Agnes Waters Swell Statistics, September: Surf with Light or Offshore Winds
This image shows only the swells directed at Agnes Waters that coincided with light winds or offshore conditions over a normal September. It is based on 2400 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 represent increasing swell sizes and red illustrates largest swells greater than >3m (>10ft). In each graph, the area of any colour is proportional to how commonly that size swell occurs.
The diagram implies that the dominant swell direction, shown by the longest spokes, was ENE (which was the same as the most common 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 9% of the time, equivalent to 3 days. Open sea swells exceeding >3m (>10ft) are unlikely to happen in a normal September. Taking into account the fraction of these swells that coincided with expected offshore winds, and given the fact that Agnes Waters is exposed to open water swells, we think that that clean surf can be found at Agnes Waters about 9% of the time and that surf is messed up by onshore wind 57% of the time. This is means that we expect 20 days with waves in a typical September, of which 3 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.