Tropical-extratropical interactions: the atmospheric dynamics behind Dubai's extreme precipitation in April 2024

Extreme precipitation events (EPEs) are becoming more frequent and intense under a warming climate, posing escalating risks to arid urban regions, emphasising the critical need to understand their atmospheric triggers. This study investigates the large-scale atmospheric dynamics behind an EPE that occurred in Dubai on April 16 2024, leading to catastrophic flooding and substantial economic losses. We employ a multifaceted approach to examine daily precipitation anomalies and large-scale atmospheric conditions preceding the EPE. Backward trajectories, simulated using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model, are analysed to trace the origin and transport of air masses contributing to the event. Spatial patterns and vertical cross-sectional analyses of atmospheric diagnostic variables are conducted to explain the EPE dynamics. The findings reveal that a combination of cold air anomalies aloft and warm air anomalies in the mid and lower troposphere, coupled with an intrusion of cold air from the north, likely driven by a subtropical jet (STJ)-induced trough, led to baroclinic instability and triggered strong convective activity, resulting in the EPE. Strong negative geopotential height anomalies across various pressure levels indicate a barotropic atmospheric structure. This configuration facilitated strong low-level convergence and upper-level divergence, promoting a chimney-like mechanism that enhanced moisture transport from surrounding water bodies—the Arabian Gulf, Arabian Sea, and Red Sea. Additionally, the progressive intensification of cyclonic vorticity further enhanced the deep convective circulation anomalies, contributing to the development of the EPE. These findings suggest that identifying specific atmospheric precursors may improve the predictability of the EPEs in Dubai.