Statistiques de Houle pour Ardnave Point and Bay (Islay), Juillet: Toutes Houles – Tous Vents
This picture illustrates the combination of swells directed at Ardnave Point and Bay (Islay) through a typical July and is based upon 2480 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 best grid node based on what we know about Ardnave Point and Bay (Islay). In the case of Ardnave Point and Bay (Islay), the best grid node is 18 km away (11 miles).
The rose diagram shows the distribution of swell sizes and swell direction, 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 occurred only 17% of the time. Green and yellow show increasing swell sizes and red shows largest swells greater than >3m (>10ft). In either graph, the area of any colour is proportional to how commonly that size swell was forecast.
The diagram implies that the prevailing swell direction, shown by the longest spokes, was W, whereas the the most common wind blows from the WSW. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Ardnave Point and Bay (Islay) and offshore. We group 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 good for surfing at Ardnave Point and Bay (Islay), you can view an alternative image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. Over an average July, swells large enough to cause clean enough to surf waves at Ardnave Point and Bay (Islay) run for about 13% 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.