Statistiques de Surf de Petatlan

The figure describes the variation of swells directed at Petatlan through a typical August, based on 3472 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the shore so we have chosen the optimum grid node based on what we know about Petatlan. In this particular case the best grid node is 26 km away (16 miles). The rose diagram shows the distribution of swell directions and swell sizes, 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 occurred only 1.0% of the time. Green and yellow show increasing swell sizes and red represents highest swells greater than >3m (>10ft). In each graph, the area of any colour is proportional to how often that size swell occurs. The diagram indicates that the prevailing swell direction, shown by the biggest spokes, was SSW, whereas the the dominant wind blows from the NNW. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Petatlan and out to sea. We lump these in with the no surf category of the bar chart. To simplify things we don't show these in the rose plot. Because wind determines whether or not waves are clean enough to surf at Petatlan, you can view an alternative image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. Over an average August, swells large enough to cause surfable waves at Petatlan run for about 99% of the time.

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