Aticama Swell Statistics, Aprile: All Swell – Any Wind
This picture illustrates the combination of swells directed at Aticama over a normal April and is based upon 2160 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind and surf right at the coastline so we have chosen the best grid node based on what we know about Aticama. In this particular case the best grid node is 31 km away (19 miles).
The rose diagram shows the distribution of swell sizes and directions, while the graph at the bottom shows the same thing but lacks direction information. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These were forecast 9% of the time. Green and yellow show increasing swell sizes and red shows the largest swells, greater than >3m (>10ft). In each graph, the area of any colour is proportional to how frequently that size swell happens.
The diagram suggests that the prevailing swell direction, shown by the biggest spokes, was SSW, whereas the the most common wind blows from the NNW. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Aticama 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 Aticama, you can load a different image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. During a typical April, swells large enough to cause clean enough to surf waves at Aticama run for about 91% 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.