Statistiques de Surf de Portao

The figure illustrates the variation of swells directed at Portao over a normal June. It is based on 3506 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the shore so we have chosen the best grid node based on what we know about Portao. In the case of Portao, the best grid node is 24 km away (15 miles). The rose diagram describes the distribution of swell sizes and directions, while the graph at the bottom shows the same thing but 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 happened only 53% of the time. Green and yellow represent increasing swell sizes and red represents largest swells greater than >3m (>10ft). In either graph, the area of any colour is proportional to how often that size swell occurs. The diagram indicates that the prevailing swell direction, shown by the longest spokes, was NE, whereas the the most common wind blows from the ESE. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Portao 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 good for surfing at Portao, you can select a similar diagram that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. During a typical June, swells large enough to cause clean enough to surf waves at Portao run for about 47% of the time.

read more