Atacames Swell Statistics, Spring: All Swell – Any Wind
The rose diagram describes the combination of swells directed at Atacames over a normal northern hemisphere spring and is based upon 6580 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind and surf right at the coast so we have chosen the most applicable grid node based on what we know about Atacames. In the case of Atacames, the best grid node is 23 km away (14 miles).
The rose diagram illustrates the distribution of swell sizes and directions, while the graph at the bottom shows the same thing but without 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 only 70% of the time. Green and yellow represent increasing swell sizes and red shows the highest swells, greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how commonly that size swell was forecast.
The diagram implies that the prevailing swell direction, shown by the biggest spokes, was WNW, whereas the the dominant wind blows from the SW. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Atacames and offshore. 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 good for surfing at Atacames, 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 northern hemisphere spring, swells large enough to cause clean enough to surf waves at Atacames run for about 30% 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.