Ardmore Swell Statistics, Spring: Surf with Light or Offshore Winds
The rose diagram shows only the swells directed at Ardmore that coincided with light winds or offshore conditions through a typical northern hemisphere spring and is based upon 6580 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 represents the largest swells, greater than >3m (>10ft). In each graph, the area of any colour is proportional to how often that size swell occurs.
The diagram indicates that the most common swell direction, shown by the longest spokes, was SW, whereas the the most common wind blows from the WSW. 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 0.1% of the time, equivalent to 0 days. Open sea swells exceeding >3m (>10ft) are unlikely to happen in a normal northern hemisphere spring. Taking into account the fraction of these swells that coincided with expected offshore winds, and given the fact that Ardmore is quite sheltered from open water swells, we estimate that clean surf can be found at Ardmore about 0.1% of the time and that surf is spoilt by onshore wind 5% of the time. This is means that we expect 5 days with waves in a typical northern hemisphere spring, of which 0 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.