Barra do Sai Surf Stats

The graph shows the variation 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 or surf right at the coast so we have chosen the most applicable grid node based on what we know about Barra do Sai, and at Barra do Sai the best grid node is 15 km away (9 miles). The rose diagram illustrates the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but lacks 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 69% of the time. Green and yellow represent increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In each graph, the area of any colour is proportional to how frequently that size swell was forecast. The diagram suggests that the prevailing swell direction, shown by the largest spokes, was SSE, whereas the the prevailing wind blows from the E. 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 lump these in with the no surf category of the bar chart. To simplify things we don't show these in the rose plot. Because wind determines whether or not waves are clean enough to surf at Barra do Sai, you can select a similar diagram 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 surfable waves at Barra do Sai run for about 31% of the time.

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