Does vertical wind shear increase tropical cyclone rain?

Abstract Changes in tropical cyclone (TC) rain induced by vertical wind shear (VWS) have significant implications. Using a 26‐year state‐of‐the‐art precipitation dataset, this study provides a systematic analysis of the responses of TC rain to VWS. Results reveal an unexpected VWS‐induced rain volume enhancement despite reduced TC intensity, with rain volume up to 23% higher in high‐ versus low‐shear conditions. The responses are spatially asymmetric: rainfall increases in the outer region but decreases in the inner core, and enhancements downshear generally outweigh suppressions upshear, yielding a net increase in rain production. Beyond the mean response, VWS also modifies rainfall extremes and storm structure. It reduces the maximum azimuthal mean rain rate, whereas the maximum local rain rate remains largely unchanged and even intensifies slightly in the strongest TCs. The radii of rainfall maxima expand outward with shear, and the peak local rain rate tends to converge with the azimuthal mean maximum at high shear. When adjusted by storm intensity, stronger shear enables higher rain rates, larger rain areas, and greater rain volumes for the same TC intensity. These results challenge the conventional view of shear as purely detrimental to TCs, revealing a dual role: VWS weakens winds but enhances rainfall, potentially mitigating wind damage while amplifying flood risk. This trade‐off underscores the need to account for shear‐induced hydrological impacts in TC hazard assessment and prediction.