Northward shift of pre-monsoon zonal winds exacerbating heatwaves over India

India has observed increasingly persistent heat extremes in recent decades. North-Central India, a highly populated region prone to heatwaves, has experienced record maximum temperatures (>48°C) during the pre-monsoon season. While studies have shown positive trends in heatwaves due to rising air temperature, we identify a shift in pre-monsoon mean daily maximum temperature over North-Central India, resulting in an increase in temperature by 0.7°C post-1998. The jump in temperature is associated with a northward migration of the subtropical westerly jet since 1998. We find that the meridional shift in the subtropical westerly jet explains more than 25% of the variability in heatwave characteristics over North-Central India, implying that the increase in heatwaves post-1998 is associated with a northward shift of the jet. These findings highlight that the exacerbation of heatwaves in North-Central India is driven by atmospheric dynamical changes triggered by a regime shift, further compounded by global warming.