North Atlantic storm

45°41.4′N 031°13.5′W

Waves left about 22 Sep 05:15Z, ± 4 h

Placed by 2 buoys, whose own placements lie within 199 mi 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