Synoptic and Thermodynamic Analysis of Exceptional Wet‐Snow Event in Seoul Metropolitan Area, Korea on 27–28 November 2024

Abstract

This study investigates the synoptic and thermodynamic mechanisms that contributed to an exceptional late‐autumn wet‐snow event in the Seoul Metropolitan Area (SMA), Republic of Korea, on 27–28 November 2024, with a focus on the interplay among the low‐level moisture advection, near‐surface thermal stratification, and upper‐level dynamical forcing. By combining surface observations, reanalysis data, radar observations, and high‐resolution weather prediction model simulations, this study finds that the wet‐snow event was driven by a temporally varying synoptic environment around SMA, the central part of the Korean Peninsula, characterized by a deep mid‐latitude trough, sustained moisture transport from the Yellow Sea, and a shallow near‐surface melting layer over the SMA. Vertical thermodynamic profiles indicate that partial melting near the surface contributed to wet‐snow formation under marginal near‐freezing conditions. These results suggest that while large‐scale synoptic dynamics initiated the event, mesoscale thermodynamic factors, particularly the boundary‐layer temperature and humidity structure, played a crucial role in modulating the precipitation phase and intensity. This case study elucidates the mechanisms governing wet‐snow events under marginal thermal environments.