The Servicio Meteorológico Nacional forecast on August 31 that the Mexican monsoon and atmospheric instability over the northwest would drive simultaneous extremes: torrential rains of 50 to 75 mm across a wide arc of Pacific and central states, and maximum temperatures between 40 and 45 degrees Celsius in parts of the northwest, northeast and Oaxaca.

The heaviest rainfall zone runs from the northwest coast through the Pacific slope and into the heartland. Southern Baja California Sur, northern Sonora, western Chihuahua, northern and central Sinaloa, and western Durango are in the rain band, as are central and southern Nayarit, and eastern, central and western Jalisco. Colima, and northern, central and southern Michoacán are also in the forecast, along with central, eastern and southeastern Guanajuato, central, western and southern Querétaro, southwestern Hidalgo, southern Veracruz, eastern Oaxaca, and central and southern Chiapas. The SMN also listed electrical discharges and wind gusts as hazards for Baja California Sur, Sonora, Chihuahua, Durango, Sinaloa and Nayarit.

The heat warning covers a separate but overlapping set of states: Baja California, Sonora, Chihuahua, Sinaloa, Coahuila, Nuevo León, Tamaulipas and Oaxaca face the 40-45 C range. The read here is that Sonora, Chihuahua and Sinaloa appear to sit under both alerts at once, facing flood risk in specific zones while broader daytime temperatures climb toward 45 C. Campeche and Yucatán also appear in multiple rainfall reports, though the SMN's most detailed zonal breakdown did not name specific subregions in those states.}