North Pacific storm

28°42.7′N 132°39.4′W

Waves left about 29 Sep 00:20Z, ± 3 h

Placed by 3 buoys, whose own placements lie within 255 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