Ponta Negra Surf Stats

The figure describes the combination of swells directed at Ponta Negra through a typical April. It is based on 3360 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast surf and wind right at the coastline so we have chosen the best grid node based on what we know about Ponta Negra. In this particular case the best grid node is 21 km away (13 miles). The rose diagram illustrates the distribution of swell directions and swell sizes, 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 occurred only 8% of the time. Green and yellow represent increasing swell sizes and red shows highest swells greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how often that size swell occurs. The diagram indicates that the most common swell direction, shown by the largest spokes, was NE, whereas the the dominant wind blows from the SE. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Ponta Negra and away from the coast. We combine these with the no surf category of the bar chart. To avoid confusion we don't show these in the rose plot. Because wind determines whether or not waves are good for surfing at Ponta Negra, you can select a similar diagram that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. Over an average April, swells large enough to cause clean enough to surf waves at Ponta Negra run for about 92% of the time.

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