Statistiques de Houle pour Anse de Cabestan, Juin: Toutes Houles – Tous Vents
The figure illustrates the variation of swells directed at Anse de Cabestan through an average June, based on 2306 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 Anse de Cabestan, and at Anse de Cabestan the best grid node is 11 km away (7 miles).
The rose diagram illustrates the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing but without direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These happened only 20% of the time. Green and yellow illustrate increasing swell sizes and red represents largest swells greater than >3m (>10ft). In each graph, 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 WSW, whereas the the most common wind blows from the WNW. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Anse de Cabestan and offshore. We lump these in with the no surf category of the bar chart. To keep it simple we don't show these in the rose diagram. Because wind determines whether or not waves are clean enough to surf at Anse de Cabestan, you can load a different image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. In a typical June, swells large enough to cause surfable waves at Anse de Cabestan run for about 80% of the time.
IMPORTANT: Beta version feature! Swell heights are open water values from NWW3. There is no attempt to model near-shore effects. Coastal wave heights will generally be less, especially if the break does not have unobstructed exposure to the open ocean.