Space Weather

Monday, October 12, 2020

How are my May Hurricane Outlook Predictions working out?

 

The 2020 Atlantic hurricane season runs from June 1 to November 30. The areas covered include the Atlantic Ocean, Gulf of Mexico and the Caribbean Sea.

 On May 20th I posted my 3rd and final outlook installment on the 2020 hurricane season.  

 In the outlook I concluded, “My call for the Atlantic Basin is that it will be hyperactive and one of the most active in history. 20-30 named storms, 9-14 hurricanes, 4-8 will become major hurricanes (Cat 3 or better). Ace index is going to be between 150 and 190.  I expect to see at least a few U.S. landfalls, some of them most likely will be major. Those along the Central and East Gulf Coast could see a very active season. The Mid-Atlantic Region and Northeast will also see an increased likelihood of tropical cyclone impacts, with at last a couple of landfalls very possible.”

 “The hyperactive season I’m forecasting doesn’t mean any storms will make landfall on the U.S (2010 is a good example). But the high number of tropical cyclones and the idea of above average homegrown activity, does greatly increase the odds. Regardless if this is an active season or not. It only takes one hurricane to bring devastation and loss of life. So, my advice is to be ready and prepare a plan just in case something comes your way.”

Part three of my 2020 hurricane outlook can be found here.

 As of right now, there have been a total of 26 tropical depressions, 25 named storms, 9 hurricanes, including 3 major hurricanes. Sadly, 151 people have lost their lives so far in the 2020 Atlantic hurricane season. 


The season so far breaks down to…

 Major Hurricanes: Laura, Teddy, and Delta

 Hurricanes: Hanna, Isaias, Marco and Nana, Paulette, Sally.

 Tropical Storms: Arthur, Bertha, Cristobal, Dolly, Edouard, Fay, Gonzalo, Josephine, Kyle, Omar, Rene, Vicky, Wilfred, Alpha, Beta, and Gamma

 Tropical Depression 10


What makes this year stand out?

 So far, other than Arthur, Bertha, and Dolly, every named system has been the earliest named letter storm on the historical record.  Every storm from Edouord to Delta has been a formation time record breaker Delta formed over 40 days earlier than its namesake did during the 2005 hurricane season.

 The years 2020 and 2005 are the only two in recorded history where forecasters ran out of approved storm names and had to resort to using the Greek alphabet. 

 Out of the nine hurricanes that have formed so far, five of them have struck the U.S.

 Delta's landfall in Louisiana made him technically the tenth named storm to hit the United States during the 2020 season, breaking the record set in 1916. Why do I say technically? Because I don’t think Marco was a bona fide tropical storm when it made landfall.  

 2020 Season has also seen another record; that being the most storms to have developed in the month of September. There were Ten named storms that developed during September. That breaks the previous record that was eight.

 2020 ties a record set in 1893 for the number of storms that formed on the same day. During September 2020 three named storms formed on the 18th, within the space of 6 hours. Back in 1893 three named storms developed on the same calendar day on 18 Aug. 1893.

 Most of the tropical cyclones that became at least a named storm, but did not cause significant damage or injuries. Which is a good thing. But with the number of 25 named systems, we would expect more damage. As I’ve said before a metric called Accumulated Cyclone Energy (ACE) is used to measure the overall activity of a season, factoring in duration and intensity of storms.








So, based on the number of storms and impacts my hurricane outlook has done very well. But my ACE forecast is still a bit high for an overall value for the 2020 hurricane season. As of October 12th, 2020, the Atlantic Ace Index Value stands at 123. Based on the 1981-2010 mean, an ACE index of 105.6 is considered average.  So yes, we’re running above average but only slightly.  So, while it is a very active season numerically it’s is only slightly to marginally active based on the ACE value…. Between 50 and 75 percent of the storms that have formed this year, were weak and very short lived; many of these systems wouldn't have even been named a few years ago. Also, the NHC has been starting to name systems in the far northern part of the North Atlantic, this practice has been occurring at an ever-increased pace the few years.  Why is the NHC naming storms well outside the tropics that form over cold water? I really don’t know… but IMO they are outside their purview when they do so

 But overall, I think my 2020 Atlantic Hurricane Outlook, has been right on the mark so far this season. The season ends on November 30th; so, we will see if the ACE value can come within the range I forecasted back in May.

 

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