Annascaul Rivermouth Swell Statistics, December: 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 December and is based upon 2457 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 illustrate increasing swell sizes and red shows highest swells greater than >3m (>10ft). In either graph, the area of any colour is proportional to how often that size swell occurs.
The diagram indicates that the prevailing swell direction, shown by the longest spokes, was WSW, whereas the the dominant 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 2% of the time, equivalent to 1 days. Open sea swells exceeding >3m (>10ft) are unlikely to happen in a normal December. Taking into account the proportion of these swells that coincided with forecast 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 2% of the time and that surf is spoilt by onshore wind 56% of the time. This is means that we expect 17 days with waves in a typical December, of which 1 days should be surfable.
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.