North Atlantic storm

43°17.5′N 030°00.0′W

Waves left about 22 Sep 16:44Z, ± 2 h

Placed by 8 buoys, whose own placements lie within 299 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