This image shows only the swells directed at Grand Mere that coincided with light winds or offshore conditions over a normal July. It is based on 1736 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 show increasing swell sizes and largest swells greater than >3m (>10ft) are shown in red. In each graph, 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 N, whereas the the most common wind blows from the E. 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 0% of the time, equivalent to 0 days. Open sea swells exceeding >3m (>10ft) are unlikely to happen in a normal July. Taking into account the proportion of these swells that coincided with forecast offshore winds we think that that clean surf can be found at Grand Mere about 0% of the time and that surf is messed up by onshore wind 3% of the time. This is means that we expect 1 days with waves in a typical July, of which 0 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.