Aberarth Swell Statistics, February: All Swell – Any Wind
The rose diagram shows the combination of swells directed at Aberarth through a typical February and is based upon 2101 NWW3 model predictions since 2007 (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 Aberarth, and at Aberarth the best grid node is 32 km away (20 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 illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These occurred 36% of the time. Green and yellow illustrate increasing swell sizes and red shows biggest 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 prevailing swell direction, shown by the longest spokes, was SW (which was the same as the prevailing wind direction). Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Aberarth and out to sea. We group these 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 clean enough to surf at Aberarth, you can select a similar diagram that shows only the swells that were expected to coincide with glassy or offshore wind conditions. Over an average February, swells large enough to cause surfable waves at Aberarth run for about 34% 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.