Hurricane Igor (2010)

Storm Active: September 8-21
On September 6, a strong tropical wave emerged off of Africa. A low became associated with the system on September 7, and the system continued to organize, despite significant shear. On September 8, the system was organized enough to skip the tropical depression stage and intensify directly into Tropical Storm Igor.

The convection and circulation of Igor were at a very high level of organization, even with two low pressure systems in the vicinity. These three lows shared a low pressure trough extending from just off Africa to a few hundred miles north and west, but Igor began to strengthen later on September 8, and asserted its dominance. Igor meandered slowly to the west, before taking a turn north and then northwest on September 9. As it moved into greater shear, it weakened, becoming a tropical depression later that day, as the center became exposed from the east side. Despite this, the circulation deepened, the convection became more organized, and the system regained tropical storm status the next day. The shear had abated once again and Igor began to strengthen. During the morning of September 11, Igor developed an interesting eye feature on the north side of the system, and the storm approached hurricane strength. However, convection decreased during the afternoon before a burst of convection during the evening caused Igor to become a hurricane.

An eye became evident within this convection early on September 12, and Igor underwent explosive strengthening, ballooning from a minimal hurricane to a amazing Category 4 by that afternoon as a result of a drop of 50 mb in 12 hours. Igor's forward motion slowed and the system moved due west throughout that same day. Igor continued to strengthen, reaching an intensity of 150 mph late on September 12, and this remarkable intensity was maintained throughout the day of September 13, as a beautiful symmetric eye dominated the system. By that evening, surf began to increase in the Northern Leeward Islands as Igor approached from the west. Igor made a slight westnorthwest turn that night, and an eye replacement cycle destabilized the system, weakening it. However, it remained a Category 4 through the day of September 14, before organizing further and strengthening once again during the evening. Igor reached a peak intensity of 155 mph and a pressure of 925 mb later that night before the eye clouded over and a weakening trend commenced.

However, Igor organized once again, and the fluctuations in intensity continued as Igor became a powerful Category 4 once more with 145 mph winds. The convection became slightly asymmetrical, with the bulk of the cloud cover on the north side on September 16, but the moisture evened out during the evening as a a pronounced rain band formed south of the center. Also, during the day of September 16, Igor's tropical storm wind field broadened to 506 miles in diameter, making it the third-largest Atlantic hurricane on record. Igor began weakening, however, and finally lost it's Category 4 status during the late afternoon of September 16, after maintaining it for four days. The system continued to weaken over the next day. By the afternoon of September 18, Igor was a Category 2, but the windfield was still broadening, and squally weather was already sweeping over Bermuda. By later that night, Igor's tropical storm force windfield engulfed Bermuda, and the winds increased throughout the day, despite the fact that Igor weakened to a Category 1.

The center of Igor passed just to the west of Bermuda late on September 19, and the island saw sustained winds near hurricane-force as a result. Igor accelerated northeastward, and maintained a minimal hurricane status while the extratropical transition began on September 20. However, this transition wasn't completed by the time Igor passed Newfoundland, and the center passed just to the east of the island, causing sustained winds near hurricane force and dumping over 9 inches of rain in some areas, causing flooding. Igor finally became extratropical on September 21. Igor caused 3 fatalities and about $100 million in damage. The cyclone was also notable for being the largest Atlantic hurricane ever recorded, with a tropical storm force wind diameter of 920 miles, until it was surpassed by Hurricane Sandy of 2012.



Igor near peak intensity.



Track of Igor.

Tropical Storm Hermine (2010)

Storm Active: September 5-7
On September 3, a low pressure system formed in the eastern Pacific and quickly became Tropical Depression Eleven-E. However, the system made landfall in Mexico the next day without becoming a tropical storm. The remnant low of the system moved into the Bay of Campeche on September 5 and began to organize again. The low was associated with a very large area of showers and thunderstorms covering a significant portion of the western Gulf of Mexico. Late on September 5, the system was organized enough to be upgraded to Tropical Depression Ten. Ten quickly strengthened, and became Tropical Storm Hermine early on September 6.

