Abstract: Extreme precipitation events (EPEs) in the Indian Himalayas continue to trigger devastating floods, landslides, and infrastructure losses, underscoring the need for improved scientific understanding and prediction. This study examines the multiscale atmospheric processes responsible for EPEs, highlighting the interplay between large-scale circulation features and local dynamical drivers. Our results show that EPEs are strongly influenced by distinct uppertropospheric gyres and a prominent zonal wave pattern that establishes a favorable synoptic environment. This configuration enhances southward trough intrusions, strengthens the convergence of moisture-laden winds from surrounding ocean basins, and increases moisture availability. The accompanying southward propagation of cyclonic vorticity further supports northward moisture transport, emphasizing the critical role of tropical–extratropical interactions in initiating extreme Himalayan rainfall. At regional scales, moisture-budget diagnostics reveal that vertical moisture advection dominates, demonstrating the importance of localized dynamical processes. Intensifying diabatic heating over the Western Himalayas promotes deep convection and vertical motion, while shifts in the Intertropical Convergence Zone (ITCZ) modulate convective intensity and spatial distribution. Additionally, Quasi-Resonant Amplification (QRA) is linked to some of the most persistent and severe EPEs. These insights support advances in highresolution forecasting tools and early-warning systems tailored for Himalayan terrain.

Keywords: Western Himalayas, Extreme Precipitation, Physical drivers, Tropical –Extratropical interaction

Bio: Dr. Raju Attada is an Associate Professor at the Indian Institute of Science Education and Research (IISER) Mohali. His research focuses on extreme weather events, high-resolution numerical modelling, AI/ML applications, and hydro-meteorological hazards over the Indian Himalayas. His group works on advancing modeling techniques and developing high-resolution early warning systems for mountain regions. He received his Master’s degree in Meteorology from Andhra University in 2008 and completed his Ph.D. at the Indian Institute of Tropical Meteorology, Pune, focusing on the impact of data assimilation on the prediction of Indian Summer Monsoon rainfall. Dr. Attada has published nearly 95 papers in international peer-reviewed journals and serves on the editorial boards of Scientific Reports, Discover Atmosphere, and Journal of Hydrology. He is also an active member of several leading meteorological and geoscience societies worldwide.