Local Land‐Atmosphere Interactions Precondition Moist and Dry Heatwaves Under Large‐Scale Subsidence Over the Indo‐Gangetic Plains

Abstract Increase in pre‐monsoon heatwaves over the Indo‐Gangetic Plains (IGP) of India threatens life and ecosystems. We investigate the sufficiency of large‐scale anticyclones in forming moist and dry heatwaves by analysing local land‐atmospheric conditions prior to 10 heatwaves in IGP. Using Eulerian temperature decomposition, we show that horizontal heat advection (remote) process contributes minimally to both heatwave types compared to diabatic and adiabatic (local) processes. Antecedent factors highlight the critical role of pre‐monsoon showers, followed by nocturnal low‐level clouds and surface moisture, creating a conducive environment for moist heatwaves. In contrast, dry heatwaves form due to anticyclonic conditions, high sensible heat flux, lack of moisture advection, and cloud‐free conditions. This study highlights the role of local land‐atmosphere interactions in triggering the onset of heatwaves and help in distinguishing heatwave regions from adjacent non‐heatwave regions. Monitoring these precursors is essential for developing reliable early warning systems to improve heatwave detection and response.