Aberavon Swell Statistics, September: Surf with Light or Offshore Winds
This image shows only the swells directed at Aberavon that coincided with light winds or offshore conditions through a typical September. It is based on 2398 predictions, one every 3 hours. The direction of the spokes show where quality surf generating swell comes from. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. Green and yellow show increasing swell sizes and red illustrates highest swells greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how commonly that size swell was forecast.
The diagram implies that the most common swell direction, shown by the biggest spokes, was WSW (which was the same as the dominant wind direction). 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 8% of the time, equivalent to 2 days. Open sea swells exceeding >3m (>10ft) are unlikely to occur in a normal September. Taking into account the proportion of these swells that coincided with predicted offshore winds, and given the fact that Aberavon is exposed to open water swells, we estimate that clean surf can be found at Aberavon about 8% of the time and that surf is messed up by onshore wind 52% of the time. This is means that we expect 18 days with waves in a typical September, of which 2 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.