Armadale Bay Swell Statistics, Aprile: Surf with Light or Offshore Winds
This image shows only the swells directed at Armadale Bay that coincided with light winds or offshore conditions through a typical April. It is based on 2160 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 illustrate increasing swell sizes and red illustrates the highest swells, greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how commonly that size swell occurs.
The diagram implies that the prevailing swell direction, shown by the biggest spokes, was WNW, whereas the the dominant wind blows from the SSW. 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 39% of the time, equivalent to 12 days. Open water swells exceeding >3m (>10ft) only happen 1.7% of the time in a typical April, equivalent to just one day but 15% of the time we expect swell in the range 2-3m (6.5-10ft) 15%, equivalent to (4 days). Taking into account the fraction of these swells that coincided with expected offshore winds, and given the fact that Armadale Bay is exposed to open water swells, we think that that clean surf can be found at Armadale Bay about 39% of the time and that surf is messed up by onshore wind 52% of the time. This is means that we expect 27 days with waves in a typical April, of which 12 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.