Three Arch Bay Surf Stats

The figure shows the variation of swells directed at Three Arch Bay over a normal July. It is based on 3472 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coast so we have chosen the best grid node based on what we know about Three Arch Bay. In the case of Three Arch Bay, the best grid node is 21 km away (13 miles). The rose diagram describes the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but lacks 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 occurred only 3% of the time. Green and yellow show increasing swell sizes and red represents biggest swells greater than >3m (>10ft). In each graph, the area of any colour is proportional to how commonly that size swell occurs. The diagram implies that the most common swell direction, shown by the biggest spokes, was SSW, whereas the the prevailing wind blows from the WSW. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Three Arch Bay and away from the coast. We combine these with the no surf category of the bar chart. To simplify things we don't show these in the rose diagram. Because wind determines whether or not waves are surfable at Three Arch Bay, you can load a different image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. During a typical July, swells large enough to cause good for surfing waves at Three Arch Bay run for about 97% of the time.

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