PORT ST. LUCIE, Fla. — Recalling her youth in St. Catherine Parish, Jamaica, Jhordanne Jones couldn’t think of a storm that caused more destruction than Hurricane Ivan.
In September 2004, the Category 4 behemoth thrust winds of up to 156 miles per hour upon the Caribbean island nation. Jones was in high school.
“We were without water and electricity for a really long time,” she said. “Everything was just down.”
Jones’ hometown had already weathered Category 1 Charley that summer.
“The whole Caribbean was just stagnant,” she said.
Sixteen years later, Jones is part of an American research team that predicts tropical cyclone action in the Atlantic basin. The trio’s 2020 forecast is grim.
Numbers game
The upcoming hurricane season will be more active than usual; more named storms will form than in recent decades, and the United States and Caribbean face increased probabilities of major hurricanes making landfall.
This is the outlook envisaged by the Tropical Meteorology Project at Colorado State University, where 29-year-old Jones is a third-year Ph.D. student in the Department of Atmospheric Science. She assisted research scientist Philip Klotzbach and associate professor Michael Bell in developing the project’s 37th annual forecast, released April 2.
“There is this strong relationship between environment and hurricane,” Jones explained, citing the findings of the late William Gray, a professor emeritus who spearheaded CSU’s first forecast in 1984. “We can use that relationship to create skillful models that can be used to forecast tropical cyclone activity.”
Jones’ team estimates 16 named storms this year, up from the 1981–2010 average of 12.1. That period saw a seasonal average of 6.4 hurricanes, 2.7 of which were major (Category 3 or higher). CSU researchers predict eight hurricanes, four of which will be major, during the June 1–Nov. 30, 2020, season.
“More than enough to keep us busy,” Jones said.
Predicting the occurrence of tropical cyclones is a year-round endeavor, she noted. Klotzbach, Bell and Jones plan to update their forecast monthly beginning in June, then biweekly from August to October, the season’s peak.
“Even after the conclusion of the hurricane season, there are still verifications to do to see how well the model did,” Jones said, “[and] what may have to change for the next year to improve it.”
The Tropical Meteorology Project reflected on nearly four decades of data to develop the latest forecast. While predicting the future is impossible, Jones stressed, the past can divulge much about storms yet to come.
Something in the water
In 2007, hurricanes Dean and Felix walloped the Yucatán Peninsula and Nicaragua, respectively — the first time two Category 5 storms had ever made landfall the same season, according to the National Oceanic and Atmospheric Administration’s Atlantic Oceanographic and Meteorological Laboratory.
Another Category 5 cyclone didn’t form until 2016; Matthew devastated Haiti as a Category 4. The following year brought hurricanes Irma and Maria, which respectively struck the Leeward Islands and Dominica as Category 5 storms.
In 2018, Category 5 Michael became the strongest hurricane to make landfall in the Florida Panhandle, NOAA records show. Most recently, Hurricane Dorian stalled over the Bahamas last summer, reaching 185 miles per hour — far beyond the minimum 157 miles per hour required to attain Category 5 stature.
Tropical cyclones are increasing in intensity. Pioneering geophysicists and meteorologists have identified a likely culprit.
“Climate change changes everything,” said Kerry Emanuel, a professor of atmospheric science at the Massachusetts Institute of Technology. “The bottom line is that globally, we expect to see an increased incidence of the very high-category hurricanes.”
Emanuel and 10 other climate scientists from around the world co-authored an assessment published last fall in the Bulletin of the American Meteorological Society. They linked anthropogenic climate change to an increased global proportion of Category 4 and 5 hurricanes, along with heightened frequency of “Hurricane Harvey-like extreme precipitation events” in the Texas area.
“What a lot of people don’t understand is that as dramatic as hurricanes are as a windstorm, it’s actually the water that kills people — far more people than the wind.”
— Kerry Emanuel, Ph.D., MIT
Hurricanes are labyrinthine natural phenomena, forged and tweaked by a host of factors. But in simple terms, Emanuel explained, tropical cyclones are propelled by the flow of heat from ocean to atmosphere, and sea surface temperatures are rising.
Tom Knutson, a research meteorologist at the NOAA Geophysical Fluid Dynamics Laboratory in Princeton, New Jersey, was lead author of the assessment.
“Our models have been saying for some time that hurricanes are likely to get more intense, on average, with global warming,” Knutson said. “The magnitude of that change [is] something like a 5% increase if you warm global temperatures by 2 degrees Celsius. ... You may get there mid- to late century, depending on how strong the emissions are.”
Emanuel made clear what the team’s findings didn’t reveal: the plight of Category 1 and 2 hurricanes, and whether climate change impacts cyclone frequency.
Part two of the group’s assessment, published in BAMS in March, made a projection Emanuel wants coastal residents to take note of.
Hell or high water
Should 2 degrees Celsius of global warming occur, tropical cyclone precipitation rates could go up by 14%, the researchers concluded, aggravating storm surge.
“What a lot of people don’t understand,” Emanuel cautioned, “is that as dramatic as hurricanes are as a windstorm, it’s actually the water that kills people — far more people than the wind.”
Many who live in hurricane-prone regions are accustomed to riding out historic storms. But no matter how many cyclones they’ve survived in the past, Emanuel stressed, this new era of storms must be heeded.
Jhordanne Jones mirrored Emanuel’s plea. Though she and her Colorado State colleagues forecast a busier-than-normal hurricane season, all it takes is a single storm making landfall for a season to be considered active, she said.
“The best thing to do is to still remain prepared,” Jones said. “If you’ve lived in Florida long enough, you know exactly what the damage can be like.”
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This article was written for Lindsey Leake’s 491.701 Communicating Climate Change course at the Johns Hopkins University Krieger School of Arts and Sciences on April 11, 2020.