Storm surge probability forecasts for Hurricane Ike

The National Hurricane Center (NHC), in cooperation with the NWS Meteorological Development Laboratory, began the operational issuance of tropical cyclone storm surge probability products during the 2009 hurricane season to satisfy the increasing user need for probability-based decision-support products. Issued when U.S. hurricane watches or warnings are in effect, these products are based on the NHC official track and intensity forecasts but incorporate historical track and intensity errors, as well as variability in the radius of maximum winds. “Exceedance height” products, which indicate the storm surge height that has a certain probability of being exceeded at a location over the next 3 days, are also available on an experimental basis in increments of 10% from 10% to 90%. At this time, the utility of these products is somewhat uncertain, and their interpretation has been complicated for meteorologists and emergency managers alike. The purpose of this study is to provide an evaluation of the exceedance height products for Hurricane Ike (2008) by comparing the storm surge probability forecasts at various lead times with the observed or measured storm surge. This type of information could prove useful in improving storm surge forecasts and in the development of a tropical cyclone storm surge warning, which is currently being investigated by the National Weather Service.