Statistiques de Surf de Prainha

The graph shows the combination of swells directed at Prainha through a typical October, based on 3471 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coastline 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 shows the distribution of swell directions and swell sizes, 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 occurred only 14% of the time. Green and yellow illustrate increasing swell sizes and red illustrates the biggest swells, greater than >3m (>10ft). In each graph, the area of any colour is proportional to how often that size swell was forecast. The diagram indicates that the dominant swell direction, shown by the longest spokes, was SE, whereas the the prevailing wind blows from the ENE. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Prainha and out to sea. 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. Over an average October, swells large enough to cause clean enough to surf waves at Prainha run for about 62% of the time.

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