North Atlantic storm

28°51.7′N 066°03.7′W

Waves left about 7 Sep 22:18Z, ± 5 h

Placed by 2 buoys, whose own placements lie within 197 nmi 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