North Pacific storm

27°59.8′N 168°45.8′W

Waves left about 24 Sep 11:11Z, ± 6 h

Placed by 2 buoys, whose own placements lie within 329 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