Abstract:Based on the surface precipitation data and the ERA5 reanalysis data, the torrential rain that occurred in North China from 23 to 29 July 2025 is investigated from the perspectives of circulation evolution and water vapor conditions. The findings reveal that the torrential rain was a across-warp type process, lasting for seven days, with the main precipitation area zonally spanning over 1000 km. Two primary rain belts were identified, located in the plateau region (secondary terrain area) and the plain region (tertiary terrain area) of North China, respectively. The anomalous large-scale circulation patterns were observed during this precipitation event. The abnormally persistent northward-shifting western Pacific subtropical high (WPSH), a stagnant westerly shortwave trough, and the shear lines generated in the lower troposphere were the key weather systems responsible for the distinct spatio-temporal distribution of precipitation compared to the past typical torrential rain events in North China. The eastward extension of the South Asian high and the westward movement of WPSH dominated the evolution of the torrential rain event and the zonal pattern of precipitation. The low-latitude weather system remained active, and the typhoons Francisco and Co-may, which emerged continuously near East China coastline, transported water vapor in a relay manner with the abnormally westward WPSH. Two water vapor transport belts and convergence zones were formed within the main precipitation area, feeding the two rain belts in the secondary and tertiary terrain regions. The water vapor budget analysis indicates that there was abundant water vapor supply during this torrential rain event, and the abnormally westward WPSH led to a southwestward transport of water vapor. Affected by the advance and retreat of the WPSH, water vapor exhibited obvious cross-topographic transport characteristics.