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 through a typical April. It is based on 1920 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 red illustrates biggest swells greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how often that size swell happens.
The diagram indicates that the dominant swell direction, shown by the largest spokes, was SW, whereas the the prevailing wind blows from the S. 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 6% of the time, equivalent to 2 days. Open sea swells exceeding >3m (>10ft) are unlikely to arise in a normal April. Taking into account the ratio of these swells that coincided with expected offshore winds, and given the fact that Centinela is exposed to open water swells, we estimate that clean surf can be found at Centinela about 6% of the time and that surf is blown out by onshore wind 94% of the time. This is means that we expect 30 days with waves in a typical April, of which 2 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.