A six-hour window shift reduced the next-day wind-gain contrast after offshore eastern Pacific rapid intensification in 1982-2023

We compared next-day wind gain after rapid and moderate prior-day intensification in fixed IBTrACS v04r01 tracks. We selected tropical offshore windows in 1982-2023 and adjusted for current wind, location, month and year. In 5,112 eastern Pacific windows from 588 storms, the rapid-minus-moderate contrast was 7.12 kt, with a storm-cluster 97.5% interval of 4.35 to 9.88 kt. In the subset with six more hours of data, moving the outcome from hours 0-24 to hours 6-30 reduced the contrast from 7.27 to 2.34 kt. The paired change was -4.93 kt, with an interval of -6.00 to -3.85 kt. The later contrast had an interval of -0.45 to 5.14 kt. The primary Atlantic contrast was uncertain at 1.78 kt (-1.59 to 5.15). These data show that the eastern Pacific association depends on the outcome start time. They do not establish a distinct physical regime or useful forecast skill. Selected complete windows, final wind estimates, model form and unmeasured local conditions limit inference. Source fields, hashes, code, all estimates and a numerical audit are included.

tropical cyclone · rapid intensification · intensity persistence · eastern Pacific · timing sensitivity · IBTrACS