Bruny Island - Mabel Bay Surf Stats

The graph describes the range of swells directed at Bruny Island - Mabel Bay through an average July. It is based on 3472 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 most applicable grid node based on what we know about Bruny Island - Mabel Bay, and at Bruny Island - Mabel Bay the best grid node is 13 km away (8 miles). The rose diagram describes the distribution of swell sizes and directions, 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 9% of the time. Green and yellow illustrate increasing swell sizes and highest swells greater than >3m (>10ft) are shown in red. In each graph, the area of any colour is proportional to how commonly that size swell happens. The diagram implies that the prevailing swell direction, shown by the largest spokes, was SSW, whereas the the dominant wind blows from the WNW. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Bruny Island - Mabel Bay and offshore. We combine these with the no surf category of the bar chart. To simplify things we don't show these in the rose diagram. Because wind determines whether or not waves are clean enough to surf at Bruny Island - Mabel Bay, 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 July, swells large enough to cause surfable waves at Bruny Island - Mabel Bay run for about 91% of the time.

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