Seth Borenstein, Associated Press
The Pacific region has recorded a significant number of long-lasting hurricanes, attributed to the current El Niño phenomenon, according to scientists.
Phil Klotzbach, a researcher at Colorado State University, noted, "Since September 20th, when Odalys formed, it's been berserk. This year just everything that forms is just lasting a long time and getting really powerful."
Meteorologists measure hurricane seasons using accumulated cyclone energy (ACE), which accounts for a storm's wind speed and duration. As of Sunday, the area of the Pacific east of the international date line surpassed the previous record set in 2018. The region is currently experiencing Hurricane Simon and is expected to generate another storm soon, Klotzbach stated.
On Tuesday, the Pacific is expected to tie a record for the most consecutive days with a hurricane and likely break it shortly thereafter. Klotzbach remarked, "It feels like almost everything that can spin up does spin up."
Several meteorological factors have contributed to the increased storm activity, primarily the El Niño, which alters high-altitude winds that typically suppress storm formation. Klotzbach explained that the El Niño effect allows storms to thrive in the Pacific, while simultaneously reducing hurricane activity in the Atlantic, where ACE is currently less than 18% of the normal levels for this time of year.
Warm water, which fuels hurricanes, is also a significant factor. Kristen Corbosiero, a professor at the University at Albany, indicated that the equatorial Pacific is several degrees Fahrenheit warmer than usual due to El Niño.
Typically, warm water in the Pacific does not extend as deep as in the Atlantic, which can inhibit subsequent storms. However, this year, storms like Hurricane Rachel have managed to thrive despite passing over areas affected by previous hurricanes.
Additionally, a counterclockwise atmospheric spin over Central America, known as a gyre, has contributed to storm formation, producing both the Atlantic's Isaias and the Pacific's Simon simultaneously.
The last five Pacific hurricanes—Nolo, Odalys, Polo, Rachel, and Simon—have all achieved major hurricane status, with winds of at least 111 mph (178.6 kph). Notably, Polo set a record for duration at Category 5 status, lasting two-and-a-half days.
Klotzbach's analysis of the record-breaking activity considers all storms east of the date line, differing slightly from the National Oceanic and Atmospheric Administration's (NOAA) approach, which divides the area into two regions. While neither NOAA-defined region has reached record ACE levels, together they have.
This year marks the first time both sides of the Pacific have experienced such high activity simultaneously, indicating a widespread reduction in wind shear, warmer waters, and increased moisture.
Currently, a disturbance off the Mexican coast has a 90% chance of developing into Tropical Storm Trudy, which could potentially strengthen further. Corbosiero noted, "This year, because of the El Niño, we do have very favorable conditions. So as long as there's some sort of the seeds either from the gyre or from remnant ends of cold fronts, it seems like this is going to continue for a bit."