Augusta Rivermouth Swell Statistics, April: Surf with Light or Offshore Winds
This image shows only the swells directed at Augusta Rivermouth that coincided with light winds or offshore conditions over a normal April and is based upon 2160 predictions, one every 3 hours. The direction of the spokes show where quality surf generating swell comes from. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. Green and yellow illustrate increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In either graph, the area of any colour is proportional to how commonly that size swell happens.
The diagram implies that the prevailing swell direction, shown by the biggest spokes, was SSW, whereas the the prevailing wind blows from the SSE. 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 10% of the time, equivalent to 3 days. Open water swells exceeding >3m (>10ft) only arise 3% of the time in a typical April, equivalent to just one day but 5% of the time we expect swell in the range 2-3m (6.5-10ft) 5%, equivalent to (2 days). Taking into account the fraction of these swells that coincided with expected offshore winds, and given the fact that Augusta Rivermouth is slightly protected from open water swells, we calculate that clean surf can be found at Augusta Rivermouth about 10% of the time and that surf is messed up by onshore wind 35% of the time. This is means that we expect 14 days with waves in a typical April, of which 3 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.