Role of large and local scale drivers in the recent rise in heavy precipitating events over western India

Over the recent decades, the South Asian monsoonal environment has evolved, leading to a rise in heavy precipitation events over the Indian subcontinent. These events have increased in frequency and intensity, particularly over Western India since the 1980s. The present study employs Self-Organizing Map (SOM) clustering to examine atmospheric patterns associated with heavy rainfall over Western India, identifying two key clusters, which have shown a significant rise in occurrence since the 1970s. The first cluster is marked by a large-scale mid-level vortex stretching from the Bay of Bengal to the Arabian Sea, driven by strong easterly anomalies and low-pressure systems (LPS) along central India. In contrast, the other cluster is manifested as a localized system centred over Western India, with low geopotential heights and LPS activity, supported by moisture from the Arabian Sea and regional land evaporation. The development of the first pattern is linked to remote influences such as Indian Ocean Dipole (IOD) events, while local soil moisture conditions influence the second pattern. This study underscores the complex interactions between large-scale dynamics, land-atmosphere coupling, and extreme weather patterns, highlighting the need for enhanced understanding of multis-scale interactions and increased observational networks to improve predictions and management of hydrological extremes in Western India.