Praia de Altura Surf Stats

The figure shows the combination of swells directed at Praia de Altura through an average July, 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 optimum grid node based on what we know about Praia de Altura. In the case of Praia de Altura, the best grid node is 19 km away (12 miles). The rose diagram shows the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing but lacks 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 89% of the time. Green and yellow illustrate increasing swell sizes and red illustrates the biggest swells, greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how often that size swell was forecast. The diagram indicates that the prevailing swell direction, shown by the biggest spokes, was SE, whereas the the prevailing wind blows from the WNW. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Praia de Altura and offshore. 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 clean enough to surf at Praia de Altura, you can select a similar diagram that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. In a typical July, swells large enough to cause surfable waves at Praia de Altura run for about 11% of the time.

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