Assateague Swell Statistics, Novembre: All Swell – Any Wind
This chart describes the range of swells directed at Assateague through an average November, based on 2387 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the coast so we have chosen the best grid node based on what we know about Assateague. In the case of Assateague, the best grid node is 28 km away (17 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 illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These occurred only 35% of the time. Green and yellow show increasing swell sizes and red illustrates the highest swells, greater than >3m (>10ft). In both graphs, 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 longest spokes, was ESE, whereas the the dominant wind blows from the NW. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Assateague and offshore. We combine these with the no surf category of the bar chart. To keep it simple we don't show these in the rose plot. Because wind determines whether or not waves are good for surfing at Assateague, you can view an alternative image that shows only the swells that were expected to coincide with glassy or offshore wind conditions. In a typical November, swells large enough to cause clean enough to surf waves at Assateague run for about 65% 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.