Bambra Reef Swell Statistics, Summer: All Swell – Any Wind
The rose diagram illustrates the range of swells directed at Bambra Reef through an average southern hemisphere summer and is based upon 6365 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the coast so we have chosen the optimum grid node based on what we know about Bambra Reef. In the case of Bambra Reef, the best grid node is 67 km away (42 miles).
The rose diagram describes the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing 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 31% of the time. Green and yellow show increasing swell sizes and largest swells greater than >3m (>10ft) are shown in red. In either graph, the area of any colour is proportional to how often that size swell happens.
The diagram indicates that the dominant swell direction, shown by the biggest spokes, was SSW, whereas the the most common wind blows from the WNW. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Bambra Reef and offshore. We combine these with the no surf category of the bar chart. To avoid confusion we don't show these in the rose graph. Because wind determines whether or not waves are surfable at Bambra Reef, 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 southern hemisphere summer, swells large enough to cause good for surfing waves at Bambra Reef 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.