Hurricane Polo is a Category 4 monster, a 'rare show of force' - USA Today

A monster of a hurricane that set records when it exploded in strength and intensity in the eastern Pacific Ocean is threatening parts of Mexico's coast with flooding rain, winds and high surf.

Hurricane Polo, now a Category 4 storm with maximum sustained winds of 155 mph on Sept. 24, became the second-strongest hurricane in the Pacific basin, forecasters said. Its wind speeds went from 85 mph to a peak of 180 mph in just 22 hours earlier in the week.

The "extremely powerful" storm is expected to remain a major hurricane for the next few days, the National Hurricane Center said on Sept. 24.

As of midday Thursday, Polo was about 195 miles west-southwest of Zihuatanejo, Mexico, and was moving west-northwest at 10 mph. It's expected to make a turn toward the west-northwest later on Sept. 24 and Sept. 25. Its core will likely remain offshore of southwestern Mexico on Sept. 24 before moving farther out to sea, the hurricane center said. Tropical storm conditions are impacting the coast of Mexico, and a tropical storm warning is in place from Tecpan de Galeana to Manzanillo; a tropical storm watch is in effect from Manzanillo to Playa Perula.

"Polo will bring flooding rain to the Mexican states of Jalisco, Colima, Guerrero, Oaxaca and Michoacán through the end of the week," AccuWeather meteorologist Alex Duffus said.

Polo is not to be confused with Tropical Storm Nolo, expected to become a hurricane in the central north Pacific Ocean later on Sept. 24 and threatening Hawaii with extreme rain. The similar names come from two different lists produced by the World Meteorological Organization.

Hurricane Polo strengthened from a disorganized tropical depression to a Category 5 hurricane in a remarkable 42 hours, the fastest of any system on record in the Western Hemisphere, said Michael Lowry, a hurricane specialist with WPLG-TV in Miami.

Its lowest central pressure – 892 millibars – was the second-lowest in a hurricane on record, Phil Klotzbach, a senior research scientist with the Department of Atmospheric Science at Colorado State University, posted on X. The lowest – 872 millibars – occurred in Hurricane Patricia in 2015. Typically, the lower the pressure, the stronger the storm.

Polo's winds peaked at 180 mph on Tuesday, Lowry wrote in a Substack blog post Wednesday. Polo tied with Hurricane Rick in 2009 for the third-strongest eastern Pacific hurricane on record, measured by maximum sustained winds.

The flight-level temperature reading inside Polo’s eye on Tuesday “tied Hurricane Rita’s in 2005 for the warmest on record, surpassing even some of the most intense western Pacific Super Typhoons ever directly observed like Megi in 2010,” Lowry wrote, crediting Derrick Herndon, a hurricane researcher at the University of Wisconsin-Madison’s Cooperative Institute for Meteorological Satellite Studies.

“Simply put, the amount of latent heat being released inside the core of Polo from the intense ring of thunderstorms surrounding its eye (the notorious eyewall) was exceptional, a rare show of force from Mother Nature when everything aligns to form one of the most powerful storms on Earth,” Lowry wrote.

Tropical storm conditions will persist throughout Sept. 24 in the tropical storm warning area and are expected to spread within the watch area later in the day.

Polo is expected to dump 4 to 6 inches, with isolated totals of up to 8 inches, across coastal parts of the Mexican state of Guerrero, which could lead to flooding and mudslides, especially in steep terrain, forecasters said. In coastal parts of Michoacán, Colima and Jalisco, 2 to 4 inches could fall.

Dangerous surf conditions are also expected for the next couple of days.

"Swells will spread northward along the coast of west-central Mexico and toward Baja California Sur on Friday and into the weekend. These swells are likely to cause life-threatening surf, rip currents, and coastal flooding," the hurricane center said.

According to AccuWeather, Polo will quickly lose wind intensity as it moves inland on Monday and Tuesday, where it could bring soaking rain and moisture into northwestern Mexico and the U.S.

"If Polo takes the track we currently expect, some rain and moisture can be pulled into Texas, but how much will be influenced by the storm’s ability to cross the Sierra Madre mountains,” said AccuWeather hurricane expert Nicholas Arman in an email to USA TODAY. “The Sierra Madres often act like a cheese grater to an organized system, shredding it apart and preventing any organized tropical feature from staying together.”

“This is textbook El Niño impacts, where the strong tropical development in the Pacific ultimately pushes moisture into the southwestern U.S.,” Arman added. “This area around Texas, New Mexico and Arizona has been quite wet recently with heavy monsoonal rain the past few weeks. These soaked areas will be at an enhanced risk of flooding.”