Army Beach Swell Statistics, Spring: Surf with Light or Offshore Winds
This image shows only the swells directed at Army Beach 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 represent increasing swell sizes and red illustrates largest swells greater than >3m (>10ft). In each graph, the area of any colour is proportional to how commonly that size swell was forecast.
The diagram implies that the prevailing swell direction, shown by the biggest spokes, was NW, whereas the the most common wind blows from the ENE. 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 12% of the time, equivalent to 11 days. Open sea swells exceeding >3m (>10ft) are unlikely to occur in a normal northern hemisphere spring 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 Army Beach is exposed to open water swells, we think that that clean surf can be found at Army Beach about 12% of the time and that surf is spoilt by onshore wind 42% of the time. This is means that we expect 49 days with waves in a typical northern hemisphere spring, of which 11 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.