The Extratropical Surge and Tide Operational Forecast System for the Atlantic (ESTOFS Atlantic) provides users with nowcasts (analyses of near present conditions) and forecast guidance of water level conditions for the Atlantic and Gulf coasts. The forecast outputs includes water levels caused by the combined effects of storm surge and tides, by astronomical tides alone, and by sub-tidal water levels (isolated storm surge) out to 180 hours. The hydrodynamic model employed by ESTOFS is the ADvanced CIRCulation (ADCIRC) finite element model. The unstructured grid used by ESTOFS Atlantic consists of 254,565 nodes and 492,179 triangular elements. Coastal resolution generally averages about 3 km. The open-ocean boundary is located at the 60 W meridian, where harmonic tidal constituents from the global tidal model TPXO 6.2 are used to specify tidal water surface fluctuations, while tidal potential forcing is applied within the interior of the domain. ESTOFS output files are provided in two formats: structured GRIB2 files for the contiguous U.S. (2.5 km resolution) and for Puerto Rico (1.25 km resolution) grids, and unstructured NetCDF files on the native ESTOFS finite element grid. NetCDF output is also provided at observation station locations. GRIB2 files are created for hourly predictions during each forecast cycle, consisting of hourly records of combined water level (surge with tide), harmonic tidal prediction (astronomical tides), and sub-tidal water levels (the isolated surge). NetCDF files contain an entire run cycle, and consist of the hourly combined water level over the native ESTOFS grid, or six-minute combined water level records at observation station locations.

ESTOFS web page:
Storm Surge