Atlantic Terrace Swell Statistics, Autumn: Surf with Light or Offshore Winds
This image shows only the swells directed at Atlantic Terrace that coincided with light winds or offshore conditions through a typical northern hemisphere autumn and is based upon 7252 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 represent increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In either graph, the area of any colour is proportional to how often that size swell happens.
The diagram indicates that the prevailing swell direction, shown by the longest spokes, was SE, whereas the the prevailing wind blows from the WNW. 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 24% of the time, equivalent to 22 days. Open sea swells exceeding >3m (>10ft) are unlikely to arise in a normal northern hemisphere autumn but 4% of the time you can expect swell in the range 1.3-2m (4-6.5ft) 4%, equivalent to (4 days). Taking into account the fraction of these swells that coincided with forecast offshore winds, and given the fact that Atlantic Terrace is exposed to open water swells, we think that that clean surf can be found at Atlantic Terrace about 24% of the time and that surf is spoilt by onshore wind 36% of the time. This is means that we expect 55 days with waves in a typical northern hemisphere autumn, of which 22 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.