Hurricane Polo roared back to Category 5 and shut down six Mexican ports

Hurricane Polo tore back into Category 5 strength off Mexico’s Pacific coast on September 23, regaining maximum sustained winds of 160 mph and a central pressure of 925 millibars after a brief weakening spell. The National Hurricane Center’s confirmation of the re-intensification pushed Mexican port authorities to close six ports to some or all vessel traffic, even though Polo’s center held roughly 145 miles offshore the entire time. Guerrero and Michoacán also shut schools along the coast as forecasters warned of life-threatening surf and flooding rain well away from the eye itself.

An eyewall replacement cycle gives way to a second Category 5 peak

The storm had first reached the top of the Saffir-Simpson scale three days earlier, then weakened before roaring back, making September 23 the second time in a single week that Mexican forecasters had to plan around a Category 5 hurricane sitting just off the coast rather than a weaker system passing well out to sea.

An advisory the National Hurricane Center issued at 6:40 p.m. CST on September 23 declared that Polo “has quickly strengthened into a Category 5 hurricane,” with maximum sustained winds of 160 mph and a minimum central pressure of 925 millibars. The advisory placed the storm about 145 miles southwest of Zihuatanejo, Mexico, creeping northwest at just 6 mph. It marked the second time in three days that Polo reached the top of the Saffir-Simpson scale — the agency first declared Polo a Category 5 hurricane at noon on September 22, when it carried 165 mph winds and a 920-millibar pressure reading and sat farther south, near 14.6°N, 101.6°W.

Between those two peaks, Polo dropped to Category 4 after an eyewall replacement cycle, the process in which a storm’s inner eyewall collapses and a wider one forms around it, briefly interrupting the core before the storm can reintensify. At its first peak, Polo’s winds of 180 mph tied 2009’s Hurricane Rick for the third-highest ever recorded in the Eastern Pacific, and its pressure drop to 892 millibars ranked second only to 2015’s Hurricane Patricia, which bottomed out at 872 millibars with 215 mph winds. Meteorologist Andy Hazelton wrote that the pattern “almost looks like an eyewall replacement cycle,” adding that “it’s a bit early in the process” for a storm still this early in its life cycle.

National Hurricane Center senior specialist Eric Blake said Polo’s intensification stood out among the storms he has tracked, noting that “one rapid intensification index was showing percentages as high as [he had] ever seen.” The storm’s hurricane-force winds extended only about 35 miles from its center, a compact structure that let it strengthen quickly even as it stayed offshore.

Six ports and dozens of schools close along the coast

Mexican authorities closed six ports as Polo lingered offshore, according to reporting on the closures along Mexico’s Pacific coast. Acapulco and Zihuatanejo were closed to all vessel traffic, while Puerto Marqués, Lázaro Cárdenas, Manzanillo and Puerto Escondido were closed to small craft only. The restrictions stretched across roughly 500 miles of coastline even though Polo’s eye never came ashore, underscoring how far a compact but intense storm’s wind field and swell can reach.

Guerrero suspended classes across its Costa Grande, Acapulco and Costa Chica regions beginning September 22, and Michoacán closed schools in seven coastal municipalities, including the port city of Lázaro Cárdenas, on September 22 and 23. Jalisco and Colima issued precautionary closures of their own as Polo’s outer rain bands reached the coast, even with the storm’s center staying dozens of miles out to sea throughout the week.

Life-threatening surf and flooding rain even with the core offshore

Forecasters warned of 3 to 6 inches of rain across Guerrero and Michoacán, with isolated totals as high as 8 inches, raising the risk of flooding and mudslides in steep coastal terrain. Life-threatening surf and rip currents were expected along the southwestern Mexican coast, prompting a tropical storm warning that stretched from Tecpan de Galeana to Manzanillo and a tropical storm watch reaching into Jalisco near Playa Perula.

The hazards arrived even though Polo’s center stayed well offshore during both Category 5 peaks, a reminder that a storm does not need to make landfall to force port shutdowns and school closures along dozens of miles of coastline. Emergency officials in Guerrero and Michoacán treated the rainfall threat as comparable to a direct hit, given the region’s steep terrain and history of deadly mudslides during past Pacific hurricane seasons.

A track that bends toward Baja California by the weekend

Forecasters expected Polo to weaken to a Category 2 storm by the time it passed roughly 125 kilometers west-southwest of Cabo San Lucas on September 28, tracking farther offshore as a building ridge steered it northward along the Pacific side of the Baja California peninsula. The storm was projected to turn west-northwest through September 25 before bending northwest and eventually north as it reached the ridge’s western edge over the following weekend.

Polo was the third Category 5 hurricane of the Eastern Pacific season, following an unusually active stretch of rapid intensification events that has kept National Hurricane Center forecasters watching the basin closely. Whether the storm’s two swings through Category 5 strength in three days signal a third remains an open question forecasters said they could not rule out before Polo reaches the ridge and begins its turn toward Baja California.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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