Aligator Rock Swell Statistics, October: All Swell – Any Wind
This image shows the variation of swells directed at Aligator Rock over a normal October and is based upon 2480 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coastline so we have chosen the most applicable grid node based on what we know about Aligator Rock. In this particular case the best grid node is 42 km away (26 miles).
The rose diagram shows the distribution of swell sizes and directions, 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 happened only 42% of the time. Green and yellow illustrate increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In either graph, the area of any colour is proportional to how commonly that size swell happens.
The diagram implies that the dominant swell direction, shown by the biggest spokes, was NNW, whereas the the prevailing wind blows from the E. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Aligator Rock and away from the coast. 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 surfable at Aligator Rock, 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 October, swells large enough to cause good for surfing waves at Aligator Rock run for about 58% 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.