Finer Wind Field Resolution for NWS's Extra-Tropical Storm Surge Model

In the 1990's the National Weather Service's (NWS) Meteorological Development Laboratory (MDL) applied the Sea Lake and Overland Surges from Hurricanes (SLOSH) model to Extra-Tropical storms by (a) using the Global Forecast System (GFS) winds as input and (b) removing the computation of inundation based on surge in order to improve computational efficiency. The result was the Extra-Tropical Storm Surge (ETSS) model which is run operationally four times a day to predict storm surge along the U.S. East Coast, Gulf of Mexico, West Coast and all of the coasts of Alaska.

When the ETSS model was developed it used the finest resolution winds available. Since that time, the GFS model has begun producing wind forecasts on a 0.5 degree wind field, and will soon produce even finer wind fields. MDL recently upgraded the ETSS model to take advantage of the enhanced precision.

This paper will evaluate the benefits of that upgrade, particularly in sheltered regions such as the Chesapeake Bay, Long Island Sound, and Pamlico Sound, where the resolution of the wind field is thought to have the greatest impact on storm surge accuracy.