Moonstone Surf Stats

The figure shows the variation of swells directed at Moonstone over a normal April. It is based on 2880 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind and surf right at the coastline so we have chosen the most applicable grid node based on what we know about Moonstone. In the case of Moonstone, the best grid node is 36 km away (22 miles). The rose diagram describes 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 occurred only 11% of the time. Green and yellow illustrate increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In both graphs, the area of any colour is proportional to how commonly that size swell happens. The diagram implies that the prevailing swell direction, shown by the biggest spokes, was WNW, whereas the the prevailing wind blows from the NW. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Moonstone and out to sea. We combine these with the no surf category of the bar chart. To keep it simple we don't show these in the rose graph. Because wind determines whether or not waves are clean enough to surf at Moonstone, you can load a different image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. During a typical April, swells large enough to cause surfable waves at Moonstone run for about 89% of the time.

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