Afife Swell Statistics, Autumn: All Swell – Any Wind
The rose diagram shows the variation of swells directed at Afife through an average northern hemisphere autumn, based on 6516 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the shore so we have chosen the optimum grid node based on what we know about Afife, and at Afife the best grid node is 27 km away (17 miles).
The rose diagram illustrates the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing 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 6% of the time. Green and yellow illustrate increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In both graphs, 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 biggest spokes, was WNW, whereas the the prevailing wind blows from the N. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Afife and away from the coast. We combine these 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 Afife, 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 northern hemisphere autumn, swells large enough to cause surfable waves at Afife run for about 94% 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.