North Atlantic storm

37°31.7′N 064°13.7′W

Waves left about 25 Sep 16:51Z, ± 4 h

Placed by 2 buoys, whose own placements lie within 309 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