Super Typhoon Mangkhut (2018) was an exceptional western North Pacific storm that maintained super-typhoon intensity while moving rapidly westward at unusually low latitudes. Using a statistical-dynamical downscaling framework, we examine how this unusual evolution was controlled by steering flows across multiple time scales and how its intensity responded to the environmental conditions along the track. To isolate the effects of steering at different time-scales, band-pass filtering and vortex removal techniques are used to drive downscaling of Mangkhut. The seasonal flow derived from the 60-day low pass filter produces slow, recurving tracks. Including shorter time-scale variability strengthens the westward steering, shifts tracks equatorward, and yields landfalls closer to the Philippines. Sensitivity experiments with multiple initialization dates confirm that these behaviors depend primarily on flow time scale. The statistical intensity model reproduces Mangkhut’s rapid intensification and its weakening near landfall at the Philippines, with the largest contributions from the potential intensity deficit and autoregressive persistence. These results indicate that favorable thermodynamic conditions, together with weak adverse effect of wind shear, is crucial to Mangkhut attainment of super-typhoon intensity. Overall, the results demonstrate that subseasonal and synoptic circulation anomalies, together with track-dependent intensity environment, are essential for understanding and predicting such storms.

Tropical cyclones;,Downscaling model;,Subseasonal steering flow