Prainha Surf Stats

This image illustrates the range of swells directed at Prainha through a typical November, based on 3347 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the shore so we have chosen the best grid node based on what we know about Prainha. In the case of Prainha, the best grid node is 18 km away (11 miles). The rose diagram describes the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing but lacks direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These were forecast only 14% of the time. Green and yellow illustrate increasing swell sizes and largest swells greater than >3m (>10ft) are shown in red. In either graph, the area of any colour is proportional to how frequently that size swell occurs. The diagram suggests that the dominant swell direction, shown by the largest spokes, was SE, whereas the the most common wind blows from the E. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Prainha and offshore. We combine these with the no surf category of the bar chart. To avoid confusion we don't show these in the rose graph. Because wind determines whether or not waves are surfable at Prainha, you can view an alternative image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. Over an average November, swells large enough to cause good for surfing waves at Prainha run for about 58% of the time.

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