2011 atlantic hurricane season

2011 Atlantic hurricane season

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ContentsArticlesOverview2011 Atlantic hurricane season Timeline of the 2011 Atlantic hurricane season 1 1 21 33 33 41 46 50 57 62 95 100 109 114 118 122 127

Individual hurricanesTropical Storm Arlene Tropical Storm Bret Tropical Storm Don Tropical Storm Emily Tropical Storm Harvey Hurricane Irene Hurricane Katia Tropical Storm Lee Hurricane Maria Tropical Storm Nate Hurricane Ophelia Hurricane Rina Tropical Storm Sean

ReferencesArticle Sources and Contributors Image Sources, Licenses and Contributors 131 133

Article LicensesLicense 136

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Overview2011 Atlantic hurricane season2011 Atlantic hurricane season

Season summary map First storm formed Last storm dissipated Strongest storm Total depressions Total storms Hurricanes June 29, 2011 November 12, 2011 Ophelia 940 mbar (hPa) (27.77 inHg), 140 mph (220 km/h) 20 19 7

Major hurricanes (Cat. 3+) 3 Total fatalities Total damage 120 total > $11.6 billion (2011 USD)

The 2011 Atlantic hurricane season is tied for the third most active season on record with 1887, 1995 and 2010. It began on June 1, 2011, and ended on November 30, 2011, however these dates conventionally delimit the period of each year when most tropical cyclones develop in the Atlantic basin, and if a tropical cyclone formed between November 30 and the end of the year, it would still be counted in the 2011 season.[1] The season began with Arlene, which developed on June 29 in the Gulf of Mexico, and made landfall near Veracruz, causing 25 fatalities, and at least $223 million (2011 USD) in damage. After Arlene, the Atlantic basin featured a series of weak tropical systems, mainly forming off frontal boundaries. Thus, for the first time since reliable records began in 1851, none of the first eight tropical storms attained hurricane strength.[2] This streak ended when Hurricane Irene, the first hurricane and major hurricane of the season, formed in late August. Shortly after Irene, Hurricane Katia became the second major hurricane of the season. Despite the twenty tropical cyclones that have developed in the season, only seven storms became hurricanes (all of them from late August onward), with the last one being Hurricane Rina. There were three tropical cyclones active between September 79, consisting of Katia, Maria, and Nate. It was then

2011 Atlantic hurricane season acknowledged in early September that La Nia had returned, prompting a La Nia Advisory from the Climate Prediction Center.[3] In addition to the eighteen named storms, the National Hurricane Center identified a tropical storm that developed in early September near Bermuda that was not classified operationally.[4]

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Seasonal forecastsPredictions of tropical activity in the 2011 seasonSource Date Named storms 9.6 28 4 Hurricanes Major hurricanes 2.3 8 0

Average (19502000)

[5]

5.9 15 2

Record high activity Record low activity

TSR CSU TSR CSU NOAA TSR UKMO CSU FSU COAPS WSI CSU [15] NOAA WSI December 6, 2010 December 8, 2010 April 4, 2011 April 6, 2011 [7] [8] [9] [10] [11] [6] [5] 1120 17 1018 16 1218 1018 13 16 17 15 16 1419 21 511 9 510 9 610 510 N/A 9 9 8 9 710 7 26 5 25 5 36 25 N/A 5 N/A 4 5 35 4

May 19, 2011 May 24, 2011 May 26, 2011 June 1, 2011 June 1, 2011

[12] [13] [14]

July 26, 2011

August 3, 2011 August 4, 2011 September 21, 2011

19 * Most recent of several such occurrences. (See all) 7 3

Forecasts of hurricane activity are issued before each hurricane season by noted hurricane experts Philip J. Klotzbach, William M. Gray, and their associates at Colorado State University; and separately by NOAA forecasters. Klotzbach's team (formerly led by Gray) defined the average number of storms per season (1950 to 2000) as 9.6tropical storms, 5.9hurricanes, 2.3major hurricanes (storms reaching at least Category3 strength in the Saffir-Simpson Hurricane Scale) and ACE Index 96.1.[16] NOAA defines a season as above-normal, near-normal or below-normal by a combination of the number of named storms, the number reaching hurricane strength, the number reaching major hurricane strength and ACE Index.[17]


