North Pacific storm

48°23.2′N 147°47.5′W

Waves left about 27 Sep 02:05Z, ± 2 h

Placed by 5 buoys, whose own placements lie within 241 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