Statistiques de Houle pour Agnes Waters, Janvier: Vagues avec Vents Légers ou Favorables.
This image shows only the swells directed at Agnes Waters that coincided with light winds or offshore conditions over a normal January. It is based on 2372 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 illustrate increasing swell sizes and red illustrates largest swells greater than >3m (>10ft). In either graph, the area of any colour is proportional to how commonly that size swell was forecast.
The diagram implies that the prevailing swell direction, shown by the largest spokes, was E, 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 4% of the time, equivalent to 1 days. Open sea swells exceeding >3m (>10ft) are unlikely to occur in a normal January. Taking into account the fraction of these swells that coincided with expected offshore winds, and given the fact that Agnes Waters is exposed to open water swells, we estimate that clean surf can be found at Agnes Waters about 4% of the time and that surf is messed up by onshore wind 73% of the time. This is means that we expect 24 days with waves in a typical January, 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.