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Pre-season forecastsOn December 8, 2010, Klotzbach's CSU team issued its first extended-range forecast for the 2011 season, predicting well above-average activity with 17 named storms, nine hurricanes, and five major hurricanes. In addition, the team expected an accumulated cyclone energy (ACE) value of approximately 165, citing that El Nio conditions were unlikely to develop by the start of the season. Lastly, the team noted a higher chance for storms to make landfall in the United States than in 2010.[5] In addition, Tropical Storm Risk (TSR), a public consortium that comprises experts on insurance, risk management and seasonal climate forecasting at University College London, issued an extended-range forecast a few days prior to that of CSU, with similar estimates for the year. In its report, TSR noted that tropical cyclone activity could be about 40% above the 19502010 average, with 15.6 (4.3) tropical storms, 8.4 (3.0) hurricanes, and 4.0 (1.7) major hurricanes anticipated, and a cumulative ACE index of 141 (58).[6] On April 6, 2011, the CSU team slightly revised their December forecast, predicting 16 named storms, nine hurricanes, and five major hurricanes.[8] On May 19, 2011, the Climate Prediction Center issued NOAA's outlook for the Atlantic hurricane season. The CPC expected that 1218 named storms, 610 hurricanes, and 36 major hurricanes would form in the Atlantic during 2011. The center cited above-normal sea surface temperatures, a weakening La Nia, and the effect of the warm regime of the Atlantic multidecadal oscillation as the basis behind their forecast, adding that seasonal climate models hint that "activity comparable to some of the active seasons since 1995" could occur.[9] On May 26, the UK Met Office (UKMO) issued a forecast of a slightly above-average season. They predicted 13 tropical storms with a 70% chance that the number would be between 10 and 17. However, they do not issue forecasts on the number of hurricanes and major hurricanes. They also predicted an ACE Index of 151 with a 70% chance that the index would be in the range 89 to 212.[11]

Mid-season forecastsOn June 1, CSU released their mid-season predictions, with numbers unchanged from those published in April.[12] Concurrently, the Florida State University Center for Ocean-Atmospheric Prediction Studies (FSU COAPS) issued its third annual Atlantic hurricane season forecast, predicting seventeen named storms, nine hurricanes, and an ACE Index of 163. No prediction for the number of major hurricanes was made.[13]

StormsTropical Storm ArleneTropical storm(SSHS)

Duration Intensity

June 29 July 1 65mph (100km/h) (1-min), 993mbar(hPa)

The origins of Tropical Storm Arlene trace back to a tropical wave that tracked westward across the Caribbean Sea in late June.[18] It proceeded toward the west-northwest along Central America,[19] bringing heavy rainfall to the area that caused flooding and killed three people.[20] [21] By June27, the disturbance had crossed the Yucatn Peninsula and emerged into the Bay of Campeche.[22] [23] Despite moderate wind shear, it organized over warm waters and was

2011 Atlantic hurricane season designated as Tropical Storm Arlene at midnight June29 about 280mi (450km) south-southeast of Tampico, Tamaulipas.[24] As it continued to strengthen, Arlene began to move to the west along a ridge to its north and northwest.[25] Although forecast models supported intensification to hurricane status,[26] the storm attained a peak intensity of only 65mph (100km/h). Arlene moved ashore near Cabo Rojo as a strong tropical storm around 0900UTC June30.[27] Turning west-southwestward, the storm began to weaken as it decreased in organization.[28] On July1, Arlene was downgraded to a tropical depression just before dissipating over the Sierra Madre Mountains;[29] however, rainfall and gusty winds continued to affect portions of Mexico.[30] Arlene's impact resulted in damaging floods and mudslides throughout the country, as well as a total of 22confirmed deaths.[31] Across the state of Hidalgo, damage from the storm reached 2.6billion pesos ($207.4million).[32]

