Mompiche Swell Statistics, March: Surf with Light or Offshore Winds
This image shows only the swells directed at Mompiche that coincided with light winds or offshore conditions over a normal March. It is based on 1972 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 represent increasing swell sizes and highest swells greater than >3m (>10ft) are shown in red. In each graph, 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 SW. 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 15% of the time, equivalent to 5 days. Open sea swells exceeding >3m (>10ft) are unlikely to happen in a normal March. Taking into account the fraction of these swells that coincided with expected offshore winds, and given the fact that Mompiche is exposed to open water swells, we estimate that clean surf can be found at Mompiche about 15% of the time and that surf is spoilt by onshore wind 11% of the time. This is means that we expect 8 days with waves in a typical March, of which 5 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.