North Pacific storm

51°45.3′N 168°15.4′W

Waves left about 25 Sep 04:14Z, ± 1 h

Placed by 9 buoys, whose own placements lie within 287 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