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Tropical Storm BretTropical storm(SSHS)

Duration Intensity

July 17 July 22 65mph (100km/h) (1-min), 996mbar(hPa)

In mid July, a cold front extended westward over the North Atlantic,[33] as its westernmost component remained stationary near Florida.[34] On July 16, a low-pressure area developed to the north of the Bahamas along the weakening boundary;[35] it became better organized under abating shear conditions.[36] A closed circulation center formed, and the next day at 2100 UTC, the NHC issued the formation of Tropical Depression Two about 100mi (160km) northwest of Great Abaco Island.[37] It strengthened into Tropical Storm Bret just three hours after formation.[38] Moving little, Bret continued to strengthen as thunderstorms intensified around the center.[39] The storm developed an eye-like feature on July 18, indicating peak surface winds of around 65mph (100km/h) before it began to accelerate northeastward.[40] Although strong wind shear and dry inhibited further development,[41] Bret maintained a well-defined circulation for the next couple of days, with patches of persistent thunderstorms.[42] However, its center remained exposed, causing it weaken to a tropical depression early on July 22.[43] Despite very hostile wind shear conditions, Bret retained tropical cyclone status for several hours[44] prior to dissipating about 375mi (605km) north of Bermuda.[45]

Tropical Storm Cindy


5

Tropical storm(SSHS)

Duration Intensity


On July17, an area of showers and thunderstorms, associated with the same frontal system that spawned Tropical Storm Bret, consolidated around a developing area of low pressure about 345mi (555km) west-southwest of Bermuda. Tracking east-northeastward, the system gradually organized and became better defined. Passing south of the territory on July19, the disturbance produced moderate rains, peaking at 1.16in (29mm), and gusty winds across the area. On July20, the low developed into a tropical depression east of Bermuda. Embedded within the mid-latitude westerlies, the depression moved northeast and maintained this general direction for the remainder of its existence. Hours later, the system strengthened into Tropical Storm Cindy. Convection steadily increased over the storm and a ragged eye-like featured appeared on both visible and microwave satellite imagery. Corresponding with this, Cindy attained its peak intensity just below hurricane status late on July21 with winds of 70mph (110km/h) and a barometric pressure of 994mbar (hPa; 29.35inHg). Shortly thereafter, the storm moved over waters cooler than 78.8 F (26C). Throughout July22, convection diminished and Cindy transitioned into a post-tropical cyclone about 985mi (1,585km) southwest of Ireland. The remnants persisted for another 12hours before degenerating into a trough over the North Atlantic.[46]

Tropical Storm DonTropical storm(SSHS)

Duration Intensity


Toward the end of July, a persistent westward moving tropical wave showed signs of organization in the Yucatan Channel. A Hurricane Hunters flight observed gale force winds and a broad circulation, which prompted the National Hurricane Center to initiate advisories on Tropical Storm Don on July27.[47] After the storm was named, officials in Texas began making preparations for Don. The University of Texas Medical Branch in Galveston issued a level one alert for Don, and city officials began preparing for a possible evacuation.[48] The NHC later downgraded Don into a tropical depression then a remnant low after it quickly disintegrated upon making landfall and hitting the dry air over Texas as a result of the state's extreme drought, dropping much less than the forecasted rainfall at no more than 2/3 of an inch along the coast.[49]


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Tropical Storm EmilyTropical storm(SSHS)

Duration Intensity

August 1 August 7 50mph (85km/h) (1-min), 1003mbar(hPa)

