Statistiques de Surf de Ballydavid

The figure shows the variation of swells directed at Ballydavid through an average October. It is based on 3471 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the coast so we have chosen the optimum grid node based on what we know about Ballydavid, and at Ballydavid the best grid node is 23 km away (14 miles). The rose diagram illustrates the distribution of swell sizes and directions, while the graph at the bottom shows the same thing without direction information. Five colours represent increasing wave sizes. Very small swells of less than 0.5m (1.5 feet) high are shown in blue. These happened only 93% of the time. Green and yellow represent increasing swell sizes and red represents the biggest swells, greater than >3m (>10ft). In both graphs, 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 longest spokes, was NNW, whereas the the prevailing wind blows from the SW. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Ballydavid and out to sea. We lump these in with the no surf category of the bar chart. To simplify things we don't show these in the rose graph. Because wind determines whether or not waves are clean enough to surf at Ballydavid, you can select a similar diagram that shows only the swells that were expected to coincide with glassy or offshore wind conditions. In a typical October, swells large enough to cause surfable waves at Ballydavid run for about 3% of the time.

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