Hermine quickly organized, and began rapidly strengthened as it moved generally to the north. Hermine reached its peak intensity of 65 mph winds and a minimum pressure of 991 before making landfall in extreme north Mexico late on September 6. Hermine crossed the U.S.-Mexico border inland a few hours later, as it steadily weakened. Hermine maintained minimal tropical storm status for a fairly long time inland, but finally weakened to a tropical depression by the evening of September 7. By later that night, it was no longer monitored by the national hurricane center, but it still maintained tropical depression status, as it tracked northward through the central U.S. The depression merged with a frontal boundary on September 9. The remnant moisture combined with the frontal system caused heavy rain from the midwest to the northeast over the next couple of days, before moving off the coast on September 12.



Hermine inland over Texas, still maintaining tropical storm strength and a healthy outflow.



Track of Hermine.

Tropical Storm Gaston (2010)

Storm Active: September 1-2
A tropical wave emerged off of Africa on August 29, and immediately began to organize, developing a low pressure center rapidly. By the beginning of September, a defined center had formed, and the system became Tropical Depression Nine early on September 1. The depression quickly crossed the border to tropical storm strength and was named Tropical Storm Gaston.

However, some Saharan dry air was still embedded in the system, preventing deep convection in the center. Meanwhile, the cyclone was tracking only very slowly westward, due to the presence of a trough to its north. The dry air present in the system weakened Gaston to a tropical depression and then a remnant low by the afternoon of September 2. However, early on September 3, convection associated with the remnant increased, and organization continued to increase over the next few days. Despite this, the low lost its good circulation, and, although convection persisted, the chance of development was significantly decreased by September 7 as it passed through the Caribbean. On September 8, the low dissipated. Gaston affected no landmasses and therefore had no impact.

Note: It is believed that the remnants of Gaston may have briefly attained tropical depression status again on September 4, but post-season analysis will confirm this after the conclusion of 2010.



Gaston on September 4, possibly a tropical depression.



The track of Gaston, with appropriate changes made from post-storm analysis.

Tropical Storm Fiona (2010)

Storm Active: August 30-September 3
On August 26, a strong tropical wave emerged off the coast of Africa, adopting the same general track of Danielle and Earl before it. By later that same day, a low pressure center became embedded in the wave. Although the outflow and circulation of the system was very organized from the beginning, convection remained minimal and a tropical depression didn't form during the next few days. On August 28, a burst of convection appeared at the center, but it ebbed away over the next day. By August 30, the system was producing tropical storm force winds, and a center was found, causing the low to be promoted to Tropical Storm Fiona, with no intermediate tropical depression stage.

Its initial intensity was 40 mph winds and a pressure of 1007 mb. Fiona sped off to the west and westnorthwest over the next day, and tropical storm watches were issued for some of the Northern Leeward Islands in preparation for possible tropical storm conditions in areas that were still recovering from Hurricane Earl. Fiona's motion was at least 20 mph until September 1, when the presence of Earl to its east slowed its motion. The outflow of Earl and Fiona kept a certain distance between the two, and Fiona actually became more organized as it slowed down, unexpectedly strengthening into a strong tropical storm by the morning of September 1, with winds of 60 mph. However, later on September 1, Fiona peaked at 60 mph and a pressure of 997 mb, before losing most of its cloud cover and weakening. Meanwhile, it turned to the northwest and sped up again through the morning of September 2. Fiona recovered some convection during the day, but intense shear exposed Fiona's circulation, and as it turned north, it continued to weaken. As Fiona struggled north-northeast, its pressure rose further, and it weakened to a tropical depression and then a remnant low late on September 3, before even reaching Bermuda.

The only effects of Fiona were some showers and gusty winds in the Northern Leeward Islands and Bermuda.



Fiona at peak intensity on September 1, despite the exposure of its circulation.



Track of Fiona, notable for coinciding almost exactly with that of Tropical Storm Colin earlier that year.

Hurricane Earl (2010)

Storm Active: August 25-September 4
On August 23, a strong tropical wave emerged off of Africa and immediately began to show signs of organization. The wave developed a low pressure center on August 24, and during that day, brought rain and gusty winds to the Cape Verde Islands. However, the system did not possess a closed circulation until August 25, and was then declared Tropical Depression Seven. Upon formation, Seven was already on the verge of tropical storm intensity and in another six hours, during the afternoon on August 25, the system became Tropical Storm Earl.

