Aln Estuary Swell Statistics, December: All Swell – Any Wind
This chart illustrates the combination of swells directed at Aln Estuary over a normal December and is based upon 2455 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 optimum grid node based on what we know about Aln Estuary, and at Aln Estuary the best grid node is 14 km away (9 miles).
The rose diagram describes the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing but without direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These occurred only 54% of the time. Green and yellow represent increasing swell sizes and red shows the largest swells, greater than >3m (>10ft). In each graph, the area of any colour is proportional to how often that size swell occurs.
The diagram indicates that the most common swell direction, shown by the biggest spokes, was NE, 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 Aln Estuary and offshore. We combine these with the no surf category of the bar chart. To avoid confusion we don't show these in the rose plot. Because wind determines whether or not waves are good for surfing at Aln Estuary, you can load a different image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. During a typical December, swells large enough to cause clean enough to surf waves at Aln Estuary run for about 23% 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.