A look back at the extraordinary 2020 Atlantic Hurricane Season.

 

The hyperactive 2020 Atlantic hurricane season officially ended Monday, November 30th. The season set or tied several records.

In an average hurricane season, which runs from June 1st through November 30th, we typically see around 12 named storms, six hurricanes, and three major hurricanes. This year we more than doubled that number.

The season started early, on May 14 with the christening of Arthur, more than two weeks before the season officially began. Tropical Storm Bertha became the second tropical storm, when she was named on May 27^th. This is only the sixth time since records have been kept in the 1700s that two tropical storm or greater storms have formed before the start.

The season had 30 named storms in the Atlantic through November 30^th, surpassing the 28 from 2005.

The Season consisted of: Arthur, Bertha, Cristobal, Dolly, Edouard, Fay, Gonzalo, Hanna, Isaias, Josephine, Kyle, Laura, Marco, Nana, Omar, Paulette, Rene, Sally, Teddy, Vicky, Wilfred, Alpha, Beta, Gamma, Delta, Epsilon, Zeta, Eta, Theta, and Iota.

 Nearly all of those named storms set records for being the earliest of their letter to ever form.

13 became hurricanes with top winds of 74 miles per hour or more. That was the second most ever, behind only 2005 when 15 hurricanes formed.

6 of the hurricanes were major with top winds of 111 miles per hour or higher. Those hurricanes were Laura, Teddy, Delta, Epsilon, Eta and Iota. The only known season with more major hurricanes was 2005 which had a total of seven.

There was a total of 12 U.S landfall in 2020; the greatest number of landfalling named storms in a single season on the CONUS. Five of those storms came ashore in Louisiana, this set another record for the most landfalling storms in the state for a single season.

The 2020 hurricane season saw 6 hurricanes make a U.S landfall, this ties 2020 with 1886 and 1985.

July, saw 5 tropical cyclones in the Atlantic. That means the 2020 season tied with 2005 for the most Tropical cyclones in the Atlantic for the month of July in the historic record.

Most named Storm Formations during September on Record, September had 10 named storm formations. On September 18^th 3 Storms Formed in just in just six hours.  The 18^th ended up tying a record for most storms formed on a single day.

The Atlantic had five active tropical cyclones for a brief time on Sept. 14, including Paulette, Rene, Sally, Teddy and Tropical Depression Twenty-One. While that's not a record, it's only the second time the Atlantic basin has had five or more tropical cyclones at one time.

For the first time in recorded history, two major hurricanes formed in the month of November.

November also saw 20 named storm days, this ties 1932 for the most storm days in the month of November.

Iota became the latest hurricane to reach Category 5 status, in the recorded history of the Atlantic Basin. The only other November category 5 occurred in 1932, and that one formed in the first week of the month.

Rapid intensifying tropical cyclones was one of 2020 Atlantic Season hallmarks. 9 of the season's 13 hurricanes underwent rapid intensification, matching a record set by the 1995 and 2010 seasons. In fact 3 of them underwent 36 hour rapid intensification of at least 100 mph; those were Delta, Eta, and Lota, this feat has only been done by only 8 other storms going back to 1851. 

Rapid intensification is defined as a storm undergoing a maximum wind increase of at least 29 mph within a 24-hour period.

 

Here is a link to part 3 of my 2020 Atlantic Season Hurricane Outlook.  I think it was dead on based on all metrics.   Part 3.

 

Why was 2020 so active?

We had the quickly developing La Nina in the equatorial Pacific. This coupled with the warm Sea Surface Temperatures due to the Atlantic Multi Decadal Oscillation (AMO) being in its warm phase, as well as a strong West African monsoon. All of this caused weaker vertical wind shear and a favorable upper wind pattern over the Atlantic.  The atmospheric and oceanic conditions over the equatorial Atlantic, Caribbean, and Gulf of Mexico made what happened possible.

 

We had a record number of named storms, but was 2020 the most intense season on record?

 Some climate scientists and many climate change activists say because the earth is warming hurricanes will become stronger than they were in the past. While in theory a warming planet, with warm sea surface temperatures would increase both the number and intensity of tropical cyclones. In reality there is no definitive proof that is really the case.  2020 is a perfect reminder of that.

To see that we have to look at the Atlantic Accumulated Cyclone Energy (ACE) Index for 2020. ACE is a measure of the intensity and longevity of all the named storms during the entire year. The index is all about wind energy.

An ACE Value of 104 to 106 is considered an average season in the Atlantic Basin. Data from the Department of Atmospheric Science at Colorado State University, shows that the ACE so far this year in the North Atlantic is 179.8.  That is well above average.

But the hurricane season that saw the highest ACE value was 1932 with an ACE of 259 to 260. 2005 ranks 2^nd with a value of 250 to 251. So, while 2020 saw the highest number of total named storms of any season on record in the Atlantic. The ACE value shows this year is nowhere near the top of the list. In fact, 2020 ranks 13^th on the list of highest ACE years in the Atlantic. That list goes back to 1851.

So, while 2020 was a very active season, it ranks much less intense than several other years. It was very active but not super extreme. Why is that the case?

Technology and naming questionable disturbances.

Tropical Cyclones in the Atlantic have been observed and recorded for centuries. At first most reports were land based. But as shipping active increased, ship reports became very important for warning people along the coast.  But unless a hurricane came ashore, or a ship happened to encounter one. Many most likely went unnoticed. Technology advances such as the Telegraph, meant many more people could be warned in advance. When Aircraft came about, they two increased the likelihood that a hurricane would be seen and tracked. The continue advancement of technology has made keeping track of hurricane easier and more accurate.

The satellite era began back in April of 1960. That gave meteorologist a vastly improved platform for tracking tropical cyclones.  As Satellite, Radar, and computers advanced so did our understanding of and tracking of tropical cyclones increased.  The newer technology we now have allows us to see and analyze smaller storms, that may have gone unnoticed 10 or 20 years ago.  

The National Hurricane Center has a very difficult job; a job they handle very well. But over the last 5 years they have been naming storms that wouldn’t have been named before. I’m not going to say the NHC has some kind of global warming agenda, or that they are trying to pad the numbers. The NHC named several tropical cyclones in 2020 that lasted only for a day or less. As was the case during the 2019 season, some of these named storms formed over cold water. The NHC’s main goal is to save lives and property. So, while advanced satellite and computer algorithms allow us to detect storms that used to be undetectable; it might be a dual edged sword. In my opinion. Maybe it time to come up with a different criterion for naming storms.  Or maybe divide the Atlantic Basin into two separate hurricane seasons. 

The season is officially over, but that doesn’t mean we can’t have more tropical activity in December, it is 2020 after all.