Assessing future extreme precipitation risks in northern Mexico and southwestern US
Lourdes Mendoza Fierro1, Hsin-I Chang1, Eylon Shamir2, Christopher L. Castro1,3, Norman Pelak2, Exequiel Rolon4, Sahar Mohsenzadeh Karimi1, Claire Acke1
1 Department of Hydrology and Atmospheric Sciences, The University of Arizona, Tucson, AZ
2 Hydrologic Research Center, San Diego, CA
3 NSF National Center for Atmospheric Research, Boulder, CO.
4 Fresnillo plc, Mexico City, Mexico
As climate change intensifies, understanding its regional impact on extreme precipitation is essential for risk assessment and adaptation planning. Industries such as mining and utilities increasingly rely on climate change reports, yet these are often based on coarse resolution Global Climate Models (GCMs), limiting their applicability for localized assessments. This study enhances regional climate risk evaluation by incorporating high-resolution projections from the North American Coordinated Regional Climate Downscaling Experiment (NA-CORDEX). As the CORDEX regional climate model exhibits a wet bias in precipitation estimates over the NAM region, we apply an observation-based adjustment approach to refine and analyze projected changes in extreme precipitation return periods under the highest emission Representative Concentration Pathway (RCP) 8.5 scenario. Extreme precipitation probability assessments are conducted over the Southwest U.S. and Mexico to understand and highlight the projected change in precipitation magnitude and spatial patterns over the North American monsoon region. Station-based assessment reveals highly region-dependent changes in the frequency of historically rare events. Coastal areas of northern and central Mexico show that future extreme precipitation is becoming more intense, with increases exceeding 50% in some areas. In contrast, regions near the northern Mexican Plateau are projected to experience a reduction in extreme precipitation intensity. Results emphasize the need for high-resolution, observation-based precipitation for comprehensive regional risk assessments to inform effective adaptation strategies. This study highlights the value of region-specific climate assessments in capturing specific hydrometeorological risk. This research provides tailored climate extreme assessment for climate resilience over NAM region.