35th Street Iop Swell Statistics, September: All Swell – Any Wind
The figure shows the combination of swells directed at 35th Street Iop through an average September and is based upon 2160 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the coastline so we have chosen the best grid node based on what we know about 35th Street Iop, and at 35th Street Iop the best grid node is 39 km away (24 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 were forecast 20% of the time. Green and yellow illustrate increasing swell sizes and red shows biggest 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 most common swell direction, shown by the biggest spokes, was ESE, whereas the the prevailing wind blows from the E. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from 35th Street Iop and offshore. We group 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 surfable at 35th Street Iop, you can select a similar diagram that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. In a typical September, swells large enough to cause good for surfing waves at 35th Street Iop run for about 80% 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.