Overview
- The Mexican Servicio Meteorológico Nacional (SMN) forecasts a week of widespread rain from September 7–11 driven by the Mexican monsoon and tropical wave 37, with the highest local totals expected midweek.
- Authorities in Mexico City raised citywide alerts on September 6–7, upgrading Iztacalco, Iztapalapa and Venustiano Carranza to orange and placing the remaining 13 alcaldías under yellow for heavy rain, hail and electrical storms.
- Sonora is forecast to see several days of storms that peak on Thursday, September 10, when some central areas could receive 75–150 mm and face flash flooding, strong winds and lightning.
- States including Jalisco and Guanajuato face repeated storms and localized intense accumulations that could cause urban flooding, landslides in vulnerable terrain and disruptions to roads and drainage.
- Regional agencies in Peru and Argentina issued parallel warnings for highland rain, snow and strong winds between September 8–10, and forecasters say a very strong El Niño in 2026–27 could amplify these extremes and heat episodes in coming months.