North Atlantic storm

43°41.2′N 034°08.5′W

Waves left about 22 Sep 17:56Z, ± 6 h

Placed by 3 buoys, whose own placements lie within 628 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