Ann Street Peaks Swell Statistics, Março: All Swell – Any Wind
The figure shows the range of swells directed at Ann Street Peaks through a typical March, based on 2220 NWW3 model predictions since 2007 (values every 3 hours). The wave model does not forecast wind or surf right at the shore so we have chosen the best grid node based on what we know about Ann Street Peaks, and at Ann Street Peaks the best grid node is 45 km away (28 miles).
The rose diagram illustrates the distribution of swell directions and swell sizes, while the graph at the bottom shows the same thing without direction information. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These occurred only 3% of the time. Green and yellow represent increasing swell sizes and biggest swells greater than >3m (>10ft) are shown in red. In each graph, the area of any colour is proportional to how often that size swell occurs.
The diagram indicates that the dominant swell direction, shown by the longest spokes, was ESE (which was the same as the prevailing wind direction). Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Ann Street Peaks and away from the coast. 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 surfable at Ann Street Peaks, you can view an alternative image that shows only the swells that were forecast to coincide with glassy or offshore wind conditions. Over an average March, swells large enough to cause good for surfing waves at Ann Street Peaks run for about 97% 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.