North Pacific storm

30°31.6′N 169°02.6′W

Waves left about 24 Sep 13:59Z, ± 4 h

Placed by 3 buoys, whose own placements lie within 397 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