Understanding the trans‐season impact of Tibetan plateau snow cover anomalies on tropical cyclogenesis over the western North Pacific

Abstract This study investigates the trans‐seasonal connection between boreal spring (MAM) Tibetan Plateau snow cover (TPSC) and subsequent summer–fall (JJASON) western North Pacific (WNP) tropical cyclone (TC) formation during 1979–2020. It is found that increased MAM TPSC suppresses TC formation in the southeastern WNP. The remote influence of MAM TPSC is transferred by anomalous atmospheric heating/cooling and tropical WNP sea surface temperature (SST) anomalies. Specifically, excessive TPSC enhances surface upward short‐wave radiation reflection, inducing atmospheric cooling above the Plateau. This atmospheric cooling over the Tibetan Plateau could lead to enhancement and southward extension of an atmospheric Rossby wave train that propagates to the WNP, generating an anomalous lower‐level anticyclone and an upper‐level cyclone. Through a positive air–sea feedback mechanism, this atmospheric pattern persists into the JJASON season. Consequently, the combined effect of lower‐tropospheric easterlies and upper‐tropospheric westerlies on the southern flank of these anomalies enhances vertical wind shear over the southeastern WNP, thereby inhibiting TC genesis during JJASON.