I and Js Surf Stats

This picture shows the variation of swells directed at I and Js over a normal September and is based upon 3360 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 I and Js. In the case of I and Js, the best grid node is 35 km away (22 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 show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These happened only 13% of the time. Green and yellow show increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In either graph, the area of any colour is proportional to how often that size swell occurs. The diagram indicates that the dominant swell direction, shown by the largest spokes, was WSW, whereas the the prevailing wind blows from the SW. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from I and Js and away from the coast. We combine these with the no surf category of the bar chart. To keep it simple we don't show these in the rose diagram. Because wind determines whether or not waves are clean enough to surf at I and Js, you can view an alternative image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. During a typical September, swells large enough to cause surfable waves at I and Js run for about 87% of the time.

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