On the contrasting springtime extremes in India: Heatwaves and hailstorms in 2022 and 2023

Abstract The spring heatwave over the Indian region in 2022 was unprecedented in intensity and scale, severely affecting millions of people and various sectors, including health and agriculture. In contrast, spring 2023 experienced fewer heatwaves, with higher than normal precipitation and widespread hailstorms across central and northwest India. This study explores the physical mechanisms that are responsible for these contrasting patterns. In the spring of 2022, La Niña conditions prevailed, leading to a poleward shift of the subtropical westerly jet (STWJ). This shift, combined with an upper‐air anticyclonic circulation and associated divergence over central and northwest India, resulted in subsidence and adiabatic heating, leading to extreme heatwave conditions and below‐normal precipitation. In contrast, during the spring 2023, the emergence of El Niño conditions caused the STWJ to shift equatorward. This shift invigorated a cyclonic circulation, with a trough in the upper‐level westerlies and a lowering of the zero‐degree isotherm over central and northwest India. In addition to upper‐level circulation changes, the convergence of moisture at lower levels due to moisture inflow from the Bay of Bengal and the Arabian Sea caused convective instability, leading to hailstorms. The fidelity of coupled dynamical climate models in forecasting the contrasting temperature and precipitation patterns during spring 2022 and 2023 has also been evaluated. This study highlights the significant role of the El Nino–Southern Oscillation (ENSO) in influencing spring weather and climate variability across the Indian region.