Anse Couleuvre Swell Statistics, September: All Swell – Any Wind
The rose diagram describes the variation of swells directed at Anse Couleuvre through an average September, based on 2400 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the coast so we have chosen the most applicable grid node based on what we know about Anse Couleuvre. In the case of Anse Couleuvre, the best grid node is 28 km away (17 miles).
The rose diagram shows the distribution of swell sizes and directions, 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 81% of the time. Green and yellow show increasing swell sizes and red illustrates the highest swells, greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how frequently that size swell happens.
The diagram suggests that the most common swell direction, shown by the largest spokes, was NE, whereas the the dominant 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 Anse Couleuvre and out to sea. We lump these in with the no surf category of the bar chart. To avoid confusion we don't show these in the rose diagram. Because wind determines whether or not waves are good for surfing at Anse Couleuvre, you can load a different image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. In a typical September, swells large enough to cause clean enough to surf waves at Anse Couleuvre run for about 11% 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.