Input for the wave model is obtained from an atmospheric model. This image is derived from the Analysis image from the atmospheric model, which depicts the current state of the atmosphere and is constructed using confirmed wind observations from satellites, ground stations, buoys, weather balloons and a variety of other sources. That's right, it uses confirmed wind speed and direction data. The wave models take the confirmed wind data from the analysis image of the atmospheric model and use it to estimate the winds effect on open ocean waters, projecting seas heights, headings, and in some cases, swell propagation. In this example notice that high sea areas and associated swell vectors are displayed simultaneously.
Seas are highest in the center of the fetch area and heading east.
The Scripps Research Institute Charts produced by wave models are fairly easy to read. The Sea Height chart typically uses either color-coding or circles to indicate concentrations of similar sized seas. But for surf forecasting purposes, a 12-hour average sample seems to be sufficient, if not better, than a shorter time period because it smoothes out anomalous spikes. Sea heading is indicated by a barb or arrow that points in the direction the sea is moving and is commonly called a 'sea vector' . Though a good guide in the center of high seas and fetch areas, sea vectors can become less meaningful once the seas escape their source.