Andromeda Swell Statistics, Winter: All Swell – Any Wind
This image describes the variation of swells directed at Andromeda through an average southern hemisphere winter and is based upon 7266 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the shore so we have chosen the best grid node based on what we know about Andromeda. In the case of Andromeda, the best grid node is 63 km away (39 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 show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These happened only 0% of the time. Green and yellow illustrate increasing swell sizes and red represents highest swells greater than >3m (>10ft). In either graph, the area of any colour is proportional to how frequently that size swell occurs.
The diagram suggests that the prevailing swell direction, shown by the biggest spokes, was SW, whereas the the dominant wind blows from the SSW. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Andromeda and out to sea. We lump these in 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 Andromeda, you can select a similar diagram that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. In a typical southern hemisphere winter, swells large enough to cause surfable waves at Andromeda run for about 100% 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.