North Pacific storm

21°55.7′N 126°32.9′W

Waves left about 26 Sep 13:30Z, ± 3 h

Placed by 2 buoys, whose own placements lie within 204 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