Prainha Surf Stats

The graph describes the variation of swells directed at Prainha over a normal April, based on 3360 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind and surf right at the coastline so we have chosen the most applicable grid node based on what we know about Prainha. In the case of Prainha, the best grid node is 26 km away (16 miles). The rose diagram shows the distribution of swell sizes and directions, while the graph at the bottom shows the same thing but without direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These occurred 73% of the time. Green and yellow show increasing swell sizes and red illustrates the highest swells, greater than >3m (>10ft). In each graph, the area of any colour is proportional to how commonly that size swell was forecast. The diagram implies that the most common swell direction, shown by the largest spokes, was SSE, 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 Prainha and away from the coast. We lump these in with the no surf category of the bar chart. To simplify things we don't show these in the rose diagram. Because wind determines whether or not waves are clean enough to surf at Prainha, you can view an alternative image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. During a typical April, swells large enough to cause surfable waves at Prainha run for about 27% of the time.

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