North Pacific storm

15°32.2′N 125°15.4′W

Waves left about 31 Aug 18:12Z, ± 8 h

Placed by 2 buoys, whose own placements lie within 301 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