Periwinkles Surf Stats

This picture shows the variation of swells directed at Periwinkles through a typical November. It is based on 3107 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the coastline so we have chosen the most applicable grid node based on what we know about Periwinkles, and at Periwinkles the best grid node is 37 km away (23 miles). The rose diagram shows the distribution of swell directions and swell sizes, 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 63% of the time. Green and yellow show increasing swell sizes and red represents the biggest swells, greater than >3m (>10ft). In each graph, the area of any colour is proportional to how commonly that size swell was forecast. The diagram implies that the prevailing swell direction, shown by the biggest spokes, was ESE, whereas the the prevailing wind blows from the SE. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Periwinkles and offshore. We combine 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 clean enough to surf at Periwinkles, you can view an alternative image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. Over an average November, swells large enough to cause surfable waves at Periwinkles run for about 37% of the time.

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