North Pacific storm

46°43.1′N 152°48.1′E

Waves left about 23 Sep 01:43Z, ± 3 h

Placed by 5 buoys, whose own placements lie within 489 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