Agnes Waters Swell Statistics, April: 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 April. It is based on 2160 predictions, one every 3 hours. The direction of the spokes show where quality surf generating swell comes from. Five colours represent increasing wave sizes. Very small swells of less than 0.5m (1.5 feet) high are shown in blue. Green and yellow show increasing swell sizes and red shows the biggest 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 largest spokes, was E, whereas the the prevailing wind blows from the SE. 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 11% of the time, equivalent to 3 days. Open sea swells exceeding >3m (>10ft) are unlikely to happen in a normal April. Taking into account the ratio of these swells that coincided with expected offshore winds, and given the fact that Agnes Waters is exposed to open water swells, we estimate that clean surf can be found at Agnes Waters about 11% of the time and that surf is spoilt by onshore wind 53% of the time. This is means that we expect 19 days with waves in a typical April, of which 3 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.