North Pacific storm

34°45.8′N 171°01.0′W

Waves left about 23 Sep 19:44Z, ± 6 h

Placed by 2 buoys, whose own placements lie within 65 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