Balevullin (Tiree) Surf Stats

This picture describes the variation of swells directed at Balevullin (Tiree) over a normal April. It is based on 3360 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind or surf right at the coast so we have chosen the best grid node based on what we know about Balevullin (Tiree), and at Balevullin (Tiree) the best grid node is 4 km away (2 miles). The rose diagram shows the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing without direction information. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These were forecast only 24% of the time. Green and yellow illustrate increasing swell sizes and red represents highest 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 dominant swell direction, shown by the longest spokes, was WNW, whereas the the dominant wind blows from the SSW. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Balevullin (Tiree) and away from the coast. We lump these in with the no surf category of the bar chart. To avoid confusion we don't show these in the rose graph. Because wind determines whether or not waves are clean enough to surf at Balevullin (Tiree), you can view an alternative image that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. During a typical April, swells large enough to cause surfable waves at Balevullin (Tiree) run for about 76% of the time.

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