Experimental C-Street breaking-wave estimate, reviewed against WaveCast screenshots dated September 21 and 24, 2026. Local breaks can respond differently to the same swell. Live surf forecasts use official NOAA GFS-Wave subsets processed by San Buena. Tides use NOAA Ventura station predictions. This is not Nathan Cool’s formula or a validated surf model.
A simplified shoaling calculation uses swell height and period. NNW has a fitted period correction; the previous SSW adjustment was retained because replacement fits did not improve validation. Longer-period swell can produce a larger estimate even when its offshore height is smaller. Each day shows the highest breaking estimate for each group; swell height, period, and direction describe the component at that same hour. Do not add the two groups’ heights.
Calibration review: 32 daily comparisons per group from two forecast captures, covering 19 distinct dates. In nested testing that excluded each target date from fitting and model selection, NNW differed from the reference midpoints by 0.69 ft on average. Candidate SSW changes did not improve the comparison reliably. These are comparisons with another forecast, not measured surf accuracy. The captures share weather events and their model runs are not verified as identical. Different swell directions and periods still cause day-specific errors.
Ranges are a rounded 80–120% band around the estimate, not statistical confidence limits. Tide, local bathymetry, wind, refraction, and island shadowing are not explicitly modeled. No measured breaking-wave observations were used.
GFS-Wave 0.25° model. NNW and SSW are broad group labels, not narrow compass filters. This site groups west–north swell (247.5°–360°, including 0°) under NNW, and south–southwest swell (112.5° up to 247.5°) under SSW. These are this site’s grouping rules; they are not a reproduction of WaveCast’s unpublished processing. Each hourly component is grouped by direction, then the highest breaking estimate is selected across all three swell ranks.
A missing swell means no matching component was reported, not necessarily a flat ocean. These are the strongest reported matching swells, not summed directional energy. Other directions are excluded. Partial days use available hours. Model initialization and collection times are shown. Output is hourly through forecast hour 120 and three-hourly through hour 384; no artificial hourly values are inserted. The forecast uses a ten-minute cache. Opening swell requests the latest data. If the request fails, a previous model run less than 48 hours old may remain visible with its fetch time and a warning.
Forecasts further out are less certain. Physics background: Coastal Dynamics — wave transformation.
NOAA source data is public-domain material under the NWS use terms. Grouping and experimental breaking-wave estimates are San Buena modifications, not official NOAA products. NOAA does not endorse San Buena.