Ampang Swell Statistics, June: All Swell – Any Wind
The graph illustrates the range of swells directed at Ampang through an average June, based on 2306 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 Ampang. In the case of Ampang, the best grid node is 14 km away (9 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 show increasing wave sizes. The smallest swells, less than 0.5m (1.5 feet), high are coloured blue. These occurred only 37% of the time. Green and yellow represent increasing swell sizes and red illustrates the largest swells, greater than >3m (>10ft). In both graphs, the area of any colour is proportional to how frequently that size swell happens.
The diagram suggests that the prevailing swell direction, shown by the largest spokes, was SSW, whereas the the most common wind blows from the ESE. Because the wave model grid is offshore, sometimes a strong offshore wind blows largest waves away from Ampang and away from the coast. We combine these with the no surf category of the bar chart. To avoid confusion we don't show these in the rose plot. Because wind determines whether or not waves are clean enough to surf at Ampang, you can select a similar diagram that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. In a typical June, swells large enough to cause surfable waves at Ampang run for about 61% 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.