Quintana Jetty Swell Statistics, July: All Swell – Any Wind
This chart describes the range of swells directed at Quintana Jetty through a typical July, based on 2342 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 Quintana Jetty. In the case of Quintana Jetty, the best grid node is 19 km away (12 miles).
The rose diagram illustrates the distribution of swell sizes and directions, 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 occurred 53% of the time. Green and yellow represent increasing swell sizes and red illustrates highest swells greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how frequently that size swell happens.
The diagram suggests that the prevailing swell direction, shown by the longest spokes, was SE, whereas the the dominant wind blows from the S. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Quintana Jetty and out to sea. We combine these 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 clean enough to surf at Quintana Jetty, you can load a different image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. Over an average July, swells large enough to cause surfable waves at Quintana Jetty run for about 47% 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.