North Atlantic storm

36°09.8′N 061°33.7′W

Waves left about 28 Sep 23:34Z, ± 3 h

Placed by 2 buoys, whose own placements lie within 196 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