North Pacific storm

45°41.1′N 140°00.4′W

Waves left about 27 Sep 08:44Z, ± 2 h

Placed by 4 buoys, whose own placements lie within 224 km 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