Thunder Surf Stats

The rose diagram describes the variation of swells directed at Thunder over a normal June. It is based on 3384 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 Thunder. In this particular case the best grid node is 14 km away (9 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 show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These were forecast only 0% of the time. Green and yellow illustrate increasing swell sizes and red represents highest swells greater than >3m (>10ft). In each graph, 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 longest spokes, was E (which was the same as the dominant wind direction). Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Thunder 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 plot. Because wind determines whether or not waves are clean enough to surf at Thunder, you can view an alternative image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. During a typical June, swells large enough to cause surfable waves at Thunder run for about 27% of the time.

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