Large-Scale Storm Tide Modeling in the U.S. East Coast and the Bahamas during Hurricane Dorian, 2019

Hurricane Dorian (2019) was a destructive tropical cyclone that reached a Category 5 intensity before making landfall in the Bahamas. It destroyed the Grand Bahama Island and caused significant damage to U.S. Southeast Coast. We applied an unstructured grid large-scale SCHISM (Semi-implicit Cross-scale Hydroscience Integrated System Model) driven by NOAA’s weather model GFS (Global Forecast System) to predict storm surge and tide in the entire U.S. East Coast and the Bahamas during the hurricane. On each day beginning August 28, 2019, SCHISM was set up to run 5-day storm tide predictions to provide the most up-to-date forecasts. The model predicted a devastating storm tide (>3 m) along the coast of Grand Bahama Island which would result in life-threatening coastal inundation. This prediction was made on August 30, 2019, 48 hours in advance of Dorian’s direct hit to the Bahamas, and subsequently was verified to be consistent with the actual impacted areas captured by satellite images. The maximum storm tides along U.S. Southeast Coast (Florida, Georgia, South Carolina, North Carolina, and Virginia) were also accurately simulated 12-24 hours in advance, with an average error of less than 0.3 m and a timing difference less than 30 minutes against NOAA’s tidal gauge observations. We demonstrate the model’s potential capability to be used as an early warning tool or a live forecast system for the entire U.S. East Coast and the Bahamas during hurricane season.