North Pacific storm

29°45.4′N 168°25.1′W

Waves left about 11 Sep 23:21Z, ± 4 h

Placed by 2 buoys, whose own placements lie within 287 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