Kahuku Ranch Surf Stats

The graph shows the variation of swells directed at Kahuku Ranch over a normal October. It is based on 3471 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 most applicable grid node based on what we know about Kahuku Ranch, and at Kahuku Ranch 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 without direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These occurred only 82% 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 often that size swell was forecast. The diagram indicates that the most common swell direction, shown by the biggest spokes, was SSW, whereas the the prevailing wind blows from the E. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Kahuku Ranch and out to sea. We group these with the no surf category of the bar chart. To simplify things we don't show these in the rose graph. Because wind determines whether or not waves are good for surfing at Kahuku Ranch, 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 October, swells large enough to cause clean enough to surf waves at Kahuku Ranch run for about 18% of the time.

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