North Atlantic storm

50°56.5′N 049°16.3′W

Waves left about 13 Sep 08:27Z, ± 2 h

Placed by 3 buoys, whose own placements lie within 381 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