Statistiques de Surf de Three Arch Bay

The figure shows the variation of swells directed at Three Arch Bay through a typical June. It is based on 3384 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the shore so we have chosen the optimum grid node based on what we know about Three Arch Bay, and at Three Arch Bay the best grid node is 21 km away (13 miles). The rose diagram illustrates the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing without direction information. Five colours represent increasing wave sizes. Very small swells of less than 0.5m (1.5 feet) high are shown in blue. These were forecast only 3% of the time. Green and yellow represent increasing swell sizes and red represents biggest 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 dominant swell direction, shown by the longest spokes, was SSW, whereas the the prevailing wind blows from the SW. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Three Arch Bay 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 surfable at Three Arch Bay, you can select a similar diagram that shows only the swells that were expected to coincide with glassy or offshore wind conditions. Over an average June, swells large enough to cause good for surfing waves at Three Arch Bay run for about 97% of the time.

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