Prainha Surf Stats

The graph shows the combination of swells directed at Prainha through an average August, based on 3590 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 most applicable grid node based on what we know about Prainha. In this particular case the best grid node is 55 km away (34 miles). The rose diagram shows the distribution of swell sizes and swell direction, 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 17% of the time. Green and yellow illustrate increasing swell sizes and red shows biggest swells greater than >3m (>10ft). In each graph, the area of any colour is proportional to how frequently that size swell occurs. The diagram suggests that the most common swell direction, shown by the longest spokes, was SE, whereas the the prevailing wind blows from the NNE. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Prainha 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 graph. Because wind determines whether or not waves are good for surfing at Prainha, you can select a similar diagram that shows only the swells that were expected to coincide with glassy or offshore wind conditions. In a typical August, swells large enough to cause clean enough to surf waves at Prainha run for about 83% of the time.

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