Barra do Sai Surf Stats

This chart illustrates the combination of swells directed at Barra do Sai over a normal July. It is based on 3720 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coast so we have chosen the best grid node based on what we know about Barra do Sai. In this particular case the best grid node is 25 km away (16 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 58% of the time. Green and yellow represent increasing swell sizes and largest swells greater than >3m (>10ft) are shown in red. In both graphs, the area of any colour is proportional to how frequently that size swell happens. The diagram suggests that the prevailing swell direction, shown by the biggest spokes, was SSE, whereas the the most common 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 Barra do Sai and out to sea. We group 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 Barra do Sai, you can load a different image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. During a typical July, swells large enough to cause clean enough to surf waves at Barra do Sai run for about 42% of the time.

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