Acid Drops Swell Statistics, September: All Swell – Any Wind
The graph illustrates the combination of swells directed at Acid Drops through a typical September. It is based on 2400 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 Acid Drops, and at Acid Drops the best grid node is 42 km away (26 miles).
The rose diagram shows the distribution of swell sizes and directions, 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 happened only 62% of the time. Green and yellow illustrate increasing swell sizes and red represents the largest 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 prevailing swell direction, shown by the biggest spokes, was S, whereas the the most common wind blows from the ENE. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Acid Drops and away from the coast. We group these 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 surfable at Acid Drops, you can view an alternative image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. Over an average September, swells large enough to cause good for surfing waves at Acid Drops run for about 38% 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.