Siouville Surf Stats

This image illustrates the variation of swells directed at Siouville over a normal April, based on 3357 NWW3 model predictions since 2007 (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 Siouville, and at Siouville the best grid node is 13 km away (8 miles). The rose diagram describes the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but without direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These were forecast 64% of the time. Green and yellow represent increasing swell sizes and largest swells greater than >3m (>10ft) are shown in red. In each graph, the area of any colour is proportional to how frequently that size swell occurs. The diagram suggests that the most common swell direction, shown by the largest spokes, was W, whereas the the most common wind blows from the NNE. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Siouville and offshore. We combine these with the no surf category of the bar chart. To keep it simple we don't show these in the rose diagram. Because wind determines whether or not waves are surfable at Siouville, 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 Siouville run for about 36% of the time.

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