Hyperactive tropics of 2020

Almanac

The historic hurricane season of 2005 perked my young meteorological intrigue pushing me harder to learn more about the weather and hurricanes. Little did I know that only 15 years later I would experience another record hurricane season during my professional career. Forecasters knew and predicted correctly that the 2020 hurricane season would be active. The meteorological stage was set. A neutral El Niño Southern Oscillation (ENSO) episode fading to a La Niña episode during summer and fall was key, plus very warm Atlantic Ocean waters. But an even bigger ingredient set this year apart- favorable wind shear.

Wind shear is defined as the difference or change in wind with respect to speed and direction.
When little wind shear is present, a storm system like a hurricane can form uninterrupted by changes in the wind and environment. Add in more shear and the environment becomes less conducive to strengthening storms. During the hurricane season of 2020 low wind shear meant more storms forming and strengthening (rapidly in several cases).

2005 U.S. Department of Commerce, National Weather Service North Atlantic Hurricane Tracking Chart

The season started with Tropical Storm Arthur named on May 16. And after that, it was off to the
races! Only a few lulls in between named storms meant the season was on a record pace, often
exceeding the normal date for the first letter of the named storm (for instance the “M” or “O” storm) by weeks. In fact, the only named storms that did not form ahead of the normal formation date were Arthur, Bertha, and Dolly. The naming convention entered the Greek alphabet list for only the second time in Atlantic hurricane record history. The other year was 2005 when the names ended at Tropical Storm Zeta, which was named on December 30! Tropical Storm Alpha in 2005 was named on October 22, while the fast pace of 2020’s season led to a Tropical Storm Alpha of its own on September 18- over a month ahead of 2005!

2020 U.S. Department of Commerce, National Weather Service North Atlantic Hurricane Tracking Chart

Hurricanes lead to wide areas of damage to homes and businesses along with changing the
landscape in the strongest storm surge cases. The 2020 hurricane season broke the record for
named storms making a United States landfall (at the time of this writing 12 landfalling storms). In addition, the number of named storms exceeded the 2005 record of 28 storms. Truly the 2020
hurricane season has represented the worst of what an active tropical season can bring. While so
many storms can lead to a lot of intrigue, the toll these landfalls take is certainly not something worth repeating. Some estimates at the time of this writing have calculated over $30 billion in damage across the United States as a result of the landfalling storms.

2021 ABC27 Weather Almanac

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