Statistiques de Houle pour Anna Maria Key, Novembre: Toutes Houles – Tous Vents
The graph illustrates the variation of swells directed at Anna Maria Key over a normal November. It is based on 2384 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 optimum grid node based on what we know about Anna Maria Key, and at Anna Maria Key the best grid node is 26 km away (16 miles).
The rose diagram shows the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing but lacks 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 68% of the time. Green and yellow show increasing swell sizes and largest swells greater than >3m (>10ft) are shown in red. In both graphs, the area of any colour is proportional to how commonly that size swell occurs.
The diagram implies that the prevailing swell direction, shown by the biggest spokes, was NW, whereas the the most common wind blows from the NE. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Anna Maria Key and out to sea. We combine these with the no surf category of the bar chart. To simplify things we don't show these in the rose plot. Because wind determines whether or not waves are good for surfing at Anna Maria Key, 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 November, swells large enough to cause clean enough to surf waves at Anna Maria Key run for about 32% 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.