A Slowdown in Translation Speed of Western North Pacific Tropical Cyclones Undergoing Rapid Intensification

Abstract This study examines long‐term trends in western North Pacific (WNP) tropical cyclones (TCs) experiencing rapid intensification (RI) from 1971 to 2022. Although there is only a weak slowdown for all intensifying WNP TCs, the average translation speed for RI TCs has significantly decelerated over the RI main development region (7.5°–25°N, 115°–160°E). This slowdown is primarily due to increasing RI probabilities for slower‐moving TCs. By contrast, the RI probability of faster‐moving TCs remains virtually unchanged. These differences in RI trend probabilities between slow‐moving and fast‐moving TCs are primarily linked to a deepening of the WNP mixed layer. TC‐induced sea surface temperature cooling tends to weaken when the mixed layer is deep. During the intensification stage, the deeper mixed layer is more critical for slower‐moving TCs than for faster‐moving TCs. Our findings suggest that RI probabilities for slow‐moving WNP TCs may continue to increase in a future warming climate.