Port Isabel Surf Stats

The rose diagram describes the range of swells directed at Port Isabel over a normal April. It is based on 3360 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind and surf right at the shore so we have chosen the best grid node based on what we know about Port Isabel. In the case of Port Isabel, the best grid node is 22 km away (14 miles). The rose diagram illustrates the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing but lacks direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These happened only 11% of the time. Green and yellow show increasing swell sizes and red illustrates highest swells greater than >3m (>10ft). In each graph, the area of any colour is proportional to how frequently that size swell happens. The diagram suggests that the dominant swell direction, shown by the longest spokes, was E, whereas the the dominant wind blows from the ESE. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Port Isabel and away from the coast. We group these with the no surf category of the bar chart. To avoid confusion we don't show these in the rose diagram. Because wind determines whether or not waves are surfable at Port Isabel, you can select a similar diagram that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. During a typical April, swells large enough to cause good for surfing waves at Port Isabel run for about 89% of the time.

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