Record-strength El Niño fuels storm’s rapid intensification, scientists say
Hurricane Polo rapidly intensified over 24 hours into one of the most powerful Pacific storms of the season, according to the US National Oceanic and Atmospheric Administration. A NOAA Hurricane Hunter aircraft flew into the storm on Tuesday and measured sustained winds near 180 mph (285 km/h), with stronger gusts. NOAA’s Miami-based National Hurricane Center called the storm “extremely dangerous” and described the intensification as “truly remarkable.”
Polo is the Pacific season’s third Category 5 storm, the highest level on the Saffir–Simpson scale. The slow-moving storm is drawing energy from extremely warm waters linked to the El Niño climate phenomenon, which scientists monitoring ocean temperatures say is now the strongest on record.
Daily sea surface temperatures in a key region of the central-eastern Pacific reached 3.05°C above average on September 19, exceeding the previous record of 3.02°C set during the very strong El Niño of 2015, according to scientists monitoring ocean temperatures. Some longer-term measures of El Niño have not yet hit record levels, but this is likely to change, with the peak not expected until later this year.
The storm is forecast to skirt the coast of southwestern Mexico without making landfall, according to a NOAA warning. As it slowly drifts northwest, Polo is expected to drive torrential rainfall along parts of Mexico’s southwest coast, which could lead to deadly flooding and mudslides, NOAA said. Rainfall totals of up to 6 inches (15 cm) are forecast, with up to 8 inches possible in some areas. Residents have also been warned of large ocean swells and life-threatening surf conditions for the next few days.
“So far, the information we have is that Polo will not make a direct landfall on the coast,” Mexico’s President Claudia Sheinbaum said on Tuesday. Sheinbaum warned residents along the Pacific coast to be vigilant and highlighted the states of Jalisco, Colima, and Michoacán as being at risk.
Data from the Hurricane Hunter aircraft indicated Polo could still strengthen and would likely remain a Category 5 storm for the next few days, because of what NOAA called a “very conducive” environment of extremely warm ocean waters feeding the storm. Warmer ocean waters allow storms to pick up more energy, leading to higher wind speeds.
El Niño is a naturally occurring pattern that happens about every two to seven years and tends to last around a year. Trade winds that typically blow from east to west across the Pacific can weaken or even reverse, allowing warm water to spread east. Heat released from the ocean into the atmosphere can boost global temperatures and drive changes in weather patterns around the world.