North Pacific storm

22°34.7′N 178°52.9′W

Waves left about 23 Sep 16:18Z, ± 4 h

Placed by 5 buoys, whose own placements lie within 421 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