North Pacific storm

45°26.9′N 170°07.8′W

Waves left about 25 Sep 00:34Z, ± 2 h

Placed by 9 buoys, whose own placements lie within 253 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