Hurricane Polo has rapidly intensified into a Category 5 storm off the southwestern coast of Mexico, emerging as one of the strongest hurricanes ever recorded in the eastern Pacific.
The storm has drawn significant strength from exceptionally warm ocean waters along its path.
The US National Hurricane Center (NHC) reported that Polo had reached maximum sustained winds of 180 mph (285 km/h) by Tuesday afternoon. Measurements collected by a NOAA Hurricane Hunter aircraft also showed an exceptionally low central pressure of 892 millibars.
Polo was expected to bring heavy rainfall, dangerous surf and tropical-storm-force winds to parts of Mexico from late Tuesday into early Wednesday, according to the Miami-based National Hurricane Centre.
The hurricane had been moving east on Monday before forecasters anticipated a “sharp turn” toward the west-northwest or northwest by late Tuesday, an NHC advisory said. While Polo was projected to track close to the western coast of Mexico, forecasts indicated that the system would remain offshore.
The storm’s transformation has been particularly rapid. In approximately 24 hours, Polo strengthened from a tropical storm into a Category 5 hurricane, illustrating a process known as rapid intensification, during which a tropical cyclone’s maximum sustained winds increase substantially over a short period.
At the time of the latest advisory, Polo was located about 215 miles (345 km) south of Zihuatanejo. Forecasters expected the hurricane to remain over the Pacific while moving slowly near Mexico’s southwestern coastline.
By the numbers
Polo’s latest NHC advisory listed maximum sustained winds of 180 mph (285 km/h), while its estimated minimum central pressure stood at 892 mb following measurements by a NOAA Hurricane Hunter aircraft.
The storm had reached Category 5, the highest level on the Saffir-Simpson Hurricane Wind Scale. It had taken roughly 24 hours for Polo to strengthen from a tropical storm into a Category 5 hurricane.
The hurricane was approximately 215 miles (345 km) south of Zihuatanejo. Hurricane-force winds extended outward about 35 miles (55 km) from the centre, while tropical-storm-force winds reached as far as 90 miles (150 km).
Rainfall totals of 3–6 inches (75–150 mm) were forecast for coastal Guerrero and Michoacán, with isolated amounts potentially reaching 8 inches. Coastal areas of Oaxaca, Colima and Jalisco could receive between 2–4 inches (50–100 mm) of rain.
Sea-surface temperatures beneath Polo’s projected path were around 31°C (88°F), providing substantial heat energy that helped support the storm’s rapid strengthening.
Polo’s explosive intensification has been linked to an unusually favourable combination of oceanic and atmospheric conditions.
NHC analysis indicated that sea-surface temperatures beneath the hurricane were above 30.5°C (86.9°F). The storm was also encountering light vertical wind shear and abundant atmospheric moisture. Together, these conditions can allow a hurricane’s circulation to become increasingly organised instead of being disrupted by stronger winds at higher altitudes.
The ocean’s warmth also extends beneath the surface along Polo’s projected route. This is significant because intense hurricanes typically stir the ocean and bring cooler subsurface water toward the surface, potentially reducing the heat available to fuel further strengthening. In Polo’s case, the presence of a deep layer of warm water limits that cooling effect.
There is also a broader climate connection, although forecasters caution against attributing Polo’s development simply to El Niño.
NOAA’s Climate Prediction Center has reported that El Niño is strengthening, with sea-surface temperature anomalies exceeding 3°C in parts of the eastern equatorial Pacific during August. The agency’s latest assessment places the probability of a very strong El Niño developing during the Northern Hemisphere autumn and winter at above 90%.
NOAA’s tropical-hazards outlook has likewise identified El Niño as the dominant influence across the global tropics and has highlighted Polo’s rapid intensification in the eastern Pacific.
However, the conditions directly identified by forecasters as driving Polo’s exceptional strengthening include extremely warm ocean waters, abundant moisture and weak vertical wind shear. As a result, linking the hurricane’s intensity exclusively to El Niño would oversimplify the combination of factors behind its rapid development.
The National Hurricane Center warned that the hurricane is “extremely dangerous” and poses a threat to parts of the states of Guerrero and Michoacán due to elevated flooding.
Hurricane Polo is also reported to bring tropical storm conditions in parts of the coastline, and heavy rainfall could “produce life-threatening flooding and mudslides, especially in areas of steep terrain.”
