North Pacific storm

15°06.1′N 133°36.6′W

Waves left about 5 Sep 22:55Z, ± 5 h

Placed by 4 buoys, whose own placements lie within 318 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