North Pacific storm

18°37.2′N 133°50.6′W

Waves left about 8 Sep 18:58Z, ± 5 h

Placed by 2 buoys, whose own placements lie within 264 mi 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