2012 - The Year in Review, Volume II: Ernesto - Gordon
2012 - The Year in Review
Good afternoon and welcome to my Year in Review. This hurricane has been by all accounts deadly and destructive. As it stands right now, the final totals are 19-10-1 (subjected to change during post-season analysis) this once again ties us for the third most active hurricane season with 2011, 2010, 1995, and 1887, with 320 fatalities, 180 of those being in the United States. This season is the second most destructive on record, with an estimated 68-70 billion dollars in damages. Most of these were from Hurricane Sandy, which was the second most destructive hurricane ever strike the United States, only behind Hurricane Katrina.
July went by with no named storm, causing many, myself included, to assume that was a sure sign that even though we've had an active May and June, the rest of the season would be benign. The next storm on the list would be first noted on the Tropical Weather Outlook on the 29th of July, it slowly organized the next day until the 1st of August, were it was found to have a closed circulation and advisories were issued on Tropical Depression 5, east of the islands.
(Figure 1. Tropical Depression 5 around the time of classification)
There were several issues against Tropical Depression 5, one of which was the dry air penetrating its core, another was the fast forward speed, and the fact it was dependent on the ITCZ for development. Nonetheless, the system became Tropical Storm Ernesto midday on August 2nd, 2012. It was assumed that intensification would be gradual across the Caribbean, and the storm could become a major system as it entered the Western Caribbean. However, many of the models were not excited about this system, in particular the ECMWF model. This was due to the fast trade winds in the Eastern Caribbean that plague systems in that area. Because of this, Ernesto became quite disorganized in its journey throughout the Caribbean. Thought it was able to generate strong convection, it was unable to hold it due to the misalignment of the low-level circulation and the mid-level circulation, causing intensification to only peak around 50mph.
(Figure 2. Ernesto struggling in the Central Caribbean)
Meanwhile, while Ernesto was trying to get past the Eastern Caribbean, another tropical wave behind Ernesto began to develop by the 2nd of August, it quickly became better organized and was declared Tropical Depression Six on the 3rd of August. The system organized slowly, due to an abundance of dry air in the vicinity, and became Tropical Storm Florence the next day. However, this dry air combined with shear weakened the system, causing it to dissipate on the 6th, having only reached a peak of 60mph.
(Figure 3. Tropical Storm Florence at peak intensity)
However, the trade winds were acting to 'pile up' in the Western Caribbean as an upward Madden-Julian Oscillation (MJO) phase came to our basin. Because of this, it seemed likely that intensification to a hurricane would occur as it approached the Yucatan. Intensification finally began on the 6th, while the system was entering the extreme Western Caribbean. Around noon on the 7th, Ernesto finally became a Hurricane and began to quickly intensify just before its landfall in Belize. The system made landfall late in the day as an 85mph system. Observations from several platforms indicated the system was probably stronger, perhaps around 90-95mph with a minimum pressure of 977mb, so if these are deemed reliable, it is possible we could see an upgrade to Category 2 status in the post season.
(Figure 4. Hurricane Ernesto at landfall)
Ernesto weakened as it went inland, though it appeared the system might re-emerge and intensify back into a hurricane over the Bay of Campeche, this failed to really happen as the system only managed to intensify back into a 70mph tropical storm before dissipating on the 10th. Its remnants later went on to become Tropical Storm Hector in the Eastern Pacific.
The same day Ernesto made landfall in Mexico, another tropical wave behind Florence began to develop as it approached the Caribbean islands, and was declared Tropical Depression Seven on August 9th, 2012 east of the islands. TD7 suffered many of the same issues Ernesto had just gone through, and the strong trade winds acted as its downfall. Unlike with Ernesto, TD7 was smaller, did not draw on the ITCZ for energy, and was barely closed as it was. This caused the system to degenerate back into a Tropical Wave on the morning of the 11th.
(Figure 5. Tropical Depression Seven before its classification)
This was not the end for TD7 by all means, as many models were thinking that like with Ernesto, TD7 could begin to reorganize in the Bay of Campeche. This appeared less likely on the 14th, when the storm made landfall in Central America. However, it managed to have its low-level center move northward and regenerate into a tropical cyclone in the extreme south Bay of Campeche on August 17th, 2012, and was declared to become Tropical Storm Helene. Helene did not have long, as it was already approaching landfall. Dry air and land disruption quickly began to take its toll, and the system quickly dissipated on the 19th as it moved inland into Mexico.
(Figure 5. Tropical Storm Helene around the time of classification)
Meanwhile, on the 10th of August a tropical wave moved off the coast of Africa. It appeared this system would be similar to Ernesto, Florence, and TD7. However, it moved far more north than expected and ran straight into an area of dry air, destroying the circulation. This appeared to be the end for said disturbance, until it had cleared the dry air layer on the 13th. Gradual organization continued, and the system was declared to have become Tropical Depression 8 on the 15th of August, in the north-eastern Central Atlantic. Intensification appeared likely, thanks to warm waters in the area, and was predicted to peak as a hurricane after its classification. Early on the 16th, the system had been declared to have enough organization to become Tropical Storm Gordon, the 7th named storm of the season.
(Figure 6. Gordon around the time of classification)
The system was very small, and compact. This combined with its forward speed and good conditions, it appeared that it was possible the system could intensify further than predicted. However, it was also predicted to get quite far north, and approach the Azores. Tropical Storm watches were issued for the islands on the 17th. The system continued to organize, and was declared to have become Hurricane Gordon on the 18th, while at 34.0 degrees north. Rapid intensification ensued, and Gordon quickly became a 110mph Hurricane the night of the 18th. Some of the data from satellite indicated it was possible that the system had become a major hurricane, and it is possible the system will be upgraded as such in the post season.
(Figure 7. Gordon the day before peak intensity, having become a hurricane)
After that, as Gordon reached cooler waters, weakening began in earnest, and was declared to have become post-tropical late on the 20th, moving well away from the Azores.
I had planned on doing up to Leslie, but it's quite late at night for me. So I will have a follow up tomorrow or Thursday with Isaac, Joyce, Kirk, and Leslie.