The first significant NNW swell of the 2012-2013 Hawaii winter season is en route, with swell conditions at the Waimea Bay station expected to reach 8 feet at 15 seconds (332°) on Sunday, September 23. With moderate ENE trade winds forecast, conditions could be a touch windy, but the angle is favorable side/off-shore (there’s also a slight possibility of thunderstorms on both Sunday and Monday).
Looking at the charts for Sunday, September 23 (above), you can see that the brunt of the swell is focused more towards the Pacific Northwest and Northern California, with Hawaii receiving mainly sideband energy. Still, it should be enough to produce double-overhead surf along north facing shores and begin to push some of that summer sand around.
A second pulse is lining up behind Sunday’s and is expected to arrive in Hawaii on Thursday, September 27. A South Pacific pulse will also be arriving on Thursday, so there should be plenty of surf to choose from! This animation of the September 21, 2012 swell period forecast clearly shows both swells pushing across the Pacific.
Keep an eye on real-time reports from the Northwest Hawaii station for those long-period forerunners, or better yet, set an alarm to be automatically notified when they arrive!