A Street Swell Statistics, November: All Swell – Any Wind
This picture shows the variation of swells directed at A Street through an average November. It is based on 2387 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the coast so we have chosen the optimum grid node based on what we know about A Street. In this particular case the best grid node is 33 km away (21 miles).
The rose diagram shows the distribution of swell sizes and directions, 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 86% of the time. Green and yellow represent increasing swell sizes and red represents the biggest swells, greater than >3m (>10ft). In each graph, the area of any colour is proportional to how frequently that size swell was forecast.
The diagram suggests that the prevailing swell direction, shown by the largest spokes, was ESE, whereas the the prevailing wind blows from the NNE. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from A Street 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 graph. Because wind determines whether or not waves are surfable at A Street, you can load a different image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. In a typical November, swells large enough to cause good for surfing waves at A Street run for about 4% 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.