In August 2022, Pakistan experienced unprecedented monsoon rains, leading to devastating floods and landslides affecting millions. While previous research has mainly focused on the contributions of seasonal and synoptic anomalies, this study elucidates the dominant influences of tropical and extratropical intraseasonal oscillations on both the occurrence and subseasonal prediction of this extreme rainfall event. Our scale-decomposed moisture budget analysis revealed that intense rainfall in Pakistan was triggered and sustained by enhanced vertical moisture transport anomalies, primarily driven by interactions between intraseasonal circulation anomalies and the prevailing background moisture field when tropical and mid-latitude systems coincided over Pakistan. Evaluation of subseasonal-to-seasonal prediction models further highlighted the critical role of tropical intraseasonal modes in causing this extreme rainfall event in Pakistan. Models that accurately predicted northward-propagating intraseasonal convection with a forecast lead time of 8–22 days demonstrated good skill in predicting the extreme event over Pakistan.

2022 年 8 月，巴基斯坦经历了前所未有的季风降雨，导致毁灭性的洪水和山体滑坡影响了数百万人。虽然以前的研究主要集中在季节性和天气异常的贡献上，但本研究阐明了热带和温带季节内振荡对这种极端降雨事件的发生和次季节预测的主要影响。我们的尺度分解水汽收支分析显示，巴基斯坦的强降雨是由增强的垂直水汽输送异常触发和维持的，这主要是由热带和中纬度系统在巴基斯坦上空重合时季节内环流异常与盛行的背景水汽场之间的相互作用驱动的。对次季节到季节预测模型的评估进一步强调了热带季节内模式在导致巴基斯坦极端降雨事件中的关键作用。准确预测向北传播的季节内对流（预测提前期为 8-22 天）的模型在预测巴基斯坦上空的极端事件方面表现出良好的技能。