Annascaul Rivermouth Swell Statistics, Autumn: Surf with Light or Offshore Winds
This image shows only the swells directed at Annascaul Rivermouth 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 show increasing swell sizes and largest swells greater than >3m (>10ft) are shown in red. In each graph, the area of any colour is proportional to how often that size swell was forecast.
The diagram indicates that the most common swell direction, shown by the biggest spokes, was WSW, whereas the the most common 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 4% of the time, equivalent to 4 days. Open water swells exceeding >3m (>10ft) only occur 0.7% of the time in a typical northern hemisphere autumn, equivalent to just one day but 3% of the time we expect swell in the range 2-3m (6.5-10ft) 3%, equivalent to (3 days). Taking into account the ratio of these swells that coincided with predicted offshore winds, and given the fact that Annascaul Rivermouth is quite sheltered from open water swells, we estimate that clean surf can be found at Annascaul Rivermouth about 4% of the time and that surf is spoilt by onshore wind 43% of the time. This is means that we expect 43 days with waves in a typical northern hemisphere autumn, of which 4 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.