North Pacific storm

12°33.1′N 136°24.3′W

Waves left about 31 Aug 07:14Z, ± 5 h

Placed by 2 buoys, whose own placements lie within 211 nmi of it

Each buoy places the storm from how its swell's period shortened as it arrived: the longest waves travel fastest. Fronts are drawn at deep-water group speeds along great circles, and stop at land. How it is worked out