How Does this Hurricane Season Compare ?

 

Saffir-Simpson Hurricane Wind Scale (Source: WUSA9)

June and July are two of the quietest months of the Atlantic hurricane season.  There were only three relatively short-lived tropical storms so far this season.  Not since 2017 has the Atlantic come to the end of July without even a single hurricane.  The tropical Atlantic doesn’t usually get busy until the middle of August ahead of the peak of the season in September.  September is when atmospheric and environmental conditions are the most favorable for tropical storm and hurricane development. 

It may seem strange that this season hasn’t had the overall number of named storms by the end of July that recent seasons have had.  Hurricane Barry developed in July 2019, while nine named storms developed through the end of July 2020.  Five named storms developed by this point last season. 

However, in spite of the rapid starts to the previous three hurricane seasons, including the highest overall number of named Atlantic storms in 2020 (30), none of the last three seasons rank among the top 10 based on the seasonal total of Accumulated Cyclone Energy (ACE).  Scientist’s use the ACE Index to gauge how active a hurricane season is based on such factors as storm intensity and duration, as well as the overall number of days with an active tropical storm or hurricane.  One long-lasting, major hurricane could generate more ACE than several weaker and/or short-lived tropical storms.

The 2020 Atlantic hurricane season with an eye-popping total of 30 tropical storms is a good example.  Of those 30 named storms, 11 lasted three days or less and were relatively weak.  That’s not to say a tropical storm or minimal hurricane can’t be destructive or deadly, but the overall number of named storms itself is an artificial measure of how busy a season is.  The 30 tropical storms (that included 14 hurricanes) in 2020 produced a total of 118 days with at least one active tropical storm and a seasonal ACE score of 179.8.

By comparison, the 2017 hurricane season had 17 tropical storms (with 10 hurricanes) for a total of 93 days with at least one active tropical storm. However, since the 2017 hurricane season had 19.25 days with an active, major hurricane (Category 3/+ with sustained winds of 111/+ mph) compared to only 8.75 days in 2020, 2017’s seasonal ACE score was much higher at 224.9.  That made 2017 the Atlantic’s seventh most active season based on its ACE score.  Despite its 30 named storms, 2020 ranked as only the 13^th most active season given its ACE store due to its higher number of weaker storms.

It remains to be seen whether 2022 will end up more like the 2017 or 2020 seasons.  NOAA will issue the early August update to its seasonal hurricane forecast in the next week.