CSU Releases Initial Outlook for 2021 Atlantic Hurricane Season
Today meteorologists and research scientists at Colorado State University (CSU) have released one of the season’s earliest and most well-respected hurricane outlooks.
Early predictions expect this year’s hurricane season to be busier than average. Dr. Phil Klotzbach and the Tropical Meteorology Project at CSU are among the first to issue an outlook for the season. This year they anticipate 17 named storms, 8 of which becoming hurricanes and 4 of those becoming major hurricanes.
Dr. Phil Klotzbach, CSU Research Scientist, explained the reasoning behind the above-average forecast, which includes above average temperatures in the subtropical Atlantic Ocean, and the lack of El Niño conditions expected during the season.
One of the reasons for the above-average seasonal #hurricane forecast from CSU is due to the likely lack of #ElNino this summer/fall. El Nino generally increases vertical wind shear in the Atlantic, tearing apart hurricanes. pic.twitter.com/MBiB8XN9Rg
— Philip Klotzbach (@philklotzbach) April 8, 2021
An El Niño would mean warmer-than-normal water in the central and eastern [tropical] Pacific Ocean. That tends to create more wind shear to tear apart hurricanes in the Atlantic. Because El Niño is not expected to limit development, more hurricanes may form.
Above average temperatures are already present in the sub-tropical Atlantic Ocean. Warmer sea-surface temperatures contribute to tropical cyclone formation and help to fuel the storms.
In addition to the forecast for an above average number of storms, CSU also predicts an above average season in ACE (Accumulated Cyclone Energy), Hurricane Days, and Major Hurricane Days.
The CSU forecast probability of at least one landfall for the entire U.S. coastline is 69%, the average for a typical season is 51%.
There are five previous hurricane seasons that compare to this [anticipated] season, according to the CSU report. Those [analog] years are 1996, 2001, 2008, 2011 and 2017.
You can read the report in its entirety here.
New this year, as of Friday April 9th, is the updated average number of tropical cyclones and hurricanes. During the 1981 – 2010 climate period, there were 12 named storms in an average year, 6 hurricanes, and 3 major hurricanes. With the new 1991 – 2020 data set, the Atlantic now averages 14 named storms, 7 hurricanes, and still averages 3 major hurricanes.