Grand-Lahou Surf Stats

The figure describes the combination of swells directed at Grand-Lahou over a normal September and is based upon 3360 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the coast so we have chosen the best grid node based on what we know about Grand-Lahou. In this particular case the best grid node is 24 km away (15 miles). The rose diagram illustrates the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but lacks 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 0% of the time. Green and yellow represent increasing swell sizes and highest swells greater than >3m (>10ft) are shown in red. In either graph, the area of any colour is proportional to how commonly that size swell occurs. The diagram implies that the dominant swell direction, shown by the biggest spokes, was S, whereas the the dominant wind blows from the SW. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Grand-Lahou 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 plot. Because wind determines whether or not waves are surfable at Grand-Lahou, you can select a similar diagram 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 good for surfing waves at Grand-Lahou run for about 100% of the time.

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