Overnight, the outflow of the system grew very organized, suggesting strengthening, but the location of the center itself was a moving target, reforming every few hours in a slightly different location relative to the convection. The center became more defined with a burst of convection during the evening of August 26, but the system did not undergo significant intensification overnight. Earl persisted westward during the day of August 27, and tropical storm watches were issued for portions of the northern Leeward islands as a result. Meanwhile, Earl began to strengthen, reaching strong tropical storm intensity by August 28. Despite an early turn north on the models, Earl continued west much longer than expected, and continued strengthening. Earl attained hurricane strength on August 29, and hurricane watches and warnings were issued for parts of the Northern Leeward Islands.

Finally, Earl turned westnorthwest later that day, but the outer bands of Earl began to sweep across the northeasternmost islands of the Caribbean bringing heavy rains and wind, with conditions getting progressively worse into the evening hours. By 8:00 pm EDT that night, tropical storm force surface winds covered the northern Leeward Islands, and hurricane force sustained winds also brushed these areas causing intense storm surge and flooding. Meanwhile, Earl continued to gain strength and rapidly became a Category 2 very late on August 29 and was on the verge of major hurricane strength by the morning of August 30. An eye appeared in Earl during the day as it strengthened rapidly, becoming a major hurricane quickly and then a Category 4 as it passed north of the U.S. Virgin Islands and Puerto Rico and caused tropical storm force winds and rain throughout the regions. Earl's pressure continued to drop, and by August 31, Earl had reached an amazing intensity of 135 mph winds and a 931 mb pressure. It still maintained a general westnorthwest motion, and the eye clouded over somewhat as Earl went through the Eye Replacement Cycle. The pressure rose as the cycle progressed, and Earl turned northwest, passing east of the Bahamas. But Earl maintained a Category 4 intensity until September 1, when it encountered some more significant shear and weakened to a Category 3 hurricane. Earl slowly turned to the north-northwest and recovered an eye, becoming more organized during the afternoon of September 1, and it restrengthened into a Category 4 hurricane. It surpassed its previous peak in intensity and reached its primary peak of 145 mph winds and a pressure of 928 mb early on September 2!

The storm continued to approach the Outer Banks of North Carolina during the day. By that evening, rainbands and tropical storm force winds swept over Cape Hattaras and the surrounding areas, as Earl turned north-northeast. However, hurricane force winds stayed offshore. As Earl approached, the eye clouded over again and Earl began steadily weakening, to a Category 3, and then a Category 2 by the time it passed by Cape Hattaras early on September 3. The weakening continued, and Earl was a tropical storm by the time it brushed passed Cape Cod overnight, bringing tropical storm force winds and rain to that area as well. By September 4, conditions were deteriorating in Nova Scotia. During the day, Earl made landfall in Nova Scotia and then Prince Edward Island as a powerful tropical storm, before entering the Gulf of St. Lawrence and finally becoming extratropical late on September 4 just off the coast of northeast Quebec. In total, Earl caused $150 million in damages and 3 fatalities over the areas it affected.



Earl nearing its peak intensity east of the Bahamas on September 1.



Track of Earl.

Hurricane Danielle (2010)

Storm Active: August 21-30
On August 19, a broad area of low pressure formed just of the coast of Africa and quickly developed deep convection due to its proximity to the Intertropical Convergence Zone. Over the next day, the system developed two centers along the trough, one on the eastern side, toward Africa, and one on the western side. The one on the western side was 1008 mb, as opposed to the eastern's 1011 mb, and the former soon gained dominance as the other dissipated. During the day of August 20, the system remained disorganized. However, during the afternoon on August 21, a closed circulation formed, and a very apparent spin appeared on satellite images, and the disturbance was classified Tropical Depression Six that day with 30 mph winds and a pressure of 1008 mb. Six strengthened as it moved westnorthwest, and a burst of convection near the center merited an upgrade to Tropical Storm Danielle during the afternoon of August 22.

