Mario — 2025

A small tropical low formed from a tropical wave that moved off Central America and organized into a tropical depression by 0600 UTC on 11 September 2025 about 160 n mi southeast of Acapulco, Mexico. The system became Tropical Storm Mario by 0000 UTC 12 September and moved generally west-northwestward near the southwestern Mexican coast. Mario’s circulation was small and the storm degenerated to a trough by 0000 UTC 13 September. The low reorganized and regenerated into a tropical depression by 0600 UTC 14 September and regained tropical-storm strength that day while well south of the southern tip of the Baja California peninsula. Mario weakened over cooler waters and higher wind shear, becoming a post-tropical low by 1200 UTC 16 September and dissipating to a trough by 12 UTC 18 September about 400 n mi west of Cabo San Lázaro, Baja California Sur. Mario did not make a direct landfall as a tropical cyclone. Its closest approach to land occurred on 12 September when the small storm passed just offshore of the southwestern coast of Mexico near Guerrero and Colima. After degeneration and later redevelopment, Mario remained well offshore of the Baja California peninsula and did not produce documented tropical-storm–force landfall there. The storm’s peak intensity occurred at 1200–1800 UTC 15 September when Mario reached estimated maximum sustained winds of 55 kt (about 63 mph) and an estimated minimum central pressure of 994 mb. At peak it was a moderate tropical storm; some satellite intensity estimates ranged from 45–65 kt, making the peak estimate somewhat more uncertain than usual. There were no reports of sustained tropical-storm–force winds measured onshore associated with Mario. Mario and its remnants produced notable rainfall and localized flooding. The heaviest rainfall fell 11–16 September across southwestern and west‑central Mexico and the Baja California peninsula. Maximum reported state totals included 9.06 inches (230 mm) at Laguna de Coyuca, Coyuca de Benítez (Guerrero); 8.58 inches (218 mm) at Gaviotas, Bahía de Banderas (Nayarit); 7.06 inches (179.2 mm) in Colima; and 5.79 inches (147 mm) at Cajón de Peña, Tomatlán (Jalisco). After Mario became a remnant low, lingering moisture produced heavy rains on 16–17 September in Baja California Sur, causing flash and river flooding in towns such as San Ignacio. No specific storm-surge heights were reported in the available observations. There were no confirmed direct fatalities from Mario. Media reports indicate one indirect death by electrocution during flooding on 16 September in San Ignacio, Baja California Sur. Damage reports in southwestern Mexico were generally minor — gusty winds downed trees and power poles in Acapulco and Zihuatanejo with brief outages and some landslides — while more significant flood-related damage in parts of Mulegé and La Paz municipalities and San Ignacio included over 60 homes damaged and a washed-out section of the Transpeninsular Highway. No official monetary damage estimates were available in the report. Noteworthy aspects include Mario’s brief dissipation and later redevelopment into a separate tropical cyclone from its remnants, an event that was not well anticipated in advance by forecasts. NHC track and intensity forecasts generally performed well given the storm’s small size and short life; intensity forecasts had a tendency early on to overpredict strengthening to hurricane status, which did not occur.