Abrupt shifts from drought to extreme precipitation – a case of compound extremes – pose significant challenges to society and natural systems. Here, we investigate mechanisms driving the abrupt termination of droughts through extreme precipitation and the subsequent rapid post-drought transition to wet extremes, with a focus on the key role of weather systems. We find that intense and prolonged droughts are more likely to end through extreme precipitation than weaker and shorter droughts. Abrupt shifts from drought to wet are most frequent in storm track affected regions, where sustained circulation anomalies inhibiting precipitation are rapidly replaced by precipitation-bearing weather systems. Concurrent weather systems are important for these transitions, with the co-occurrence of weather systems (e.g., cyclones, fronts, atmospheric rivers, etc.) facilitating faster shifts from drought to wet conditions. Specifically, in storm track affected regions, concurrent weather systems bring abrupt increases in moisture transport, vertical motion, and water vapor content, increasing the likelihood of extreme precipitation to end droughts. These insights advance our understanding of precipitation variability in a changing climate, providing perspectives for predicting and mitigating compound extreme hydrological events.
 

干旱,极端降水,极端事件,天气系统