Portballintrae Surf Stats

The graph shows the variation of swells directed at Portballintrae through a typical October, based on 3471 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the coastline so we have chosen the most applicable grid node based on what we know about Portballintrae. In this particular case the best grid node is 31 km away (19 miles). The rose diagram shows the distribution of swell sizes and directions, while the graph at the bottom shows the same thing but lacks direction information. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These happened only 24% of the time. Green and yellow illustrate increasing swell sizes and red represents biggest swells greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how commonly that size swell happens. The diagram implies that the prevailing swell direction, shown by the biggest spokes, was WNW, whereas the the prevailing wind blows from the SSW. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Portballintrae and out to sea. We group these with the no surf category of the bar chart. To keep it simple we don't show these in the rose graph. Because wind determines whether or not waves are clean enough to surf at Portballintrae, 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 October, swells large enough to cause surfable waves at Portballintrae run for about 76% of the time.

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