The Northwest Hawaii buoy reported swell heights of 23.6 feet at 8:00 p.m. HST. Looking at the forecast model above, we can see that this is slightly larger than the predicted 20.7 feet at 8:00 p.m. The Waimea Bay forecast however, predicts tomorrow’s surf at a significantly smaller 11.8 feet at 16.1 seconds.
Taking a closer look at the Northwest Hawaii forecast, we see that the primary swell direction is 292°, which falls within the Kauai shadow window shown below.
The significantly smaller Waimea Bay swell height forecast (as compared to the Northwest Hawaii buoy) is a result of this shadowing effect. While there will be solid surf on Oahu tomorrow, observed wave heights on Kauai will be significantly larger. The next major swell is forecast to arrive on Thursday and has Eddie officials on watch, but the conditions at the moment look borderline at best.