Hurricane Polo regains Category 5 with 180 mph winds off Mexico

Hurricane Polo regained Category 5 status off Mexico's southwestern coast with maximum sustained winds of 180 mph on Friday, well above the 157 mph needed for the category, the National Hurricane Center said. Polo's core sat about 320 miles southwest of Cabo Corrientes in Jalisco, heading west at 10 mph, with the storm expected to start slowly weakening by the weekend.cbsnews.com

Polo's return to Category 5 matters because it is now the second-strongest hurricane on record in the Eastern Pacific by central pressure, behind only 2015's Hurricane Patricia, and its winds tied 2009's Hurricane Rick as third-strongest for the region. The storm has already forced evacuations, shelter openings and nearly 19,800 personnel deployments across Mexico's Pacific states without its eye ever making landfall.

How Polo regained Category 5 strength

Polo's intensification has been erratic. It reached Category 5, weakened to Category 4, then intensified again on the afternoon and evening of Wednesday, September 23. At 6:40 p.m. Wednesday the National Hurricane Center confirmed it had regained Category 5 status with winds of 260 km/h. At midnight on Thursday, September 24, the center classified it as Category 5 with winds of 260 km/h and minimum central pressure of 923 millibars.

Earlier, during the early hours of Wednesday, the hurricane reached sustained winds of 270 km/h and a minimum pressure of 905 millibars while remaining nearly stationary off southwestern Mexico. Its center was approximately 205 kilometers southwest of Zihuatanejo, Guerrero, and 320 kilometers south-southeast of Manzanillo, Colima, moving northwest at about 11 km/h. The center maintained a tropical storm warning from Tecpan de Galeana to Manzanillo.

Polo underwent extreme rapid intensification between Monday and Tuesday, with winds climbing from 45 mph early Monday morning to 150 mph around the same time the following day. By September 22, maximum sustained wind speed had risen by 90 knots (104 miles per hour) within 24 hours, reaching Category 5 strength. The National Hurricane Center called the intensification "truly remarkable."

Why the ocean fuelled the storm

The mechanism combined weak wind shear, high moisture, warmer ocean temperatures and high atmospheric instability, an environment Gary Partyka, an atmospheric scientist at NASA's Goddard Space Flight Center, called "near perfect" for strengthening. Sea surface temperatures reached 32 degrees Celsius (90 degrees Fahrenheit), 2 to 3 degrees warmer than usual for September 23, and warm water at depth limited the cool water wake that normally slows a storm.

Kristen Corbosiero, an atmospheric scientist at the State University of New York at Albany, said weak winds above the system and good outflow at the top also contributed to the rapid intensification. Both she and Partyka cautioned against attributing Polo's intensification directly to El Niño, noting past rapid intensification during La Niña and neutral conditions, including Hurricane Otis in 2023 and Patricia in 2015.

Where the damage has concentrated

Damage has concentrated in coastal Michoacán. In Playa Azul, in the municipality of Lázaro Cárdenas, sea water entered streets near the shoreline and swept away furniture and structures belonging to beachfront businesses. Business owners built sandbag barriers, but some failed to hold. Armed Forces personnel joined the cleanup, and municipal authorities began preventive evacuations of families living along Playa Azul's beachfront on Thursday.mx.ibtimes.com

Nearly 19,800 security, military and emergency-response personnel were mobilized across Guerrero, Michoacán, Colima, Jalisco and Nayarit. Michoacán was forecast to receive 75 to 150 millimeters of intense rain, sustained winds of 60 to 80 km/h, gusts of 90 to 110 km/h and waves reaching six to eight meters. Shelters in Lázaro Cárdenas were inspected for water quality and sanitation by the Michoacán Health Secretariat.

Polo could produce 4 to 8 inches of rain, and up to a possible 10 inches, across parts of Baja California Sur, the hurricane center said, warning the rain "may produce life-threatening flooding and mudslides, especially in areas of steep terrain." Swells were expected to spread north along the west-central coast and the Baja California peninsula through the weekend.

Classes were suspended at schools across Acapulco in Guerrero, and Michoacán authorities canceled classes through Friday in coastal municipalities, urging residents not to leave home unless essential. Mexican leaders ordered evacuations, opened shelters and deployed military troops. A Unified Command Post with the Navy and Civil Protection was established in Lázaro Cárdenas to track Polo's path.

The State Department, citing forecast models, said Polo is expected to weaken to a Category 1 storm before making landfall in northern Baja California Sur on Monday, then continue northeast into southern Sonora. As of September 24, accumulated cyclone energy in the eastern Pacific was nearly twice the norm, according to data from Colorado State University.