Come April, tropical meteorologists across the world look to the Colorado State University department of atmospheric science for its annual extended range forecasts on Atlantic hurricane season activity.
According to this year’s April 2 report titled “Extended Range Forecast of Atlantic Seasonal Hurricane Activity and Landfall Strike Probability for 2020,” CSU researchers Philip Klotzbach, Michael Bell and Jhordanne Jones predict higher than average hurricane activity and landfall strike probability.
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“Current warm neutral (El Niño–Southern Oscillation) conditions appear likely to transition to cool neutral ENSO or potentially even weak La Niña conditions by this summer/fall,” reads the opening paragraph of the report. “Sea surface temperatures averaged across the tropical Atlantic are somewhat above normal. … We anticipate an above-average probability for major hurricanes making landfall along the continental United States coastline and in the Caribbean.”
The report forecasts 16 named storms, eight hurricanes and four major hurricanes, with 80 named storm days, 35 hurricane days and nine major hurricane days. Additionally, it estimates that the probability of U.S. major hurricane landfall is 130% of the long-period average.
Jones, the graduate research assistant on the report and a Ph.D. student in atmospheric science and tropical meteorology, said the April report takes about a month to prepare, but observations about the environment included in the report start the year before.
“Since hurricane activity is so variable and it’s so dependent on the environment, it very likely has some connection to hurricane activity in the previous year,” Jones said. “The CSU forecast looks at not only the current environmental situation or condition; it also takes into account what the environmental condition was like in the years prior to the season.”
Jones conducts research based on the forecast as part of her dissertation.
“I eventually look at ways to improve the forecast, what dynamical or environmental signals we’re missing,” Jones said. “I tend to use a lot of pre-analysis data, which is essentially a combination of observations of hurricanes and the large-scale environment.”
When you read the seasonal outlook, bear in mind that there will be variability. The numbers will probably not match up to what we observe, but it is there to make sure that you are aware and you are prepared for anything that comes.” -Jhordanne Jones, CSU Ph.D. student and graduate research assistant
CSU has released 36 such reports since 1984, when professor emeritus William Gray initiated the seasonal forecasts.
“People around the world have become used to us producing hurricane predictions, which means that we have to keep up with the latest research,” Jones said.
Kate Musgrave, a researcher for the Cooperative Institute for Research in the Atmosphere, wrote in an email to The Collegian that her research focuses on the life cycle of individual hurricanes, understanding how a storm will change in the next few hours to several days and then turning that understanding into better models and guidance for operational hurricane forecasters.
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“These reports can give us a general idea of how active a season we may be facing in the upcoming year, which can be particularly useful to those who work with risk management, like those in insurance and economics,” Musgrave wrote. “It can also be useful to those of us who are working on the shorter-term forecasts, like trying to predict where and how strong a hurricane will be in five days, because the factors they study for the seasonal report can be just as important to how an individual hurricane evolves as it is to how the season evolves.”
According to the extended range report, it is impossible to precisely predict the season’s hurricane activity so early in April. However, CSU’s reports have had modest long-term skill when evaluated in hindcast mode.
“We would never issue a seasonal hurricane forecast unless we had models developed over a long hindcast period which showed skill,” reads the report. “We also now include probabilities of exceedance to provide a visualization of the uncertainty associated with these predictions.”
New forecast reports will be published on June 4, July 7 and Aug. 6.
Jones said these reports take into consideration the forecasts and data for the month and allow them to adjust the forecast outlooks for the rest of the hurricane season.
“When you read the seasonal outlook, bear in mind that there will be variability; the numbers will probably not match up to what we observe, but it is there to make sure that you are aware and you are prepared for anything that comes,” Jones said. “It only takes one storm to make it a really bad year for people and to make it an active season for a region.”
Serena Bettis can be reached at news@collegian.com or on Twitter @serenaroseb.
