North Pacific storm

32°39.7′N 152°02.6′W

Waves left about 22 Sep 17:12Z, ± 6 h

Placed by 4 buoys, whose own placements lie within 309 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