Shipwrecks Bay-Peaks Swell Statistics, April: All Swell – Any Wind
This picture describes the variation of swells directed at Shipwrecks Bay-Peaks through a typical April, based on 2160 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind or surf right at the coast so we have chosen the best grid node based on what we know about Shipwrecks Bay-Peaks, and at Shipwrecks Bay-Peaks the best grid node is 23 km away (14 miles).
The rose diagram describes the distribution of swell sizes and directions, while the graph at the bottom shows the same thing without direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These were forecast only 1.8% of the time. Green and yellow show increasing swell sizes and red represents highest swells greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how commonly that size swell happens.
The diagram implies that the dominant swell direction, shown by the longest spokes, was SW, whereas the the dominant wind blows from the SE. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Shipwrecks Bay-Peaks and offshore. We lump these in 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 Shipwrecks Bay-Peaks, 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 April, swells large enough to cause good for surfing waves at Shipwrecks Bay-Peaks run for about 58% 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.