Ardnave Point and Bay (Islay) Swell Statistics, May: All Swell – Any Wind
The figure illustrates the variation of swells directed at Ardnave Point and Bay (Islay) over a normal May and is based upon 2200 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind and surf right at the coast so we have chosen the most applicable grid node based on what we know about Ardnave Point and Bay (Islay), and at Ardnave Point and Bay (Islay) the best grid node is 18 km away (11 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 represent increasing wave sizes. Very small swells of less than 0.5m (1.5 feet) high are shown in blue. These happened only 21% of the time. Green and yellow show increasing swell sizes and red represents largest swells greater than >3m (>10ft). In each graph, the area of any colour is proportional to how frequently that size swell occurs.
The diagram suggests that the dominant swell direction, shown by the largest spokes, was W, whereas the the most common wind blows from the SW. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Ardnave Point and Bay (Islay) and away from the coast. We combine 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 clean enough to surf at Ardnave Point and Bay (Islay), 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 May, swells large enough to cause surfable waves at Ardnave Point and Bay (Islay) run for about 24% of the time.
IMPORTANT: Beta version feature! Swell heights are open water values from NWW3. There is no attempt to model near-shore effects. Coastal wave heights will generally be less, especially if the break does not have unobstructed exposure to the open ocean.