Agate and Pearl Street Swell Statistics, August: Surf with Light or Offshore Winds
The rose diagram shows only the swells directed at Agate and Pearl Street that coincided with light winds or offshore conditions through a typical August. It is based on 2480 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 show increasing swell sizes and red illustrates highest swells greater than >3m (>10ft). In both graphs, 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 biggest spokes, was WSW (which was the same as the dominant 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 4% of the time, equivalent to 1 days. Open sea swells exceeding >3m (>10ft) are unlikely to happen in a normal August. Taking into account the fraction of these swells that coincided with expected offshore winds, and given the fact that Agate and Pearl Street is exposed to open water swells, we calculate that clean surf can be found at Agate and Pearl Street about 4% of the time and that surf is messed up by onshore wind 4% of the time. This is means that we expect 2 days with waves in a typical August, of which 1 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.