This image shows only the swells directed at Tarpits that coincided with light winds or offshore conditions over a normal September. It is based on 1680 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 illustrate increasing swell sizes and red represents biggest swells greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how commonly that size swell happens.
The diagram implies that the most common swell direction, shown by the biggest spokes, was SW, whereas the the prevailing wind blows from the W. 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 2.0% of the time, equivalent to 1 days. Open sea swells exceeding >3m (>10ft) are unlikely to arise in a normal September. Taking into account the fraction of these swells that coincided with forecast offshore winds, and given the fact that Tarpits is slightly protected from open water swells, we calculate that clean surf can be found at Tarpits about 2.0% of the time and that surf is blown out by onshore wind 10% of the time. This is means that we expect 4 days with waves in a typical September, 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.