Hurricane Season is Back

Palm trees being blown over on the coast

Prepare for an above-average Hurricane Season! That is the message scientists working at Colorado State University’s Tropical Meteorology Project have for residents of South Florida. The research group predicts there will be 17 named storms in the Atlantic Basin this year. It also gives a 45% chance that a major hurricane (category 3-4-5) will hit the east coast of the United States.

The Atlantic has averaged about 12 named storms and six hurricanes a year since 1981 when the center began keeping track. As is the case with all hurricane seasons, it only takes one hurricane-making landfall to make it an active season for everyone. We should prepare the same for every season, regardless of how much activity is predicted.

Last year was the busiest Atlantic hurricane season on record. There were 30 named storms and 13 hurricanes. It was only the second time in history that the National Oceanic and Atmospheric Administration ran out of pre-selected names and was forced to use letters from the Greek alphabet to name storms.

The forecast includes three different models: an extended-range statistical prediction scheme, using 38 years of past data; an analog prediction model; and a statistical/dynamical model based on 40 years of data. All three models call for an active Atlantic hurricane season in 2021.

Factors contributing to the forecast include La Niña conditions in the tropical Pacific. La Niña, which means “little girl” in Spanish, results in colder water off the California coast; the cold water pushes the jet stream northward and leads to warmer conditions in the tropical Atlantic. La Niña conditions are associated with increased storm activity. The tropical Atlantic currently has near-average sea surface temperatures, while most of the subtropical Atlantic is warmer than normal.

Colorado State’s seasonal forecasts were developed by the late Dr. William Gray. He was the lead author on these predictions for over 20 years and continued as a co-author until he died in 2016. In addition to pioneering seasonal Atlantic hurricane prediction, he conducted groundbreaking research in a wide variety of other topics, including hurricane genesis, hurricane structure, and cumulus convection. His investments in both time and energy to these forecasts cannot be acknowledged enough.