Hurricane Polo was downgraded to a category 4 storm on Wednesday morning after reaching category 5 status on Tuesday. The storm, located a few hundred miles south-southeast of Manzanillo, Mexico, produced sustained winds of 180 mph on Tuesday afternoon. While the National Hurricane Center (NHC) expects the storm's center to remain offshore as it moves northwest parallel to the coastline, tropical storm alerts are in effect for the southwestern coast of Mexico.
The storm underwent what meteorologists call extreme rapid intensification, defined as a wind increase of at least 58 mph in 24 hours. Polo's winds increased by 110 mph between Monday and Tuesday morning, growing from a 50 mph tropical storm to a 160 mph category 5 hurricane. The NHC described this rate of intensification as among the fastest on record for the Eastern Pacific, comparable to Hurricane Otis in 2023 and Hurricane Patricia in 2015.
Forecasters attribute the storm's strength to a "super El Niño" and warm ocean temperatures. Data from a National Oceanic and Atmospheric Administration (NOAA) Hurricane Hunter aircraft indicated that the environment remains conducive to further strength. Sea surface temperatures in a key region of the central-eastern Pacific reached 3.05 degrees Celsius above average on September 19, surpassing the previous record set in 2015.
The primary impact for residents in southwestern Mexico involves approximately 2 to 8 inches of rainfall through Thursday. Residents in the states of Guerrero, Michoacán, Oaxaca, Colima, and Jalisco are affected by tropical storm conditions and heavy rain. This volume of rainfall can result in life-threatening flash flooding and mudslides, particularly in areas with steep terrain.
Beyond the immediate rainfall, the storm is generating large ocean swells and dangerous surf conditions expected to last several days. Mexico's President Claudia Sheinbaum has advised residents to remain vigilant, even though the storm is currently projected to stay offshore.
The current El Niño has reached record intensity according to September 19 data. As Polo continues its northwest drift, members of Mexico’s National Guard have been seen patrolling beaches as part of a disaster relief plan. Further updates on the storm's path and intensity are expected through the end of the week.