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Abstract

On April 16, 2024, Dubai and surrounding regions experienced unprecedented rainfall, with some areas receiving up to 2.5 times their average annual rainfall in just 24 h, leading to devastating floods and a tragic loss of life. This study investigates the meteorological mechanisms behind this extreme event using multiple reanalysis datasets. This work identifies the key roles played by a deep cold-core cut-off low (COL) system and an anomalous northward shift of the Intertropical Convergence Zone (ITCZ). The COL, originating from the subtropical jet over Saudi Arabia, combined with an intensified Siberian High, created a strong surface pressure gradient and facilitated the influx of moist tropical air into the region. This interaction drove instability, deep convection, and atmospheric river (AR) activity, resulting in record-breaking precipitation. Observations indicate that the COL was characterized by high potential vorticity (∼7.5 PVU), low temperatures (∼204K) at the tropopause, and enhanced stratosphere-troposphere exchange processes. Aerosol optical depth measurements suggest significant stratospheric aerosol injection, likely amplifying the cooling effect in the lower stratosphere. Due to the high potential for deep convection associated with strong updrafts, the tropospheric air was transported across the tropopause during the folding. This study highlights the coupling of tropical and mid-latitude weather systems, exacerbated by climate change, as a crucial driver of such extreme hydrometeorological events. Improved understanding of these mechanisms is vital for enhancing predictive capabilities and mitigating risks in similar arid regions. This study contributes to identifying the occurrence and dynamics of cold weather in subtropical regions, as opposed to a strong warming trend.