Scientists track processes that fuel powerful thunderstorms over U.S. Corn Belt
May 27, 2026 - by David Hosansky
| Impact statement: Scientists are using advanced techniques to better track vertical movements of moisture in the U.S. Corn Belt, which can help improve weather forecasting. |
An international team of scientists has demonstrated how powerful thunderstorm complexes over the U.S. Corn Belt are fueled by moisture rising from the region's fertile fields or just beneath them. The findings can lead to better and longer-term weather forecasts for this critical farming area as well as giving researchers new insights into improving computer models needed to better understand atmospheric processes.
The research, led by scientists at the U.S. National Science Foundation National Center for Atmospheric Research (NSF NCAR), focuses on mesoscale convective systems (MCSs), which are complexes of thunderstorms that span 60 miles or more and persist for many hours. The paper concludes that natural reservoirs of shallow groundwater, coupled with irrigation systems and vast fields of crops across the Corn Belt, increases the frequency of these storm systems by 24-35%. The systems also persist about 10% longer.
MCSs are a critical weather feature of the Corn Belt, providing approximately 40–60% of precipitation during the growing season. Even as these potent storms deliver essential moisture to an agricultural region that produces more than a third of the world's corn, however, they also unleash destructive hazards, including flooding, hail, high winds, and tornadoes.
"Our findings provide a holistic view of how groundwater-crop-irrigation interactions influence the local atmosphere and enhance thunderstorms," said NSF NCAR scientist Zhe Zhang, the lead author. "This is important for better forecasting of severe weather for a major agricultural region and helping with long-term prediction of storm patterns weeks or even months in advance."
Zhang and his colleagues used advanced computer simulations and a specialized algorithm to determine the processes that are fueling the region's thunderstorms. The Corn Belt spans a dozen states in the Midwest and Great Plains, ranging from Ohio in the east to Nebraska in the west.
The study was published in Nature Communications Earth & Environment. In addition to a team of NSF NCAR scientists, it was co-authored by scientists with the Institute for Atmospheric and Climate Science (ETH Zürich) in Switzerland, the Universidade de Santiago de Compostela in Galicia, Spain; and the Hong Kong University of Science and Technology. The work was supported by the National Science Foundation.
Land use and the weather
Previous research has shown that the Corn Belt has become increasingly humid, with more rainfall. But researchers, working with increasingly advanced computer models, have only recently been able to tease out why this is happening.
Zhang led a study last year that looked into how the extensive land use changes and irrigation of the U.S. Corn Belt, coupled with the influence of shallow groundwater left from the retreat of Ice Age glaciers more than 11,000 years ago, have affected local precipitation patterns. Using a unique algorithm that traces the movement of water vapor within computer simulations, he and his colleagues showed how groundwater feeds moisture to the surface, and how leafy crops and evaporation from irrigation systems release it to the atmosphere.
For this new study, Zhang and several of the same co-authors again focused on the Corn Belt to look at the influence of groundwater and agriculture on MCSs.
The scientists turned to a pair of advanced NSF NCAR-based computer models to simulate storms over the Corn Belt during the growing season of April to August. To better understand the influence of the land surface on the atmosphere, they ran two sets of simulations: one that incorporated groundwater, crop growth, and irrigation, and one without those processes.
They ran the models at the NSF NCAR–Wyoming Supercomputing Center. As in their previous study, they applied an algorithm to trace the movement of water vapor in the simulations.
When they compared the simulations to actual weather patterns in the Corn Belt during three years - 2010 (wet), 2011 (normal), and 2012 (dry) - they found that only the simulations with groundwater, corn, and irrigation recreated the real-world storms and were consistent with observations from rain gauges and satellites. The algorithm enabled them to see how moisture from groundwater and agricultural activities increased water vapor and amplified updrafts, fueling atmospheric instability and creating favorable conditions for more powerful and longer-lasting MCSs.
Zhang noted that the research provides an important perspective on the Earth system and can help improve computer models. While many studies look at the movement of weather patterns as they flow horizontally from one place to another, this study focused on the vertical influences of water vapor from beneath the ground to high in the atmosphere.
Such research, combined with Zhang's previous work into the mechanisms behind local precipitation patterns, sheds light on the relative influence of agricultural and other processes that affect rainfall in the Corn Belt, such as moist air blowing in from the Gulf or the amount of groundwater that is pumped during wet and dry periods. Knowing more about the impacts of each of these processes, which vary from one year to the next, can inform planting strategies and water resource allocations.
"It's important to develop a better understanding of the influence of land use changes on local weather, especially in an agriculturally intensive area that is vital for our food supply," Zhang said. "Our findings provide insights for the next generation of models as well as helping to inform water management and the agricultural sector."
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David Hosansky
UCAR Media Relations
UCAR, UCP and NSF NCAR
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