The 2020 Atlantic hurricane season is not as busy as it seems.


Named storm tracks in the 2020 Atlantic hurricane season through July 7. The black footprint segments indicate when each storm became a low remnant.

(Data: NOAA / NHC)

  • We have already had five tropical storms in the 2020 Atlantic hurricane season.
  • Despite that high number, most of them have been short-lived.
  • The vast majority of the season is yet to come.
  • The key is how many storms and hurricanes hit the earth and where.
  • This is difficult to determine in a seasonal forecast.
  • Recent hurricane seasons illustrate the challenge in forecasting based solely on the number of storms.

The 2020 Atlantic hurricane season, so far, is just one example of why simply counting the number of tropical storms and hurricanes doesn’t tell the whole story.

Five tropical storms have already formed this season, through July 7.

Arthur and Bertha formed in May, before the hurricane season “officially” began. It was only the sixth time since 1851, in which two named storms formed before June 1, according to Colorado State University tropical meteorologist Phil Klotzbach.

Christopher and Edouard became the first of the season. and fifth Named storms on the record, according to Klotzbach.

So we are at a record early season rate for named storms, approximately 8 weeks before an average season, according to the National Hurricane Center.

Short-duration storms

The large number of storms so far masks the fact that these storms were short-lived.

Bertha turned into a tropical storm on May 27, then moved ashore an hour later near Charleston, South Carolina.

Dolly earned its name as a tropical storm on June 23, then became a low remnant of the North Atlantic less than 24 hours later. Edouard suffered a similar fate less than two weeks later.

Meteorologists use a measure called the ACE index, short for Cumulative Cyclonic Energy, not only to count storms and hurricanes, but also in their intensity and how long they last. Long-lived, intense hurricanes have a high ACE index. Weak tropical storms of short duration, low ACE index.

Given that these five tropical storms did not last long, it turns out that the season’s ACE index is not as anomalous, compared to the meager average through July 7, according to data compiled by Klotzbach.

2020 Atlantic Hurricane Season ACE Index through July 7 (left bar), Average Season ACE Index through July 7 (center bar), and Average ACE Index for an entire hurricane season (right bar).

(Data: Phil Klotzbach / CSU, NCAR RAL Tropical Cyclone Guidance Project)

According to this measure, 98% of the average activity of a hurricane season still remains after July 7.

If you consider hurricane season as a meal at your favorite restaurant, which I miss a lot due to the COVID-19 pandemic, we have ordered our food, we are drinking our drinks, but we have not had any snacks yet. .

Active season ahead

Seasonal forecasts continue to call for a hyperactive Atlantic hurricane season in 2020.

The last perspective published on Tuesday Colorado State University forecasts 20 named storms, nine of which will become hurricanes, and four of those hurricanes will become major hurricanes – Category 3 or higher (winds over 115 mph) on the Wind Scale of Hurricanes Saffir-Simpson.

This forecast is well above the 30-year average (1981-2010) of 13 named storms, seven hurricanes, and three major hurricanes. It also includes the five named storms that have already formed this season through Edouard, so they expect another 15 named storms to form until the end of the hurricane season.

In other words, if the hurricane season started today and we didn’t have five named storms, we’d still have an above-average hurricane season if the forecast comes true.

Numbers of named storms in the Atlantic Basin (those reaching at least one tropical or subtropical storm force), hurricanes and Category 3 hurricanes or higher intensity forecast by Colorado State University, NOAA and The Weather Company, a business from IBM, compared to the average 30 years (1981 to 2010). Each forecast includes named storms that have already occurred.

CSU’s latest perspective agrees with previously published perspectives by NOAA and The Weather Company, an IBM company.

There are a number of factors at play for what appears to be an active season ahead.

First, a vast stretch of the tropical and subtropical Atlantic Ocean is warmer than average. That warm water is not just shallow. The Caribbean Sea and some adjacent areas already have an impressive content of heat contained below the surface., according to an analysis by the University of Miami. This warm water reservoir is fuel for tropical storms and hurricanes.

