Based on conventional observations and ERA5 reanalysis data, this study analyzes an extreme weather event featuring widespread rain, snow, gales, and temperature drop across central-eastern China during 11—13 April 2025. The cold front passage triggered gales that spread southward from Inner Mongolia to North China and rapidly extended to Jianghuai region, with peak wind speeds and the maximum temperature drop occurring in the afternoon. The southern branch of the jet stream coupled with the northern branch that was characterized by strong cyclonic curvature over the Mongolian plateau. These two stable, quasi-stationary jet branches formed a robust secondary circulation cell, which served as the core dynamic driver for the extreme gales. The northern branch of the jet stream facilitated the downward intrusion of the high-PV (potential vorticity) air to the mid-stratosphere along isentropic surfaces, further enhancing downward transport of kinetic and baroclinic energy. The Mongolian cyclone remained stationary over Northeast China, while the anticyclone over central Mongolia moved southward, leading to dramatic increases in horizontal pressure gradient and directly triggering and sustaining the gales. Within the boundary layer, turbulent activities were dominated by surface heating during the daytime. In the nighttime, the stable stratification inhibited downward transport, strengthening the low-level northerly jet and vertical wind shear. This promoted turbulent mixing via Kelvin-Helmholtz instability and thus sustained nocturnal gales. The phase shift in the North Atlantic Oscillation (NAO) from negative to positive during 7—11 April triggered more efficient Rossby wave energy propagation. The southern branch wave train propagated eastward along the jet axis, while the northern branch wave train extended via Iceland–the Barents Sea–Lake Baikal. The anomalous low over the Barents Sea, cooperating with the Siberian high, guided high-latitude cold air to move southward. On 12 April, the superposition of these two wave trains over North China provided the background energy for the maintenance of the upper-level cold vortex and jet stream. Furthermore, a rapidly moving low pressure system over the Barents Sea on the 8th induced significant reductions in near-surface temperature and humidity along with markedly increased wind speed. This led to a substantial increase in the sea-air temperature difference, accelerating sea ice formation and the release of strong upward sensible and latent heat fluxes. They constituted a positive feedback mechanism, driving the downstream propagation of Rossby wave energy.

On June 14—17 and 21—24, 2023, the North China experienced two of the strongest extremely high events in nearly 40 years, seriously affecting people′s production and life. This article uses reanalysis data to study these two extremely high heatwaves. The results indicate that the heatwaves in North China in June 2023 are both related to the high pressure ridge that moved eastward from the upper reaches of the Eurasian continent. The high pressure ridge was strengthened during the eastward movement due to the influence of the flux of the two wave trains from the north and south. Comparing the contributions of different physical processes to the temperature in North China, it was found that anomalous diabatic heating played a positive role in the formation of both heatwave events, anomalous adiabatic heating had a greater warming effect in the second heatwaves, and anomalous horizontal advection mainly played a cooling role. The wave trains over the Eurasian continent are related to two parts: the southern one mainly propagates eastward along the subtropical zone in the eastern Atlantic Ocean, while the northern one propagates southeastward from Northern Europe. There were anomalous upward movements and anomalous precipitation in the eastern Atlantic and central European during June 4—6 and 17—18, respectively. The results of the LBM demonstrate that the anomalous heat source generated by the latent heat caused by precipitation can stimulate the circulation pattern favorable to heatwaves in North China over the Eurasian continent.