SWAN (SimulatingWAves Nearshore) Model

The SWAN project in Southern Region is an experimental wave modeling project. The model is run at Southern Region Headquarters and at all Southern Region coastal forecast offices. The forecasts are produced using the Simulating WAves Nearshore (SWAN) wave model and the Real Time Ocean Forecast System Gulf Stream Forecasts.

The SWAN output is used as guidance to produce marine forecasts at the coastal forecast offices. NOTE: The SWAN output is only experimental and it may differ from the official forecast. For the official marine forecast graphics on the Web go to: http://www.weather.gov/forecasts/graphical/sectors/.

SWAN accounts for the following physics:
·         Wave propagation in time and space, shoaling, refraction due to current and depth, frequency shifting due to currents and non-stationary depth.
·         Wave generation by wind.
·         Three- and four-wave interactions.
·         Whitecapping, bottom friction and depth-induced breaking.
·         Dissipation.
·         Wave-induced set-up.
·         Propagation from laboratory up to global scales.
·         Transmission through and reflection (specular and diffuse) against obstacles.
·         Diffraction.

Please take the following survey to give feedback on the SWAN product : http://www.nws.noaa.gov/survey/nws-survey.php?code=SWNMO.

A description of the SWAN model output is available at : http://products.weather.gov/PDD/PDD%20NWPS%20Model%20Output%20060413.pdf.


The New Orleans/Baton Rouge Louisiana SWAN forecast for the open coastal waters area is located at:


Note that SWAN forecasts for the large tidal lakes and sounds may not be representative or available due to lack of bathymetric data at this scale.
Fortunately, high resolution bathymetric data is available on a smaller scale for the lakes and the sounds. This has allowed us to construct inner coastal area version of the SWAN model for the following areas:
·         Lake Pontchartrain
·         Lake Maurepas
·         Lake Borgne
·         Chandeleur Sound
·         Breton Sound
·         Mississippi Sound

The SWAN model forecast for the lakes and sound areas is located at:


The graphical output of the Regional SWAN run can be viewed at the link below:

Southern Region Headquarters SWAN Run
Southern Region Headquarters RTOFS Input Data

At the above link you will see 3-hourly forecast outputs for significant wave height in feet and peak wave direction, peak wave period, and significant swell height. In addition you will see the wind speed and direction used as input for the model.

The raw input data used for wind forcing can be downloaded at the following link:

Southern Region Headquarters SWAN Input Winds

The netCDF output of the model run can be downloaded at the following link:

Southern Region Headquarters SWAN netCDF Output

Below is a listing of the coastal forecast office participating in the SWAN Model experiment:
·         Brownsville, Texas
·         Corpus Christi, Texas
·         Houston/Galveston, Texas
·         Jacksonville, Florida
·         Key West, Florida
·         Lake Charles, Louisiana
·         Melbourne, Florida
·         Miami-South Florida, Florida
·         Mobile/Pensacola, Alabama/Florida
·         New Orleans/Baton Rouge, Louisiana
·         San Juan, Puerto Rico
·         Southern Region Headquarters, Texas
·         Tallahassee, Florida
·         Tampa Bay, Florida
NOTICE TO ALL USERS - This model is experimental and may not be available at all times.
The accuracy or reliability is not guaranteed or warranted. The data are provided 'as is' and
should not be used as the sole resource for decision making. Marine forecast guidance is best
interpreted by a professional meteorologist who is familiar with this particular modeling
system, including any model biases.

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