Andromeda Swell Statistics, Autumn: All Swell – Any Wind
The graph shows the combination of swells directed at Andromeda through a typical southern hemisphere autumn and is based upon 6580 NWW3 model predictions since 2007 (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 Andromeda, and at Andromeda the best grid node is 63 km away (39 miles).
The rose diagram illustrates 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 1.5% of the time. Green and yellow show increasing swell sizes and red shows biggest swells greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how often that size swell was forecast.
The diagram indicates that the most common swell direction, shown by the largest spokes, was SW, whereas the the prevailing wind blows from the SSW. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Andromeda and offshore. We group these with the no surf category of the bar chart. To keep it simple we don't show these in the rose graph. Because wind determines whether or not waves are surfable at Andromeda, you can load a different 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 good for surfing waves at Andromeda run for about 98% 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.