Favorable conditions with warm water and minimal wind shear allowed Danielle to strengthen significantly through the night and into August 23. By the afternoon of that day, Danielle reached hurricane strength and was still rapidly intensifying. Also, contrary to previous models, Danielle still continued on a generally westnorthwestward track overnight and into the next day. During the early morning of August 24, Danielle reached Category 2 hurricane strength. However, a dry air mass embedded itself in the system during the afternoon, briefly exposing the center! This caused Danielle to weaken to a tropical storm by the evening, but already it had recovered and started to regain strength. By early on August 25, Danielle's movement slowly was shifting to the northwest, although it was still westnorthwest for much of the morning.

The system was also a hurricane again by this time and gaining intensity. Danielle maintained an intensity of 85 mph winds and a pressure of 982 mb through the day, and turned northwest during the evening. Also, an eye feature began to develop during the night, albeit an asymmetrical one, as Danielle once again became a Category 2 hurricane. The eye had been clouded over due to the Eye Replacement Cycle, but Danielle still gained intensity into August 26. Danielle redeveloped a well-formed eye during the day, and its movement to the northwest slowed as a trough interfered with its motion. Danielle continued to strengthen, becoming the first major hurricane of the 2010 season at 2 am EDT on August 27, and became a Category 4 just three hours later with an amazing intensity of 135 mph winds and a minimum central pressure of 946 mb. Later that day, Danielle achieved its peak intensity of 135 mph winds and a central pressure of 942 mb.

After that, Danielle began to be exposed to some wind shear and cooler waters, resulting in some weakening. Danielle lost its major hurricane status early on August 28, and continued its downward trend during that day as it turned to the north. During the day of August 28, Danielle, despite being over 1000 miles from the east coast, influenced the surf along the coastline, and created 3-6 foot waves and rip currents, killing one person in Florida. However, a trough moving off the east coast picked up Danielle and began to steer it to the east. That evening, Danielle's circulation broadened and became asymmetrical, marking the beginning of its extratropical transition. This transition continued into August 29, as the cyclone accelerated northeast and weakened to a Category 1 hurricane. By August 30, it was clear that Danielle was nearly extratropical and barely holding on to minimal hurricane strength, but it somehow stayed tropical through the day and turned more eastward, weakening to a tropical storm. However, by 11:00 pm EDT on August 30, Danielle had become fully extratropical and the last advisory was issued.

Danielle's remnants became embedded in a frontal boundary the next day, and it dissipated soon after as it sped off to the east. No damage and 1 indirect death occurred from Danielle.



Danielle near peak intensity over the open waters of the Atlantic.



Track of Danielle.

Tropical Depression Five (2010)

Storm Active: August 10-11
On August 8, a stationary frontal boundary off the east coast of the United States developed a low pressure system at its southern end. The force of high pressure systems to the west pushed the low south, where it encountered the typical west to east motions of the lower latitudes, and tracked over Florida on August 9, emerging over the Gulf of Mexico on August 10 as a 1010 mb low. The pressure continued to drop, and the circulation became organized enough to be declared Tropical Depression Five at its peak intensity of 35 mph winds and a pressure of 1007 mb. However, the convection associated with the system never attained definition with respect to the center, and the low weakened as it moved northwestward. The low dissipated before even reaching the Gulf coast on August 11. The broad area of low pressure associated with the dissipated Tropical Depression Five combined with a stationary front inland over the Gulf states in August 13. The system once again tracked southeastward, and approached the Gulf, intensifying as it went. As the low deepened, it became detached from the front, and by early on August 16, the system was a powerful 1010 mb low entering the Gulf with a fairly impressive clump of convection. However, no closed circulation formed, and the low made landfall once again in Louisiana without achieving tropical characteristics. The low moved north and dissipated.



Five in the Gulf of Mexico.



Track of Five.

Tropical Storm Colin (2010)

Storm Active: August 2-8
On July 29, a low pressure system formed in the southeast Atlantic and slowly drifted westward. The low became associated with a large area of showers and thunderstorms, but the system remained disorganized. A tropical wave accompanied the low as it drifted westward, but the wave disengaged from the circulation, and convection decreased. However, another tropical wave, moving off of Africa combined with the low during the day of July 31, and the systems had totally merged by August 1. However, this time convection persisted within the system and it organized. A flare up of convection that defined the system's center marked the formation of a closed circulation and the system was declared Tropical Depression Four on August 2. Tropical Depression Four's initial movement was swift, to west at 17 mph, due to the steering force of a subtropical ridge to its north. Overnight, Four became more organized, and it was upgraded to Tropical Storm Colin, with 40 mph winds and a pressure of 1006 mb, during the morning of August 3.

