Ardmore Swell Statistics, May: All Swell – Any Wind
The figure illustrates the range of swells directed at Ardmore through a typical May. It is based on 2200 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind and surf right at the shore so we have chosen the optimum grid node based on what we know about Ardmore. In the case of Ardmore, the best grid node is 20 km away (12 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 illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These happened 51% of the time. Green and yellow illustrate increasing swell sizes and red represents the largest 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 longest spokes, was SW, whereas the the most common wind blows from the WSW. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Ardmore and out to sea. 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 Ardmore, you can load a different image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. Over an average May, swells large enough to cause clean enough to surf waves at Ardmore run for about 3% 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.