North Pacific storm

49°12.2′N 146°27.2′W

Waves left about 27 Sep 00:40Z, ± 2 h

Placed by 6 buoys, whose own placements lie within 275 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