Statistiques de Surf de Dunedin - St Clair

The figure describes the variation of swells directed at Dunedin - St Clair over a normal November. It is based on 3347 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 most applicable grid node based on what we know about Dunedin - St Clair, and at Dunedin - St Clair the best grid node is 10 km away (6 miles). The rose diagram shows the distribution of swell sizes and swell direction, while the graph at the bottom shows the same thing 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 were forecast only 26% of the time. Green and yellow represent increasing swell sizes and highest swells greater than >3m (>10ft) are shown in red. In either graph, the area of any colour is proportional to how frequently that size swell occurs. The diagram suggests that the prevailing swell direction, shown by the largest spokes, was S, whereas the the dominant wind blows from the WNW. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Dunedin - St Clair and away from the coast. We combine these with the no surf category of the bar chart. To simplify things we don't show these in the rose graph. Because wind determines whether or not waves are surfable at Dunedin - St Clair, you can select a similar diagram that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. During a typical November, swells large enough to cause good for surfing waves at Dunedin - St Clair run for about 74% of the time.

read more