Airport Lefts Swell Statistics, October: All Swell – Any Wind
The figure illustrates the variation of swells directed at Airport Lefts over a normal October and is based upon 2480 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 optimum grid node based on what we know about Airport Lefts. In this particular case the best grid node is 33 km away (21 miles).
The rose diagram shows 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 0% of the time. Green and yellow show increasing swell sizes and largest swells greater than >3m (>10ft) are shown in red. In each graph, the area of any colour is proportional to how frequently that size swell occurs.
The diagram suggests that the prevailing swell direction, shown by the largest spokes, was SSW, whereas the the most common wind blows from the SE. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Airport Lefts and out to sea. We lump these in with the no surf category of the bar chart. To simplify things we don't show these in the rose plot. Because wind determines whether or not waves are clean enough to surf at Airport Lefts, you can select a similar diagram that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. During a typical October, swells large enough to cause surfable waves at Airport Lefts run for about 100% 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.