On April 8, the National Oceanic and Atmospheric Administration’s (NOAA) National Centers for Environmental Information (NCEI) announced it will be releasing its once-a-decade update to “climate normals,” on May 4, 2021. This latest update for the Atlantic Hurricane season will also become effective on May 4.
Studies have shown that climate change is also driving changes in the Atlantic Hurricane season. Hotter water on the surface of the ocean, especially in the relatively shallow Gulf of Mexico, helps disturbances strengthen and gain moisture, in turn, leading to more powerful hurricanes.
For the past few years, abnormally warm water in the Atlantic Ocean and the Gulf of Mexico has bred storms that have intensified rapidly into dangerous tropical storms and hurricanes that dumped record-breaking amounts of rain when they made landfall in the U.S., Caribbean, and Central America.
However, Matt Rosencrans, a seasonal hurricane forecaster at NOAA’s Climate Prediction Center explains that NOAA’s new average is based on the recorded storm and hurricane activity over a 30-year period from 1991-2020.
The average number of named tropical storms in a year is now 14, up from an average of 12 before the NOAA update. The average number of full-blown hurricanes is now 7, compared to the old average of 6. These new averages will apply to the 2021 hurricane season, which begins in the Atlantic on June 1. The average for major hurricanes (Category 3, 4 or 5 with wind speeds over 110 miles per hour) remains unchanged at 3.
NOAA also examined the average number of storms forming in the Pacific Ocean and found no change.
Readers may remember that in March this year, meteorologists were considering moving the start date of the Atlantic hurricane season to May 15. Suffice to say it won’t be happening.
Since 20121, many tropical disturbances and storms have formed as early as the last week or so in May. While most of these early-forming systems are benign, at least 20 deaths have occurred from late May storms since 2012, with about $200 million in total damage, and one of these systems was a 60-knot (70 mph) tropical storm at landfall, according to the World Meteorological Organization.
However, moving the start to the hurricane season would need to be brought up in a WMO meeting and the WMO has the final say on whether the start date for the hurricane season is moved. This decision would require an examination regarding the need for, and potential ramifications of, potentially moving the beginning of the hurricane season to May 15.
On Friday, President Biden proposed a $1.4 billion increase in the agency’s budget, up from the current $6.9 billion.