Klotzbach also says that the lack of an El Niño and a robust West African monsoon They are also favoring an active season, preparing the atmosphere by decreasing hostile cutting winds and increasing the intensity of East African waves., the seedlings of most tropical storms and hurricanes in the Atlantic basin.

Recent Precautionary Stories About Counting Storms And Hurricanes

While an increased number of named storms and hurricanes increases the chances of making landfall, there is no strong correlation between the number of storms or hurricanes and landings in the United States in a given season.

For example, the 2010 Atlantic season tied for the second largest number of hurricanes (12) and the third best known storm (19) of any season since 1851.

Despite all that, only one tropical storm, and no hurricanes, made landfall in the continental United States.

Hurricane Earl caused a perplexing unrest on the east coast, skimming the Outer Banks of North Carolina before returning. Hurricane Alex made landfall in Northeast Mexico, but caused some flooding in South Texas.

So the season was very active, but the continental impact of the US was relatively low, as the winds that controlled each storm or hurricane acted to keep them largely away.

Footprints of all storms and hurricanes in the 2010 Atlantic hurricane season. Only one tropical storm, Bonnie, made landfall in the continental United States in 2010, despite the large number of storms and hurricanes. Tracking segments in black indicate when each storm became a low remnant, or was in its pre-depression phase.

(Data: NOAA / NHC)

We’ve also seen seemingly inactive stations offering the only major landing.

The 1992 hurricane season produced only seven storms. However, one of them was Hurricane Andrew, which devastated South Florida as one of only four hurricanes to make landfall in the US with Category 5 intensity, easily the most expensive hurricane in the nation, at the time.

HURRICANE ANDREW (1992)

Aerial view of a mobile home community in Dade County, Florida, devastated by Category 5 Hurricane Andrew in August 1992.

(Bob Epstein / FEMA)

1983 was even quieter than 1992.

Only four named storms, yes, one storm with less name than we’ve seen so far in the 2020 season, ran the entire season, the smallest of any Atlantic hurricane season since 1930.

But one of those four was Alicia.

This Category 3 hurricane hit the Houston metropolitan area with strong winds that shattered glass in the city’s skyscrapers, claimed 21 lives and was, in itself, a billion dollar disaster.

Named storm tracks from the 1983 Atlantic hurricane season. Despite just four named storms, one of them, Alicia, was a billion-dollar disaster in Texas

A hurricane season can cause many storms, but have little impact, or generate few storms, but one or more hit the US with a major impact.

That’s why residents in the hurricane zone must prepare every year regardless of the seasonal forecast.

A recent streak of luck ended with an avalanche of landings

United States averages one or two hurricane landings each season, according to statistics from NOAA’s Hurricane Investigation Division.

In 2019, there were two hurricane hits in the United States: Barry in Louisiana and Dorian in North Carolina.

(PLUS: Why Hurricane Dorian of 2019 was not withdrawn by the World Meteorological Organization)

In 2018, four named storms hit the U.S. coast, notably Hurricanes Florence and Michael a month apart.

In 2017, seven named storms hit the U.S. coast, including Puerto Rico, especially Hurricanes Harvey, Irma, and Maria, which hit Texas, Florida, and Puerto Rico, respectively.

Before that, the United States was on a lucky streak.

According to Alex Lamers, the cumulative 10-year total of American hurricanes from 2006 to 2015 was seven., meteorologist of the National Meteorological Service. This was a record low for any 10-year period dating back to 1850, and considerably lower than the average of 17 per 10-year period. in that same period.

None of the landings in the United States from 2006 to 2015 came from major hurricanes.

Therefore, it is impossible to know for sure if one or more hurricanes will occur in the United States this season. Even a faint tropical storm hitting the US can cause major impacts, especially if it moves slowly and causes flooding.

(PLUS: How fast or slow a hurricane moves can be as important as its intensity)

While you should prepare for hurricane season every year, it is very important to do so this year.

The Weather Journal’s primary journalistic mission is to report on the latest news from the climate, the environment and the importance of science in our lives. This story does not necessarily represent the position of our parent company, IBM.

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