Hurricane Polo has intensified into one of the strongest hurricanes ever recorded in the western hemisphere, churning in the eastern Pacific Ocean.

As of Tuesday night, Polo sustained winds of 165 miles per hour, according to the National Hurricane Center (NHC). The storm's winds had reached 180 miles per hour earlier that day, matching some of the most powerful storms globally this year.

Forecasters expect Polo to remain a major hurricane throughout the week, maintaining Category 5 strength, which signifies sustained winds capable of catastrophic damage. Such storms are rare, requiring a specific confluence of warm ocean waters, low wind shear, and high atmospheric moisture, though they have become more common in recent years.

Polo's rapid intensification has been particularly noteworthy. Its maximum sustained winds surged from 50 miles per hour on Monday morning to 160 miles per hour by Tuesday morning, an increase of 110 miles per hour in 24 hours. This rate of strengthening far exceeds the threshold for "extreme rapid intensification."

The storm's development echoes that of Hurricane Otis in 2023, which also underwent rapid intensification before making landfall near Acapulco, Mexico, causing catastrophic damage.

Tropical storm warnings have been issued along Mexico's southwestern coast. Heavy rainfall of 3 to 6 inches is expected across coastal Guerrero and Michoacán through Thursday, with isolated totals of up to 8 inches. Parts of Oaxaca, Colima, and Jalisco could receive 2 to 4 inches. This rainfall poses a risk of severe flooding and mudslides, particularly in steep terrain, reminiscent of the devastating flash flooding and mudslides caused by Hurricane John in September 2024.

In addition to heavy rains, Polo is generating life-threatening surf and rip currents along the southwestern Mexican coast. Coastal areas in Baja California Sur are expected to experience deteriorating conditions by Friday, with the hurricane potentially nearing the peninsula's southern tip over the weekend. The U.S. Embassy in Mexico has alerted residents to the hazardous conditions.

NWS San Diego has indicated that parts of Southern California could experience peripheral impacts, including possible coastal flooding and erosion.

Polo's rapid strengthening is attributed to its passage over warm ocean waters, which provide heat and moisture, and areas of low wind shear, which allow its thunderstorms to remain organized.

This intensification occurs during a period of a "super" El Niño. El Niño typically favors hurricane activity in the eastern and central Pacific by increasing ocean temperatures and creating atmospheric conditions conducive to storm development.

This year, the strong El Niño has contributed to an increased frequency and intensity of hurricanes in the eastern and central Pacific. Polo is the third Category 5 hurricane in the eastern Pacific since May 15, tying a seasonal record. With El Niño forecast to strengthen further, conditions are expected to continue favoring hurricane activity in the region.

Conversely, the same El Niño has suppressed hurricane activity in the Atlantic Ocean, leading to the latest start to hurricane activity in the satellite era. Increased wind shear in the Atlantic disrupts the formation of tropical storms.

However, El Niño does not preclude Atlantic hurricanes entirely. Climate change can also contribute to more intense storms, even in seasons with fewer formations.