Assateague Swell Statistics, Gennaio: Surf with Light or Offshore Winds
This image shows only the swells directed at Assateague that coincided with light winds or offshore conditions over a normal January and is based upon 2372 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 represent increasing swell sizes and red represents highest 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 most common swell direction, shown by the largest spokes, was SE, whereas the the dominant wind blows from the WNW. 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 20% of the time, equivalent to 6 days. Open sea swells exceeding >3m (>10ft) are unlikely to happen in a normal January but 5% of the time you can expect swell in the range 1.3-2m (4-6.5ft) 5%, equivalent to (2 days). Taking into account the ratio of these swells that coincided with predicted offshore winds, and given the fact that Assateague is exposed to open water swells, we think that that clean surf can be found at Assateague about 20% of the time and that surf is messed up by onshore wind 20% of the time. This is means that we expect 12 days with waves in a typical January, of which 6 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.