North Pacific storm

43°00.8′N 164°12.8′W

Waves left about 8 Sep 09:01Z, ± 7 h

Placed by 2 buoys, whose own placements lie within 147 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