Hurricane Polo undergoes extreme rapid intensification as El Niño warms the Pacific
While the Atlantic has been quiet this year, off Mexico's Pacific coast, Hurricane Polo underwent a historic intensification, growing from a 50 mile-per-hour tropical storm to a 160 mile-per-hour Category 5 monster in just 24 hours.
That jump of 110 miles per hour in one day is one of the fastest intensification rates ever recorded in the Eastern Pacific. It falls only second to Hurricane Patricia, whose winds jumped 120 miles per hour in a day in 2015.
Polo is also the second-most "intense" Pacific hurricane by pressure behind Patricia, with central pressures dropping to 892 mbar and 872 mbar, respectively. Polo's winds topped out at 180 miles per hour late Tuesday, tying Hurricane Rick as the third-strongest Pacific storm by wind speeds, behind Linda and Patricia.
These records are exclusive to the Eastern Pacific, where tropical cyclones are known as hurricanes. West of the International Date Line, cyclones are called typhoons, and they can regularly grow larger and more intense than their eastern counterparts.
Forecasters point to a "super" El Niño fueling the Pacific this year, resulting in unusually warm ocean water, low wind shear, and high moisture, all the ingredients a hurricane needs to explode in strength almost overnight.
According to Climate Central's Ocean Climate Shift Index, the above-average sea surface temperatures fueling Polo in the Pacific were 100 to 200 times more likely due to climate change. These numbers are so big because the ocean doesn't vary much day to day, making it much easier to see the influence of climate change.
El Niño will continue to strengthen through late fall, which could continue the active trend in the Pacific. The Atlantic should likewise stay quieter due to the presence of more wind shear in El Niño years. There have been no recorded hurricanes in the Atlantic so far this year, the quietest start to the season since satellite measurements began.
Polo has since eased slightly to a strong Category 4, and forecasters expect it to stay offshore, parallel to the Mexican coast, through the end of the week. But its hurricane-force winds still stretch dozens of miles from the center, and coastal Guerrero and Michoacán could see up to a foot of rain, raising the threat of flooding and mudslides.
