Quintana Jetty Swell Statistics, July: All Swell – Any Wind
This picture describes the variation of swells directed at Quintana Jetty through a typical July, based on 2480 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 optimum grid node based on what we know about Quintana Jetty, and at Quintana Jetty the best grid node is 19 km away (12 miles).
The rose diagram shows the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing but lacks direction information. Five colours represent increasing wave sizes. Very small swells of less than 0.5m (1.5 feet) high are shown in blue. These were forecast 54% of the time. Green and yellow show increasing swell sizes and red represents highest swells greater than >3m (>10ft). In either graph, the area of any colour is proportional to how often that size swell was forecast.
The diagram indicates that the prevailing swell direction, shown by the largest spokes, was SE, whereas the the dominant wind blows from the S. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Quintana Jetty and offshore. We lump these in 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 Quintana Jetty, you can view an alternative image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. Over an average July, swells large enough to cause good for surfing waves at Quintana Jetty run for about 46% 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.