Severe 2023/2024 Winter Subseasonal Weather Extremes Over Eastern China: Two Pathways of ENSO Impacts

Abstract During the 2023/2024 winter, eastern China experienced frequent cold extremes, heavy snowfall, and freezing rain, modulated by the circulation regime of enhanced atmospheric intraseasonal oscillation (ISO). Our results show these severe weather events can be attributed to two pathways of El Niño's influence. The strong ISO cold events were characterized by an amplified Siberian High, developed from a North Atlantic (NA)‐originating Rossby wave train. The El Niño modulated the NA jet stream by strengthening, extending it eastward, and increasing its southwest–northeast tilt, which reinforced cold‐air circulation regime via interactions between the seasonal background flow and ISO perturbations. Meanwhile, El Niño strengthened the western North Pacific anticyclone, enhancing moisture transport for freezing rain formation. The two pathways of El Niño–Southern Oscillation (ENSO) impacts can be found in most ENSO years, implying that ENSO is an important source of subseasonal forecast of extreme cold‐wet events in China.