Linking Premonsoon and Monsoon Patterns in Above-Normal and Below-Normal for Central India Monsoon Years

This study investigates the pre-monsoon and monsoon rainfall patterns in central India, with a focus on above-normal and below-normal years. The analysis utilizes gridded rainfall data (1901–2020), ERA-5 reanalysis data (1940–2020), and various atmospheric indicators like Vertically Integrated Moisture Transport (VIMT), Outgoing Longwave Radiation (OLR), Convective Available Potential Energy (CAPE), and upper-air divergence. The findings reveal that above-normal monsoon years are characterized by active pre-monsoon conditions in Northeast and South Peninsular India, with enhanced moisture transport and higher CAPE values, leading to increased rainfall over central India. Conversely, below-normal years show reduced moisture transport, weaker pre-monsoon activity, and suppressed convection, resulting in diminished rainfall. Additionally, VIMT values, OLR, and CAPE analyses highlight the role of moisture dynamics and atmospheric instability in shaping rainfall patterns. Upper-air divergence further supports the enhanced monsoon activity in above-normal years. The study underscores the importance of pre-monsoon conditions, including moisture transport and atmospheric features, in predicting the strength of the monsoon season, offering valuable insights for improving monsoon rainfall forecasts for central India, critical for agriculture and regional economy.