Woonona Swell Statistics, Winter: All Swell – Any Wind
This image illustrates the combination of swells directed at Woonona over a normal southern hemisphere winter, based on 5802 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coastline so we have chosen the best grid node based on what we know about Woonona. In this particular case the best grid node is 11 km away (7 miles).
The rose diagram illustrates the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing but without 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 occurred only 73% of the time. Green and yellow show increasing swell sizes and red illustrates the largest swells, greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how often that size swell occurs.
The diagram indicates that the most common swell direction, shown by the biggest spokes, was ENE, whereas the the most common wind blows from the W. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Woonona 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 clean enough to surf at Woonona, you can load a different image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. During a typical southern hemisphere winter, swells large enough to cause surfable waves at Woonona run for about 27% 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.