North Atlantic storm

59°48.5′N 014°38.3′W

Waves left about 25 Sep 00:09Z, ± 5 h

Placed by 3 buoys, whose own placements lie within 414 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