Trá Na Rosan Surf Stats

This picture describes the variation of swells directed at Trá Na Rosan through a typical July. It is based on 3472 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the coast so we have chosen the optimum grid node based on what we know about Trá Na Rosan. In this particular case the best grid node is 32 km away (20 miles). The rose diagram describes the distribution of swell sizes and directions, while the graph at the bottom shows the same thing but without direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These occurred only 82% of the time. Green and yellow illustrate increasing swell sizes and highest swells greater than >3m (>10ft) are shown in red. 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 longest spokes, was NW, whereas the the dominant wind blows from the WSW. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Trá Na Rosan and away from the coast. We group these 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 surfable at Trá Na Rosan, you can select a similar diagram that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. Over an average July, swells large enough to cause good for surfing waves at Trá Na Rosan run for about 11% of the time.

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