Statistiques de Surf de Machir Bay (Islay)

The figure shows the range of swells directed at Machir Bay (Islay) over a normal September, based on 3360 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coast so we have chosen the best grid node based on what we know about Machir Bay (Islay), and at Machir Bay (Islay) the best grid node is 25 km away (16 miles). The rose diagram describes 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 were forecast only 13% of the time. Green and yellow show increasing swell sizes and red illustrates biggest swells greater than >3m (>10ft). In each graph, the area of any colour is proportional to how commonly that size swell occurs. The diagram implies that the dominant swell direction, shown by the largest spokes, was W, 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 Machir Bay (Islay) and out to sea. We combine these 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 Machir Bay (Islay), you can select a similar diagram that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. During a typical September, swells large enough to cause surfable waves at Machir Bay (Islay) run for about 87% of the time.

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