The Dump Swell Statistics, November: All Swell – Any Wind
The rose diagram shows the combination of swells directed at The Dump through a typical November and is based upon 2147 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the shore so we have chosen the best grid node based on what we know about The Dump. In this particular case the best grid node is 28 km away (17 miles).
The rose diagram illustrates the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but without direction information. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These were forecast only 6% of the time. Green and yellow represent increasing swell sizes and red shows the biggest swells, greater than >3m (>10ft). 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 biggest spokes, was W, whereas the the prevailing wind blows from the SSE. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from The Dump and offshore. We lump these in with the no surf category of the bar chart. To keep it simple we don't show these in the rose plot. Because wind determines whether or not waves are clean enough to surf at The Dump, you can load a different image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. Over an average November, swells large enough to cause surfable waves at The Dump run for about 94% 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.