How rapid intensification spawned two monster hurricanes in one week
By Carolyn Gramling, Science News.
Excerpt: One of the widest hurricanes on record slammed into Florida’s Gulf Coast on September 26 as a powerful Category 4 storm, inundating Florida’s coast with meters-high storm surge and sending tropical storm–force winds as far as 500 kilometers from its eye. ...Just three days earlier, it was a disorganized cluster of thunderstorms off the eastern coast of Mexico’s Yucatán Peninsula. A mere “tropical disturbance,” it was dubbed PTC9 for tracking purposes. ...Within just 60 hours...PTC9 would intensify...from winds less than 35 knots (about 65 kilometers per hour) to hurricane-force winds of at least 100 knots (185 kilometers per hour). It was the fastest predicted spin-up from disturbance to major hurricane in the NHC’s history. ...Rapid intensification is becoming a new normal for hurricanes. NHC defines rapid intensification as when a storm’s maximum sustained winds jump by at least 56 kph (35 miles per hour) in less than a day.... Against a backdrop of ongoing, record-breaking tropical water temperatures, numerous storms in the last few years have met and even surpassed this definition.... In 2023...Atlantic hurricanes Idalia and Lee ratcheted up their intensity by about 58 kph within 24 hours. ...Helene’s fury was fueled by record-hot temperatures in the Gulf of Mexico. ...forecasters were reeling from the sudden intensification of another tropical cyclone, Hurricane John, which made landfall September 23 on Mexico’s southern Pacific coast...two full days earlier than researchers had predicted. ...the storm had spun up into a Category 3 hurricane just a few hours after being classified as a tropical storm....