Aberwystwyth Beach Swell Statistics, Winter: All Swell – Any Wind
The figure illustrates the combination of swells directed at Aberwystwyth Beach through a typical northern hemisphere winter and is based upon 6930 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the coast so we have chosen the most applicable grid node based on what we know about Aberwystwyth Beach. In the case of Aberwystwyth Beach, the best grid node is 29 km away (18 miles).
The rose diagram illustrates the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but lacks direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These occurred 34% of the time. Green and yellow show increasing swell sizes and largest swells greater than >3m (>10ft) are shown in red. In both graphs, the area of any colour is proportional to how often that size swell was forecast.
The diagram indicates that the prevailing swell direction, shown by the longest spokes, was SW (which was the same as the most common wind direction). Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Aberwystwyth Beach 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 diagram. Because wind determines whether or not waves are surfable at Aberwystwyth Beach, you can select a similar diagram that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. Over an average northern hemisphere winter, swells large enough to cause good for surfing waves at Aberwystwyth Beach run for about 43% 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.