CybrTeddy's tropical weather blog

2011 - The unusual Atlantic Hurricane season. 11/25/11

By: CybrTeddy, 6:13 PM GMT on November 25, 2011

Good afternoon and welcome to my year review of this very unusual hurricane season. The 2011 Atlantic hurricane season was tied with 1995, 2010, and 1887 as the 3rd most active hurricane season ever recorded. 2011 killed over 150 people, and caused more than 11 billion dollars in damages, mostly due to Irene and Lee's flooding rains. This season in most respects, did indeed live up to the expectations. The general idea in May was that this season would be active, maybe not as active as 2010 (which was proven wrong), but would feature more systems developing closer to land. However, this season trough splits seemed to dominate off the US east coast. Bret, Cindy, Franklin, and an unnamned Tropical Storm all developed off from trough splits. These systems where generally weak and stayed away from land. The main, meaty systems we saw this year where Irene, Katia, Ophelia, and Rina. These 4 systems stole the year in terms of intensity and forecasting, with Irene being the first hurricane to hit the United States since Hurricane Ike in 2008.

(fig 1. The 2011 Atlantic Hurricane season final map.)

June - August. Act I. An exceptionally active first half of the season.
Through the first half of the 2011 Atlantic hurricane season, it was so active that it was generally tied or just one named storm behind 2005, however the lack of hurricanes was very obvious. We did not get our first hurricane until Major Hurricane Irene in August. There had never been a recorded instant that the first 7 named storms did not become at least a Category 1 hurricane.

Tropical Storm Arlene brought the season in, in a very similar manner to Hurricane Alex of 2010, albeit weaker, the genesis and track of Arlene and Alex, as well as the size and structure, where about the same. Arlene lasted from June 29 – July 1, and had maximum sustained winds of 65 mph and a pressure of 993 mb at peak, pending TCR. Arlene developed monsoonal in nature and eventually found its way into the Bay of Campeche, where genesis occurred. Arlene caused 222 million dollars in damage to Mexico, and killed 19 people.


Tropical Storm Bret developed in July from a trough split off the United States. From July 17 – July 22, Bret meandered off the Eastern seaboard, and at one point gained an eye. Dry air and wind shear however prevented Bret from becoming a hurricane, but it got fairly close to obtaining hurricane status. Bret did not affect land, and no damage or deaths where attributed to him.


Tropical Storm Cindy was at first a competing circulation with the developing Bret, and formed off the same front. Originally shown by the models to be extra-tropical, Cindy split off and rapidly developed to have a eye, and a eventual peak of 70 mph in the Atlantic. Cindy did not affect land.


Tropical Storm Don was a weak tropical storm that developed north of the Yucatan from July 27 – July 30. Don was a very meager storm from its inception, and struggled to grow into a very potent system. Don was in short, pathetic, and died as soon as it touched the Texas soil. This was thanks to the extreme drought and dry air that was around Texas at the time. The very thing Texas needed the most was killed by Texas.


Tropical Storm Emily was another meager tropical cyclone that developed in the Caribbean sea. From August 1 – August 7, Emily traversed the Caribbean and eventually found its way off Florida, but that was only before dissipating on the 4th of August. Emily at first was predicted to approach Florida as a Category 1 hurricane, but only managed to get into the Bahamas as a barely-depression. Emily caused little damage and took the lives of 5 people from flooding.


Tropical Storm Franklin formed off a trough split off the Eastern Seaboard. Franklin was very short lived, from August 12 – August 13 it obtained a brief peak of 45 mph and a pressure of 1004 mb before weakening back down to a extra-tropical system. Franklin caused no deaths.


Tropical Storm Gert formed from a non-tropical low pressure area in the Central Atlantic south of Bermuda. It eventually developed and obtained a peak strength of 65 mph from August 13 – August 16. Radar from Bermuda revealed Gert had a well formed eye and a developing eyewall and peak intensity, but hurricane hunters failed to find any indication that Gert obtained hurricane status, as such Gert only remained a 65 mph system and dissipated a few days later without affecting land.


Tropical Storm Harvey formed from a tropical wave that looked prime to become our first Cape Verde system when it emerged off the coast. However dry air knocked the tropical wave back down and allowed it to continue westward into the Western Caribbean eventually. From August 18 – August 22, Harvey developed north of Central America and made landfall in the Yucatan as a 60 mph Tropical Storm with a pressure of 994 mb. 3 deaths are associated with Harvey's landfall, from flooding rains.


Major Hurricane Irene was the highlight of the season for the United States. Irene was the first hurricane to make landfall in the United States since Hurricane Ike in September 2008. Irene continued the curse of the ''I'' named, and will more than likely be retired. Irene developed west of the islands, and quickly was tagged as a tropical storm as it approached the islands. Irene was predicted by all the models to become a strong system if it did not interact with Hispaniola. It appeared at first Irene would take a similar track, but much stronger, that Emily took a few weeks prior. Irene hit Puerto Rico dead on as a Hurricane and continued to go north of Hispaniola.

