Hurricane Polo has rapidly intensified into one of the most powerful Pacific storms in decades, threatening Mexico's south-western coast with dangerous flooding, mudslides, and life-threatening surf conditions.

A Hurricane Hunter aircraft operated by the US National Oceanic and Atmospheric Administration (NOAA) flew into the storm on Tuesday and recorded sustained wind speeds of between 165 mph (265 kph) and 180 mph (285 kph), with stronger gusts. The National Hurricane Center (NHC) in Miami described the storm as "extremely dangerous" and said its intensification over 24 hours was "truly remarkable."

Polo is the third Category 5 hurricane of the 2026 Pacific season, following Genevieve and Lowell earlier this year. Category 5 is the highest level on the Saffir-Simpson scale, reflecting maximum sustained winds exceeding 157 mph (253 kph). It is also the 18th named storm and seventh hurricane of the season, which runs from 15 May to 30 November.

The storm was centered approximately 210 to 215 miles (338 to 346 kilometers) south of Zihuatanejo, Mexico, and was nearly stationary over the Pacific Ocean as of Tuesday. Forecasters said Polo was expected to begin a slow but sharp turn north-west during the night, then continue in a generally west-north-westward direction over the following days.

Mexico is not expected to suffer a direct landfall. "So far, the information we have is that (Polo) will not make a direct landfall on the coast," Mexican President Claudia Sheinbaum said on Tuesday, though she urged residents along the Pacific coast to remain vigilant. Sheinbaum highlighted the states of Jalisco, Colima, and Michoacan as being at particular risk.

Despite the storm remaining offshore, hurricane-force winds were reported up to 40 miles (65 kilometers) from the storm's center, with tropical storm-force winds extending up to 105 miles (169 kilometers) away. The NHC warned that tropical storm conditions were expected along the Pacific coast in the states of Guerrero, Michoacan, and Colima.

Rainfall totals of 3 to 6 inches (8 to 15 centimeters) were forecast for Guerrero and Michoacan, with up to 8 inches (20 centimeters) possible in some areas. Residents were also warned of large ocean swells, dangerous rip currents, and life-threatening surf conditions expected to persist for several days.

The US Embassy in Mexico issued a weather alert instructing American citizens to avoid water and beaches and to follow guidance from Mexican authorities. "Even if the storm does not make direct landfall, heavy rain may produce life-threatening flooding and mudslides. Hazardous ocean conditions — intensified by storms — may result in deadly rip currents and rogue waves," the embassy said in a statement.

Mexican authorities temporarily suspended classes in a number of areas on Tuesday. The country's navy shut down ports in the states of Guerrero and Michoacan and warned civilians and fishermen to take precautions.

In the coastal city of Lazaro Cardenas in Michoacan, strong waves were already reaching the shoreline. Local restaurant owner Concepcion Lopez Villegas was preparing her business for what may come. "We're worried and trying to protect our businesses," she said. "And of course, we're sad because it's our heritage, our legacy that from one moment to another could be destroyed."

Scientists attributed Polo's explosive intensification to the El Nino climate phenomenon, which has produced exceptionally warm ocean waters in the Pacific. "There are all the ingredients that hurricanes need to get really strong really fast," said Philip Klotzbach, a research scientist in the Department of Atmospheric Science at Colorado State University.

On Monday, Polo had been only a tropical storm with winds below 74 mph (120 kph). Its rapid growth has been linked to what forecasters described as a "very conducive" environment of extremely warm ocean waters. The 2026 El Nino has been described as one of the strongest on record, with one assessment noting it set a record as the most extreme on record as of Monday.

"This is one of the strongest storms ever in the (Pacific) Basin," said Kristen L. Corbosiero, professor at the University at Albany's Department of Atmospheric and Environmental Sciences. NHC data shows Polo has reached speeds comparable to only a few hurricanes to form in the region in recent decades, primarily Hurricane Patricia, which reached 215 mph (346 kph) in 2015.

In contrast, the Atlantic basin has remained unusually quiet. No Atlantic hurricanes have formed so far this year, setting a record for the longest start to a season without one. It is the first time in 112 years that no Atlantic hurricanes had formed by 21 September. The year 2026 could join 1907 and 1914 as the only years on record without a single Atlantic hurricane. Meteorologists say El Nino is suppressing Atlantic storm development through increased wind shear while simultaneously fueling heightened activity in the Pacific.