Pacific City-Gas Chambers Swell Statistics, July: All Swell – Any Wind
The figure shows the combination of swells directed at Pacific City-Gas Chambers through a typical July and is based upon 1984 NWW3 model predictions since 2006 (values every 3 hours). The wave model does not forecast wind and surf right at the coastline so we have chosen the most applicable grid node based on what we know about Pacific City-Gas Chambers, and at Pacific City-Gas Chambers the best grid node is 34 km away (21 miles).
The rose diagram shows the distribution of swell sizes and directions, while the graph at the bottom shows the same thing but without direction information. Five colours illustrate increasing wave sizes. Blue shows the smallest swells, less that 0.5m (1.5 feet) high. These were forecast only 7% of the time. Green and yellow illustrate increasing swell sizes and red shows biggest swells greater than >3m (>10ft). In either 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 prevailing wind blows from the NW. Because the wave model grid is out to sea, sometimes a strong offshore wind blows largest waves away from Pacific City-Gas Chambers and offshore. 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 surfable at Pacific City-Gas Chambers, you can select a similar diagram that shows only the swells that were predicted to coincide with glassy or offshore wind conditions. Over an average July, swells large enough to cause good for surfing waves at Pacific City-Gas Chambers run for about 93% 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.