K38 and 39 Surf Stats

The graph describes the variation of swells directed at K38 and 39 through an average September. It is based on 3360 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the shore so we have chosen the most applicable grid node based on what we know about K38 and 39, and at K38 and 39 the best grid node is 41 km away (25 miles). The rose diagram describes the distribution of swell sizes and directions, 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 were forecast only 13% of the time. Green and yellow show increasing swell sizes and red represents the highest 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 prevailing swell direction, shown by the longest spokes, was SSE, whereas the the dominant wind blows from the NNE. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from K38 and 39 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 clean enough to surf at K38 and 39, you can view an alternative image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. In a typical September, swells large enough to cause surfable waves at K38 and 39 run for about 34% of the time.

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