Colin accelerated to the west at an even greater speed, reaching a velocity of nearly 25 mph during the day on August 3. Then, the low pressure associated with the system became open, and it degenerated into a remnant low. However, cloud cover persisted within the system, and a new surface low pressure center became evident late on August 4. The system continued to organize, and was redesignated Tropical Storm Colin on August 5. Colin moved northwest and slowed in movement as it encountered a high pressure system, and began to turn east, as with most cyclones in the region. It briefly attained an intensity of 60 mph winds and a pressure of 1005 mb before the circulation became widely separated from the cloud cover again and Colin weakened to a weak tropical storm (45 mph winds) by August 6. Colin became nearly stationary on August 7, and weakened further, barely a tropical storm by the time it resumed movement to the northnortheast later that day. As Colin approached Bermuda, it weakened into a tropical depression, and brought needed rain to the island. Soon after passing west of Bermuda on August 8, Colin lost its circulation and dissipated.



Tropical Storm Colin shortly after reforming on August 5. The circulation, although more organized than before, is clearly exposed.



Track of Colin.

Tropical Storm Bonnie (2010)

Storm Active: July 22-24
On July 14, a tropical wave emerged off of Africa and moved westward. By July 17, the wave became associated with a broad upper-level low. However, very little storm activity accompanied the system at that time, as it moved westnorthwestward. On July 18, cloud cover increased in the system, but the circulation remained in the upper levels, prohibiting development. Over the next few days, the surface pressure began to drop and heavy rain from the system caused widespread flooding in Puerto Rico and Hispaniola. On July 22, a surface circulation appeared, and the system was upgraded to Tropical Depression Three, with 35 mph sustained winds and a pressure of 1008 mb just north of eastern Cuba. However, shower activity was primarily displaced to the north and east of the center due to wind shear.

Despite wind shear, a small intensification of the system during the evening of July 22 allowed the system to develop into Tropical Storm Bonnie, with 40 mph sustained winds. Due to an upper level ridge to the system's north, Bonnie accelerated to the westnorthwest during the morning of July 23, reaching a forward speed of 19 mph by 8:00 am EDT that morning. Soon after, the system slammed into Florida with 40 mph winds. Bonnie lost most of its convection before entering the Gulf, and was downgraded to a tropical depression. Despite a redevelopment of convection overnight, the surface pressures continued to rise and the system's center was stripped away by shear, leaving a exposed circulation. Bonnie continued struggling northwestward through the Gulf of Mexico during the morning of July 24, but it ultimately degenerated to a remnant low later that day. The low made landfall in Louisiana on July 25 as it dissipated. Damage was minimal, and one death was recorded in association with this system.



Bonnie after landfall in Florida.



Track of Bonnie.

Tropical Depression Two (2010)

Storm Active: July 7-8
The tropical wave that eventually became Two formed over northeast South America within the ITCZ (Intertropical Convergence Zone). It slowly moved northwestward and as it moved into the western Caribbean, scattered thunderstorm activity began to be associated with it. However, this activity remained disorganized, and the system tracked over the Yucatan Peninsula on July 6. Although the system lost a lot of cloud cover over land, a low pressure center actually developed during this time, allowing the system to be more organized as it emerged into the Gulf of Mexico on July 7. However, the low pressure became elongated over the next few hours, and did not assume the perfect circular shape reminiscent of a healthy circulation. Nevertheless, convection continued to organize, and late that night the system was declared Tropical Depression Two with 35 mph winds and a minimum pressure of 1005 mb.

As had been the trend for a few days, the system lost much of its convection overnight, as it moved towards the Texas-Mexico border at 12 mph, but the circulation remained intact, and even strengthened a little. However, the system did not have enough time to reach tropical storm strength and made landfall in northern Mexico at 11:15 a.m. EST on July 8. The system quickly dissipated over land that evening. Overall, the main effect of Two was flooding, as it hit in an area which had already suffered from Hurricane Alex a few days eariler.



Two at landfall.



Track of Two.