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Rate Greenough River Mouth


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Greenough River Mouth Swell Statistics, Autumn: All Swell – Any Wind

The graph shows the range of swells directed at Greenough River Mouth through a typical southern hemisphere autumn and is based upon 8682 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind or surf right at the coast so we have chosen the most applicable grid node based on what we know about Greenough River Mouth. In this particular case the best grid node is 20 km away (12 miles).

The rose diagram describes the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing but lacks direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These happened only 0.3% of the time. Green and yellow show increasing swell sizes and red shows the biggest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how often that size swell occurs.

The diagram indicates that the dominant swell direction, shown by the biggest spokes, was SW, whereas the the prevailing wind blows from the SSE. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Greenough River Mouth and offshore. We lump these in with the no surf category of the bar chart. To avoid confusion we don't show these in the rose diagram. Because wind determines whether or not waves are clean enough to surf at Greenough River Mouth, you can view an alternative image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. Over an average southern hemisphere autumn, swells large enough to cause surfable waves at Greenough River Mouth run for about 88% 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.