Alibaba Swell Statistics, October: Surf with Light or Offshore Winds
This image shows only the swells directed at Alibaba that coincided with light winds or offshore conditions through a typical October and is based upon 2480 predictions, one every 3 hours. The direction of the spokes show where quality surf generating swell comes from. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. Green and yellow represent increasing swell sizes and red represents the largest swells, greater than >3m (>10ft). In either graph, the area of any colour is proportional to how often that size swell happens.
The diagram indicates that the dominant swell direction, shown by the biggest spokes, was NW, whereas the the most common wind blows from the NE. 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 4 days. Open sea swells exceeding >3m (>10ft) are unlikely to arise in a normal October but 9% of the time you can expect swell in the range 1.3-2m (4-6.5ft) 9%, equivalent to (3 days). Taking into account the fraction of these swells that coincided with forecast offshore winds, and given the fact that Alibaba is exposed to open water swells, we think that that clean surf can be found at Alibaba about 12% of the time and that surf is blown out by onshore wind 37% of the time. This is means that we expect 15 days with waves in a typical October, of which 4 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.