North Atlantic storm

46°03.5′N 033°52.0′W

Waves left about 22 Sep 10:24Z, ± 3 h

Placed by 3 buoys, whose own placements lie within 304 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