Mouse Rock Swell Statistics, May: All Swell – Any Wind
The figure illustrates the variation of swells directed at Mouse Rock through an average May and is based upon 1910 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind or surf right at the coastline so we have chosen the optimum grid node based on what we know about Mouse Rock, and at Mouse Rock the best grid node is 50 km away (31 miles).
The rose diagram illustrates the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing without direction information. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These occurred only 20% of the time. Green and yellow illustrate increasing swell sizes and red represents largest swells greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how often that size swell happens.
The diagram indicates that the prevailing swell direction, shown by the biggest spokes, was WNW (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 Mouse Rock 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 surfable at Mouse Rock, you can view an alternative image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. In a typical May, swells large enough to cause good for surfing waves at Mouse Rock run for about 80% 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.