North Atlantic storm

25°15.1′N 051°24.5′W

Waves left about 9 Sep 01:04Z, ± 11 h

Placed by 2 buoys, whose own placements lie within 110 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