Anna Bay-Morna Point Swell Statistics, Autumn: Surf with Light or Offshore Winds
The rose diagram shows only the swells directed at Anna Bay-Morna Point that coincided with light winds or offshore conditions through a typical southern hemisphere autumn. It is based on 6580 predictions, one every 3 hours. The direction of the spokes show where quality surf generating swell comes from. Five colours represent increasing wave sizes. Very small swells of less than 0.5m (1.5 feet) high are shown in blue. Green and yellow show increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In each graph, the area of any colour is proportional to how frequently that size swell happens.
The diagram suggests that the prevailing swell direction, shown by the biggest spokes, was ESE, whereas the the prevailing wind blows from the SE. The chart at the bottom shows the same thing but without direction information. For example, swells larger than 1.5 feet (0.5m) coincided with good wind conditions 18% of the time, equivalent to 16 days. Open sea swells exceeding >3m (>10ft) are unlikely to arise in a normal southern hemisphere autumn but 4% of the time we expect swell in the range 2-3m (6.5-10ft) 4%, equivalent to (4 days). Taking into account the ratio of these swells that coincided with expected offshore winds, and given the fact that Anna Bay-Morna Point is slightly protected from open water swells, we think that that clean surf can be found at Anna Bay-Morna Point about 18% of the time and that surf is spoilt by onshore wind 31% of the time. This is means that we expect 45 days with waves in a typical southern hemisphere autumn, of which 16 days should be surfable.
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.