Aln Estuary Swell Statistics, July: All Swell – Any Wind
This picture describes the combination of swells directed at Aln Estuary over a normal July. It is based on 2479 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast surf and wind right at the shore so we have chosen the best grid node based on what we know about Aln Estuary. In the case of Aln Estuary, the best grid node is 14 km away (9 miles).
The rose diagram describes the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but 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 occurred 55% of the time. Green and yellow illustrate increasing swell sizes and red shows highest swells greater than >3m (>10ft). In each graph, the area of any colour is proportional to how often that size swell happens.
The diagram indicates that the most common swell direction, shown by the biggest spokes, was NE, whereas the the dominant 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 Aln Estuary and out to sea. We lump these in 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 surfable at Aln Estuary, you can load a different image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. During a typical July, swells large enough to cause good for surfing waves at Aln Estuary run for about 10% 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.