Annascaul Rivermouth Swell Statistics, Winter: 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 winter. It is based on 6931 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 red represents biggest swells greater than >3m (>10ft). In each graph, the area of any colour is proportional to how frequently that size swell was forecast.
The diagram suggests that the most common swell direction, shown by the longest spokes, was WSW (which was the same as the prevailing 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 5% of the time, equivalent to 5 days. Expect open water swells to exceed >3m (>10ft) 2% of the time (2 days). Taking into account the ratio of these swells that coincided with expected offshore winds, and given the fact that Annascaul Rivermouth is quite sheltered from open water swells, we calculate that clean surf can be found at Annascaul Rivermouth about 5% of the time and that surf is messed up by onshore wind 58% of the time. This is means that we expect 57 days with waves in a typical northern hemisphere winter, 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.