Coastal Storm Surge Operational Forecast Development at the National Ocean Service

Coastal water levels are subject to tidal variability, seasonal and climatic changes, and short-term weather-induced signals. Sophisticated computer modeling systems are required to account for a wide spectrum of physical factors that contribute to the total water level, and inundation extent in the coastal zone. In particular, rapid flooding associated with tropical and extratropical cyclones is a major threat to life, property, navigation, economy and environment along the coasts. Since 2012, National Ocean Service’s Coast Survey Development Laboratory (CSDL) is developing storm surge operational forecasting systems (OFS) to assist coastal forecasters with better guidance in advance of, and during the storms. After the storm had passed, similar models are used to reconstruct the observed flooding in order to assist recovery efforts, and to further tune model parameters.

One of CSDL products is a deterministic extra-tropical surge and tide forecast system (ESTOFS), which provides up to 7-days guidance, 4 times a day, for the Atlantic Domain (US East and Gulf Coast and the Caribbean), Pacific Domain (US West Coast and Hawaii), and Micronesia Domain (US territories from Palau to Marianas and Marshall Islands). Data assimilating, on-demand hurricane forecast system (HSOFS) has been developed for the National Hurricane Center to assist with short-term ensemble guidance. Similar framework is used to develop high-accuracy named storm event model (NSEM) for a coupled ocean, wave, riverine, and atmospheric reanalysis of major landfalling storms.

CSDL is working with National Weather Service, external agencies, and academia on constantly improving the quality of our forecast and hindcast products. We will discuss recent upgrades and ongoing development in storm surge systems, with emphasis on skill assessment and metrics for a variety of applications, from a continuously running OFS guidance to retrospective analysis and hindcasts.