Aan Swell Statistics, Spring: All Swell – Any Wind
The graph describes the range of swells directed at Aan over a normal southern hemisphere spring and is based upon 7252 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coastline so we have chosen the optimum grid node based on what we know about Aan, and at Aan the best grid node is 23 km away (14 miles).
The rose diagram describes 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 happened only 0.4% of the time. Green and yellow show increasing swell sizes and red shows the highest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how frequently that size swell was forecast.
The diagram suggests that the dominant swell direction, shown by the largest spokes, was SW, whereas the the dominant wind blows from the S. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Aan and away from the coast. We combine these with the no surf category of the bar chart. To avoid confusion we don't show these in the rose plot. Because wind determines whether or not waves are surfable at Aan, you can view an alternative image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. During a typical southern hemisphere spring, swells large enough to cause good for surfing waves at Aan run for about 92% 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.