Sandbox Swell Statistics, November: All Swell – Any Wind
This chart illustrates the combination of swells directed at Sandbox over a normal November. It is based on 2147 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the shore so we have chosen the best grid node based on what we know about Sandbox, and at Sandbox the best grid node is 19 km away (12 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 illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These were forecast only 63% of the time. Green and yellow represent increasing swell sizes and red represents the largest swells, greater than >3m (>10ft). In each graph, the area of any colour is proportional to how frequently that size swell occurs.
The diagram suggests that the most common swell direction, shown by the largest spokes, was W, whereas the the most common wind blows from the NNW. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Sandbox and away from the coast. 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 Sandbox, you can view an alternative image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. During a typical November, swells large enough to cause clean enough to surf waves at Sandbox run for about 37% 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.