Nettley Bay Reefs Surf Stats

This picture shows the variation of swells directed at Nettley Bay Reefs over a normal February and is based upon 2664 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind or surf right at the coast so we have chosen the optimum grid node based on what we know about Nettley Bay Reefs. In this particular case the best grid node is 13 km away (8 miles). The rose diagram shows the distribution of swell sizes and directions, 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 were forecast only 3% of the time. Green and yellow illustrate increasing swell sizes and red shows the biggest swells, greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how frequently that size swell occurs. The diagram suggests that the prevailing swell direction, shown by the longest spokes, was SW, whereas the the prevailing wind blows from the SSE. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Nettley Bay Reefs and out to sea. We lump these in 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 good for surfing at Nettley Bay Reefs, 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 February, swells large enough to cause clean enough to surf waves at Nettley Bay Reefs run for about 97% of the time.

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