May usually is the month for flowers that follow April showers. But it’s also become a time for early-arriving tropical storms and hurricanes.
Since 2015, at least one named storm has formed before June 1, the official start of the Atlantic hurricane season which runs through Nov. 30. To monitor the increase in preseason storms, the National Hurricane Center, for the first time ever, will start issuing twice-daily tropical weather forecasts starting May 15.
Following a record-breaking 2020 Atlantic hurricane season, the World Meteorological Organization (WMO) announced in February that the National Hurricane Center would “examine the need for potentially moving the beginning of hurricane season to May 15.” The hurricane center eventually decided against changing this season’s start date but instead announced plans for May forecasts.
In May 2020, two tropical storms brought rain and gusty winds to the Carolinas. Tropical Storm Arthur formed May 16 and soaked eastern North Carolina. Tropical Storm Bertha formed on May 27 and made landfall on the South Carolina coast.
Some 40 storms have developed in the Atlantic Basin before June 1 between 1851 and 2020, according to the National Oceanic and Atmospheric Association (NOAA).
The most recent May hurricane was Alma, which intensified to peak winds of 80 mph on May 20, 1970 and affected Jamaica and the Cayman Islands.
This year’s Atlantic hurricane season is expected to be more active than usual, according to the Colorado State University Tropical Meteorology Project. Its forecast calls for 17 named storms, eight hurricanes and four major hurricanes. A major hurricane is rated Category 3 or higher (115-plus-mph winds) on the Saffir-Simpson Hurricane Wind Scale.
The CSU team bases its forecasts on models that use 40 years of hurricane seasons and evaluate conditions including: Atlantic sea surface temperatures, sea level pressures, vertical wind shear levels, El Niño (warming of waters in the central and eastern tropical Pacific), and other factors.
So far, the 2021 hurricane season is looking a lot like above-average seasons in 1996, 2001, 2008, 2011 and 2017.
“All of our analog seasons had above-average Atlantic hurricane activity, with 1996 and 2017 being extremely active seasons,” Phil Klotzbach, a research scientist in the Department of Atmospheric Science and lead author of the report, said in a statement.
2021 hurricane names
Additional storms will not use the Greek alphabet this season to avoid any confusion, the World Meteorological Organization announced.
In case of another busy hurricane season, these names will be used: