Surge and Tide Operational Forecast System (STOFS)

This dataset collection describes the Surge and Tide Operational Forecast System (STOFS, formerly ESTOFS), which is a collaboration between the NOAA's Office of Coast Survey (OCS)/Coast Survey Development Lab (CSDL), University of Notre Dame, Virginia Institute of Marine Science and NOAA's National Centers for Environmental Prediction (NCEP).

The STOFS system runs on NCEP's central high performance computing system, the Weather and Climate Operational Supercomputing System 2 (WCOSS2), and is composed of three main products: STOFS-2D-Global, STOFS-3D-Atlantic, and STOFS-3D-Pacific.

STOFS-2D-Global is a two-dimensional depth averaged global component based on the ADvanced CIRCulation (ADCIRC) model core. STOFS-2D-Global runs four times daily producing numerical storm surge and tide model forecast guidance globally out to 180 hours. The model is forced by real time output of winds and pressure from the NCEP Global Forecast System (GFS). The domain of the operational STOFS-2D-Global forecast guidance covers the entire globe, including the floodplain of the coastal U.S., the Caribbean area surrounding Puerto Rico, and Alaska.

STOFS-3D-Atlantic is a three-dimensional (3D) model component for the Atlantic basin (STOFS-3D-Atl) based on the Semi-implicit Cross-scale Hydroscience Integrated System Model (SCHISM) core. STOFS-3D-Atl runs daily to provide one day of nowcast and four days of water level and surface current forecast guidance. STOFS-3D-Atl makes use of outputs from the National Water Model (NWM) to include inland hydrology and extreme precipitation effects on coastal flooding, forecast guidance from the NCEP Global Forecast System (GFS) and High-Resolution Rapid Refresh (HRRR) model as the surface meteorological forcing, the combined tidal and subtidal water level, and three-dimensional water temperature, salinity, and currents from the NCEP Global Real-Time Ocean Forecast System (G-RTOFS) as the open ocean boundary forcing.

STOFS-3D-Pacific is a three-dimensional (3D) model component for the Pacific basin (STOFS-3D-Pac) based on the Semi-implicit Cross-scale Hydroscience Integrated System Model (SCHISM) core. STOFS-3D-Pacific runs daily to provide one day of nowcast and two days of water level and surface current forecast guidance. STOFS-3D-Pac makes use of outputs from the National Water Model (NWM), Copernicus Global Flood Awareness System (GloFAS), USGS, and Canadian stream gauge data to include inland hydrology and extreme precipitation effects on coastal flooding; forecast guidance from the NCEP Global Forecast System (GFS) and High-Resolution Rapid Refresh (HRRR) model as the surface meteorological forcing; the tidal water level and currents from the TPXO9 tidal database; and the subtidal water level, and subtidal three-dimensional water temperature, salinity, and currents from the NCEP Global Real-Time Ocean Forecast System (G-RTOFS) with the subtidal water level from G-RTOFS and Copernicus Absolute Dynamic Topography (ADT) satellite altimetry observation as the open ocean boundary forcing.

NOAA utilizes the STOFS 2D (Global) and 3D (Atlantic and Pacific) systems to generate IHO S-104 water level and S-111 surface current forecast guidance for marine navigation

Finally, the STOFS Reanalysis was created by building on NOAA's STOFS-3D-Atlantic forecast (STOFS-3D-Atl) and implementing data assimilation using an efficient Ensemble Optimal Interpolation (EnOI) to assimilate CO-OPS water level gauges along the east and Gulf coasts. A 26-year reanalysis was then conducted using this tool, spanning from 2000 to 2025, with each year being simulated separately but with a one-month overlap between years (i.e. 2001 simulation starts from Dec 1, 2000). This database represents the first ever physically based simulation for total water levels.

STOFS provides operational nowcast and forecast guidance for water level, water currents, water temperature, and salinity. This guidance supports a wide range of user communities, including disaster mitigation, marine navigation, emergency response, search and rescue, ecosystem health, and pollution transport. The NOAA National Weather Service (NWS) and U.S. Coast Guard Search and Rescue continuously rely on STOFS nowcast/forecast guidance for their operational requirements (operational forecasts, operational search and rescue, etc.). Furthermore, STOFS model output is being provided in S-100 Universal Hydrographic Model formats (e.g. S-104 water levels and S-111 surface currents) for NOAA's Precision Marine Navigation program.

Entity attribute information can be found in the individual STOFS products child items list in the "Child Items" tab.

These products are:

Surge and Tide Operational Forecast System (STOFS) - 2D

Data Set Surge and Tide Operational Forecast System (STOFS) - 3D

Data Set Surge and Tide Operational Forecast System (STOFS) - 3D Reanalysis

STOFS model output is NOT total water level guidance. Actual water levels can be significantly higher than forecast due to waves and other components not presently included in STOFS.

Please check with your regional National Weather Service forecast office for the official water level forecast.

Accuracy is determined by running comparisons of the model against observations, and quantifying the precision (e.g. unbiased RMSE) and bias of the model.

Quantified by comparing the model mesh grid to the real world spatial reference system (e.g. WGS84).

Quantified by comparing the bathymetry/topography underlying the model with observed raw surveys of bathymetry/topography and quantifying the total propagated uncertainty (TPU) during transformation from the raw survey's vertical datum to the vertical datum used by the model.

Bias is determined by running comparisons of the model against observations, and quantifying the bias of the model. Bias corrections are conducted in post-processing for STOFS-2D-Global and in pre-processing for STOFS-3D-Atlantic.

Both model and observation data are converted into the xGEOID20b (for STOFS-3D) datum and local mean sea level (LMSL) datum (for STOFS-2D) using NOAA's VDatum tool for direct comparison. The mesh bathymetry near the coast is converted to xGEOID20b using the VDatum software to standardize the vertical datum. A combination of different Digital Elevation Model (DEM) sources is used for mesh generation and bathymetry.

Precision is determined by running comparisons of the model against observations, and quantifying the precision (e.g. unbiased RMSE) of the model.