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<p>Unprecedented heavy rainfall events over the Arabian Peninsula during mid-April 2024 caused flooding, loss of life and disruptions in various sectors. In the present paper, we elucidate the causative atmospheric dynamics and assess the fidelity of the operational numerical weather prediction (NWP) models in predicting these events. Our analysis reveals that an amplified mid-latitude wave activity over the Atlantic Ocean triggered two successive anticyclonic Rossby wave-breaking events, forming cutoff lows over the Atlantic–Northwest Africa on April 15 and the Arabian Peninsula on April 16. A trough in the upper level westerlies intensified into a potential vorticity (PV) streamer on April 15 and evolved into a cutoff low on April 16 over the northwest Arabian Peninsula, creating favourable conditions for heavy rainfall. Given the upper air atmospheric condition, moisture inflow from the Arabian Sea, driven by lower-level anticyclonic circulation, fuelled the extreme rainfall events. Assessment of the fidelity of the NWP models in predicting heavy rainfall events suggests capturing the events by models; however, the magnitude varied from model to model with a considerable underestimation. The probabilistic forecast for the heavy rainfall threshold using quantitative precipitation forecast (QPF) suggests a higher probability of the event occurrence. It suggests that the forecast accuracy of the extreme rainfall event improved with extended lead times when we consider a QPF, offering crucial insights for early warning and preparedness efforts.</p> Graphical Abstract <p>The planetary-scale Rossby wave breaking along with the favourable atmospheric conditions and moisture transport led to the extreme rainfall event over the middle east during April 2024. The circulation anomalies and its vertical extension over the northwestern region of the Arabian Peninsula created the favourable conditions for the atmospheric instability. At lower atmospheric levels, an anticyclonic circulation over the northern Arabian Sea facilitated moisture transport into the region. The main source of this moisture was Arabian Sea as an outflow of the anticyclone circulation and the Red Sea, supported by westerly winds linked to an upper-level trough.</p>

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On the Extreme Rainfall Over the Arabian Peninsula in April 2024: Dynamics and NWP Model Performance

  • 期刊论文

  • 发表日期：

    2025年9月30日

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  • Priya Kumari,
  • S. D. Sanap,
  • Pushpa Saroja

摘要

Unprecedented heavy rainfall events over the Arabian Peninsula during mid-April 2024 caused flooding, loss of life and disruptions in various sectors. In the present paper, we elucidate the causative atmospheric dynamics and assess the fidelity of the operational numerical weather prediction (NWP) models in predicting these events. Our analysis reveals that an amplified mid-latitude wave activity over the Atlantic Ocean triggered two successive anticyclonic Rossby wave-breaking events, forming cutoff lows over the Atlantic–Northwest Africa on April 15 and the Arabian Peninsula on April 16. A trough in the upper level westerlies intensified into a potential vorticity (PV) streamer on April 15 and evolved into a cutoff low on April 16 over the northwest Arabian Peninsula, creating favourable conditions for heavy rainfall. Given the upper air atmospheric condition, moisture inflow from the Arabian Sea, driven by lower-level anticyclonic circulation, fuelled the extreme rainfall events. Assessment of the fidelity of the NWP models in predicting heavy rainfall events suggests capturing the events by models; however, the magnitude varied from model to model with a considerable underestimation. The probabilistic forecast for the heavy rainfall threshold using quantitative precipitation forecast (QPF) suggests a higher probability of the event occurrence. It suggests that the forecast accuracy of the extreme rainfall event improved with extended lead times when we consider a QPF, offering crucial insights for early warning and preparedness efforts.

Graphical Abstract

The planetary-scale Rossby wave breaking along with the favourable atmospheric conditions and moisture transport led to the extreme rainfall event over the middle east during April 2024. The circulation anomalies and its vertical extension over the northwestern region of the Arabian Peninsula created the favourable conditions for the atmospheric instability. At lower atmospheric levels, an anticyclonic circulation over the northern Arabian Sea facilitated moisture transport into the region. The main source of this moisture was Arabian Sea as an outflow of the anticyclone circulation and the Red Sea, supported by westerly winds linked to an upper-level trough.