Characteristics and formation mechanisms of the widespread extreme gale weather process in China during April 11-13, 2025

A widespread gale process occurred across northern and central-eastern China from April 11 to 13, 2025. Based on conventional observations, wind profiler data, and reanalysis data, this study presents the observational characteristics, synoptic-scale and mesoscale mechanisms, and contributing factors to the extremity of wind gales. The results are as follows. This process was characterized by extensive coverage, prolonged duration, exceptional intensity, record-breaking extremity, progressively intensifying wind gusts, and concurrent multiple types of hazardous weather phenomena. Sixty-four national-level meteorological stations recorded historic maximum gust speeds, with the maximum reaching 46.8 m·s⁻¹. The primary synoptic systems responsible for this process were a large-scale southward-moving surface anticyclone, an upper-level cold vortex, and surface cyclones generated by baroclinic disturbances, constituting a typical case of extensive cold-air outbreak coupled with baroclinic disturbance development. The synoptic-scale formation mechanism involved mid-tropospheric vorticity advection and lower-to-middle tropospheric strong thermal advection. The extremity of this process was attributed to exceptionally intense large-scale anomalies of cold and warm air masses and their frontal confrontation, which generated extreme baroclinicity that subsequently established extensive, steep geopotential height gradients and vertically coupled jets. The thermodynamic effects induced by extensive high-altitude regions, particularly the Loess Plateau, acted to impede the advancement of the gale zone along the cold air front. However, the mesoscale downdraft of lee waves generated localized high wind gusts through downward momentum transport. Strong vertical wind shear triggered vigorous turbulent motions, inducing strong vertical mixing. Simultaneously, mesoscale waves produced intense downward motion. These combined dynamical processes facilitated the downward transport of upper-level momentum to the surface, generating localized extreme wind gusts.