showed that large numbers of rescues occurred most often when long period ocean swells were impacting the beaches. This was in contrast to a study by Lushine (1991) which found that rip currents along the southeast Florida coast were mainly due to moderate onshore winds. The empirical forecasting technique developed by Lushine (LURCS) was adapted for use in east central Florida (ECFL LURCS). Available rip current data was used to calculate the Probability of Detection (POD), which is the percentage of events that are detected, and the False Alarm Ratio (FAR), which is the percentage of unverified warnings / forecasts. For events with a greater than normal number of rip current rescues, the POD was found to be slightly better than the 1994 national average POD for severe weather (Crowther and Halmstad 1995). A high FAR showed the need to further improve ECFL LURCS and become aggressive in verification. In May 1997, forecasters at the National Weather Service Forecast Office in Melbourne began issuing statements detailing the daily rip current threat based on a set of thresh-olds that were determined by this study. These statements are disseminated to the media and broadcast on NOAA Weather Radio. Points of contact at lifeguard stations are being utilized to provide feedback about the number of rip currents that occur after a statement is issued. This data will be used to refine the empirical forecasting scheme. 1