Whangaehu River Mouth Surf Stats

The figure illustrates the range of swells directed at Whangaehu River Mouth through an average October. It is based on 3471 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind or surf right at the coastline so we have chosen the best grid node based on what we know about Whangaehu River Mouth, and at Whangaehu River Mouth the best grid node is 51 km away (32 miles). The rose diagram describes the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing but without direction information. Five colours show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These were forecast only 15% of the time. Green and yellow show increasing swell sizes and red represents the largest swells, greater than >3m (>10ft). In each graph, the area of any colour is proportional to how commonly that size swell was forecast. The diagram implies that the prevailing swell direction, shown by the longest spokes, was W, whereas the the most common wind blows from the WNW. Because the wave model grid is away from the coast, sometimes a strong offshore wind blows largest waves away from Whangaehu River Mouth and out to sea. We combine these with the no surf category of the bar chart. To avoid confusion we don't show these in the rose graph. Because wind determines whether or not waves are clean enough to surf at Whangaehu River Mouth, you can select a similar diagram that shows only the swells that were expected to coincide with glassy or offshore wind conditions. In a typical October, swells large enough to cause surfable waves at Whangaehu River Mouth run for about 49% of the time.

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