Over the Bahamas, Irene strengthened further to become a 120 mph Category 3 hurricane at peak intensity. Originally forecasted to become a Category 4 hurricane, Irene managed to go through an eyewall replacement cycle, and dry air got into the core. As Irene approached the United States, it eventually weakened to a Category 1 hurricane when it made landfall, but with an unusually low pressure, >955 mb. Irene also had massive storm surge, as would be expected with such a large system. Irene then became the first hurricane in nearly a century to make landfall in New Jersey, and continued to weaken to a Tropical Storm by the time it was going extra-tropical over New York City. Irene killed 56 people, and caused 10.1 billion dollars in damages, making it one of the top 15 most destructive hurricanes ever. Irene will more than likely be retired in the spring of 2012.


Tropical Storm Jose developed from August 28 – August 29, and was an extremely meager system. Jose did not effect land, and was a very controversial system still, as many people pointed out the inconsistencies of the NHC when it comes to naming systems.


Major Hurricane Katia was a powerful, long lived Cape Verde system from August 29 – September 10. Katia emerged off Africa and quickly managed to develop into a tropical cyclone, and was predicted to become a Hurricane. For the first few days, Katia had trouble with dry air, obtaining hurricane status then being knocked back down to a tropical storm. Eventually, on its NW path Katia found a sweet spot that several storms earlier in the year had enjoyed, and strengthened to its peak as a 135 mph Category 4 hurricane. Katia continued NW, then re-curved well to the East of the United States.


A unnamned Tropical Storm developed the same day Lee was classified. The TCR and satellite images are not yet out, but this was confirmed by the National Hurricane Center just yesterday.

Tropical Storm Lee was the most destructive Tropical Storm since Allison in 2001. Lee developed from September 1 – September 5, with maximum sustained winds of 60 mph in the Gulf of Mexico south of Louisiana. Lee was a disorganized tropical cyclone, but did have loads of rainfall - one of a tropical cyclone's most dangerous weapons. When it made landfall, Lee caused dangerous flooding all up the United States and tornado outbreaks, eventually causing damage over >1 billion dollars in damages. I am not sure if Lee will be retired, as the damage was caused after Lee's death and was merging with another system, but its entirely possible that Tropical Storm Lee will be retired in 2012.


Hurricane Maria was at first a meager, long lived Tropical storm that nearly dissipated as it approached the islands. It encountered the same sweet spot that Hurricane Katia did, and strengthened to a Category 1 hurricane as it made landfall in Newfoundland. From September 6 – September 16, Maria managed to become a 80 mph Category 1 hurricane with a pressure of 979 mb. Maria was the first time that a hurricane made landfall in Newfoundland two years in a row, as last year Major Hurricane Igor made landfall there as well.


Hurricane Nate was just recently upgraded to a hurricane in its TCR. A stationary low pressure area developed on September 7th to become rapidly Tropical Storm Nate. Nate the next day briefly obtained Hurricane status, but weakened from its own up welling quickly. Nate weakened to the point where it was barely a few clouds, and eventually made landfall in Mexico causing little damage.


Major Hurricane Ophelia was my personal favorite system of the year, if you can favorite hurricanes. Ophelia's existence was at first similar to Maria, and dissipated as it approached the islands. However, Ophelia regenerated and rapidly developed into a Category 4 hurricane, an extreme occurrence for October. No one expected it, I certainty didn't expect that meager tropical storm to become the strongest hurricane of the year. Ophelia peaked at 140 mph with a pressure of 940 mb, a record for that latitude that late in the season.


Hurricane Philippe continued the strain of pathetic Cape Verde tropical storms that reached hurricane strength as they recurved out to sea. Philippe developed as the last Cape Verde system of the year, and developed into a hurricane. Philippe was one of the longest lasting tropical storms ever before becoming a hurricane.


Hurricane Rina was one of the fastest developing hurricanes on record, going from a TD to a Category 1 hurricane in the same time frame as Hurricane Humberto. It is interesting to note how this has happened every single year since Humberto. Lorenzo in 2007 also did so, Gustav in 2008, Ida in 2009, and Paula in 2010 also all became hurricanes in under 20 hours, leading me to believe this is a disturbing trend and should be watched, as we do not want hurricanes to suddenly pop off the coast and make landfall. Anyways, Rina rapidly weakened after obtaining its peak of 110 mph, predicted to become a 120 mph Category 3, its upwelling and dry air got into the core and prohibited strengthening. Rina caused little damage and no deaths are contributed to Rina.


Our final system of the year developed from a sub-tropical area of low pressure. This system eventually developed into Sub-Tropical Storm Sean, and eventually became fully tropical. It is unknown of Sean obtained hurricane status, however basing off the recon reports, I would say that Tropical Storm Sean became Hurricane Sean before weakening, that will be decided though its in TCR later this year.


In conclusion, the 2011 Atlantic hurricane season was a strange one. Most of the storms this year where relatively weak and meager, and with the exception of Rina and Irene, the storms that did become hurricanes stayed away from land, causing little in the way of damage. Only Irene will probably be truly remembered this year, as it caused heavy damage and destruction across the Eastern Seaboard and was the first CV hurricane to hit the Eastern Seaboard, and the most destructive since Hurricane Isabel, and being the first since Hurricane Gaston in 2004.

It is too early to say what might be in store for the 2012 Atlantic hurricane season, but I will be publishing my first predictions in January, followed by my spring predictions in March, and my June predictions on the 1st of June, as well as a real return of my daily updates.

Until then, farewell.

CybrTeddy, signing off for 2011. See you guys next year!


The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.