Statistiques de Surf de Barra do Sahy

This picture illustrates the combination of swells directed at Barra do Sahy through a typical September. It is based on 3360 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the shore so we have chosen the optimum grid node based on what we know about Barra do Sahy, and at Barra do Sahy the best grid node is 31 km away (19 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 show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These were forecast only 42% of the time. Green and yellow illustrate increasing swell sizes and red represents the largest swells, greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how commonly that size swell happens. The diagram implies that the prevailing swell direction, shown by the longest spokes, was SSE, whereas the the most common wind blows from the E. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Barra do Sahy 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 graph. Because wind determines whether or not waves are good for surfing at Barra do Sahy, 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 September, swells large enough to cause clean enough to surf waves at Barra do Sahy run for about 58% of the time.

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