Ballyhiernan Bay Surf Stats

The figure describes the range of swells directed at Ballyhiernan Bay over a normal June, based on 3506 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coastline so we have chosen the most applicable grid node based on what we know about Ballyhiernan Bay. In the case of Ballyhiernan Bay, the best grid node is 33 km away (21 miles). The rose diagram shows the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but lacks direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These happened only 62% of the time. Green and yellow illustrate increasing swell sizes and highest swells greater than >3m (>10ft) are shown in red. In either graph, the area of any colour is proportional to how frequently that size swell was forecast. The diagram suggests that the dominant swell direction, shown by the longest spokes, was NW, whereas the the dominant wind blows from the WNW. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Ballyhiernan Bay and out to sea. We lump these in with the no surf category of the bar chart. To keep it simple we don't show these in the rose diagram. Because wind determines whether or not waves are clean enough to surf at Ballyhiernan Bay, you can select a similar diagram that shows only the swells that were expected to coincide with glassy or offshore wind conditions. During a typical June, swells large enough to cause surfable waves at Ballyhiernan Bay run for about 38% of the time.

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