Moisture from US Corn Belt fuels more intense convective storms

The US Corn Belt is among the world’s most productive agricultural regions and a global hotspot for mesoscale convective systems (MCSs), which supply vital growing season rainfall but also drive hazardous flooding. While evapotranspiration (ET) from shallow groundwater, extensive croplands, and irrigation is known to influence regional precipitation, its role in fueling convective storms remains poorly understood. Here we use a high-resolution regional climate model coupled with an advanced water vapor tracer to track moisture from Corn Belt ET into individual convective storms. We find that the integrated groundwater-crop-irrigation interactions amplify MCS frequency by 24-35%, extend storm lifetime by up to 10%, and accelerate storm movement. Moisture from Corn Belt ET enhances the warm-moist inflows, sustaining convective cells and enhancing precipitation near the storm center, with more pronounced effects in stronger storms. These findings highlight the significant role of shallow groundwater and agricultural activities in intensifying convective storms, creating cascading hazards that threaten water and food security.