Centinela Swell Statistics, April: Surf with Light or Offshore Winds
This image shows only the swells directed at Centinela that coincided with light winds or offshore conditions over a normal 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 highest swells greater than >3m (>10ft). In either graph, the area of any colour is proportional to how commonly that size swell was forecast.
The diagram implies that the prevailing swell direction, shown by the biggest spokes, was SW, whereas the the dominant 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 4% of the time, equivalent to 1 days. Open sea swells exceeding >3m (>10ft) are unlikely to occur in a normal April. Taking into account the ratio of these swells that coincided with forecast offshore winds, and given the fact that Centinela is exposed to open water swells, we think that that clean surf can be found at Centinela about 4% of the time and that surf is spoilt by onshore wind 96% of the time. This is means that we expect 30 days with waves in a typical April, of which 1 days should be clean enough to surf.
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.