In this research, we initially examined the key atmospheric circulation pattern influencing the occurrence of dust storms in Northwest China during spring (February–May). We then investigated the drivers impacting atmospheric circulation over the Mongolian Plateau and southern Central Siberia (MPCMS), using NCEP/NCAR reanalysis data and extensive ensemble simulations, and assessed the respective roles of external forces and internal variability. Our results validated a significant inverse correlation between the reduced frequency of spring dust storms in Northwest China post-mid-1980s and heightened geopotential height anomalies over the MPCMS. By scrutinizing five comprehensive ensemble model simulations, we demonstrated that the positive tendencies in atmospheric circulation anomalies over the MPCMS are largely triggered by external forces, accounting for roughly 69.3% of the observed augmentations in the atmospheric circulation index trend from 1954 to 2022. Although the North Atlantic Oscillation is a leading mode of internal variability associated with geopotential height anomalies over the MPCMS, its contribution is comparatively minor. Our findings underline that the primary cause of the decrease in dust storm frequency in Northwest China since the mid-1980s could be ascribed to global warming-related external forces. [ABSTRACT FROM AUTHOR]