Noosa - Alexandria Bay Swell Statistics, Autumn: All Swell – Any Wind
This image illustrates the variation of swells directed at Noosa - Alexandria Bay through an average southern hemisphere autumn, based on 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 Noosa - Alexandria Bay. In the case of Noosa - Alexandria Bay, the best grid node is 40 km away (25 miles).
The rose diagram describes the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but without direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These happened only 73% of the time. Green and yellow illustrate increasing swell sizes and red illustrates the largest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how frequently that size swell was forecast.
The diagram suggests that the dominant swell direction, shown by the largest spokes, was SSE, whereas the the most common wind blows from the SE. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Noosa - Alexandria Bay 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 diagram. Because wind determines whether or not waves are good for surfing at Noosa - Alexandria Bay, you can select a similar diagram that shows only the swells that were expected to coincide with glassy or offshore wind conditions. In a typical southern hemisphere autumn, swells large enough to cause clean enough to surf waves at Noosa - Alexandria Bay 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.