South Atlantic storm

00°56.5′S 003°04.4′W

Waves left about 21 Sep 13:49Z, ± 17 h

Placed by 2 buoys, whose own placements lie within 78 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