A strong tropical wave tracked the open Atlantic for several days in late July. The wave remained fairly disorganized, lacking a defined circulation. By July 31, it approached the Lesser Antilles and became better defined, producing inclement weather over much of the area. Late on August 1, it finally developed a closed circulation center, prompting the National Hurricane Center to declare the formation of Tropical Storm Emily just after it had crossed the islands. On August 2, Emily continued to show signs of strengthening, even though most of the convection was off to the south and west of the circulation center. On August 4, Emily weakened into a remnant low but was expected to regenerate at least into a tropical depression. Over the next 2 days, Emily moved over the Bahamas, and up to Florida's southeastern coast, as it slowly strengthened. Later, on August 6, Emily regenerated into a weak depression, dissipating again the next day. The remnants of Emily tracked east-northeastward toward Bermuda. Soon afterwards, Emily's remnants took an eastward turn, and moved towards the open Atlantic. On August 10, convection significantly re-developed in the middle of the Atlantic Ocean, and the National Hurricane Center assessed the system as having a 10% chance of regeneration into a tropical cyclone.[50]

Tropical Storm FranklinTropical storm(SSHS)

Duration Intensity


During the early afternoon of August10, a disorganized area of showers and thunderstorms developed off the east coast of Florida, in association with an elongated area of low pressure.[51] Tracking northeastward in response to deep southeasterly flow,[52] the disturbance slowly organized; however, by the morning of August12, the chances of the system developing into a tropical cyclone remained low.[53] Over the following several hours, marked organization of thunderstorm activity took place around a well-defined low pressure area.[54] Subsequently, the system was classified as Tropical Depression Six that day roughly 260mi (420km) north of Bermuda.[55] Although well to the north of Bermuda, the system brought unsettled weather to the archipelago, with rainfall reaching 0.07in (1.8mm) at L.F. Wade International Airport.[56]

2011 Atlantic hurricane season Maintaining a northeasterly track, the depression intensified into Tropical Storm Franklin early on August13 following a large burst of convection over its center.[57] Later that morning, Franklin attained its peak winds of 45mph (75km/h) before encountering increasing wind shear and decreasing sea surface temperatures.[58] Rapid deterioration of the storm's structure took place as environmental conditions became increasingly hostile for tropical cyclones. Convection was sheared more than 100mi (155km) from the center of circulation and Franklin began acquiring characteristics of an extratropical cyclone.[59] Early on August14, Franklin quickly completed its transition into an extratropical system, prompting the final advisory from the NHC.[60]

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Tropical Storm GertTropical storm(SSHS)

Duration Intensity


During the second week of August, a weak low-pressure area, located east of Bermuda, became associated with a synoptic-scale trough.[61] Dropping west-southwestward, it interacted with an upper low to produce an area of disorganized convection, and by then the NHC began to monitor the system.[62] [63] By August 13, the small low had become very well-defined, with a tight wind circulation center and deep convection; it was designated as a tropical depression at 0300 UTC that day, about 360mi (580km) south-southeast of Bermuda. [64] As the depression re-curved west-northwestward along the weakening subtropical ridge, it intensified into Tropical Storm Gert, due to light wind shear and moist air, about 15 hours after its formation.[65] As Gert neared Bermuda, a small 7 to 9 mi (11 to 14 km) eye-like feature became apparent on radar imagery. Coinciding with this, Gert reached its peak intensity with winds of 65mph (100km/h).[64] Passing roughly 90mi (150km) east of Bermuda, Gert brought light rain and winds up to 25mph (40km/h) to the islands.[56] By August16, convection associated with Gert had mostly dissipated and whether or not the system retained a closed surface low was ambiguous. As a result, Gert degenerated into a post-tropical cyclone over the open Atlantic.[66]

Tropical Storm HarveyTropical storm(SSHS)

Duration Intensity


2011 Atlantic hurricane season In mid-August, a westward moving tropical wave entered the Caribbean Sea. It eventually gained enough organization to be classified as Tropical Depression Eight on August 18. It was upgraded to Tropical Storm Harvey on August 19. By late August 19 the storm was intensifying rapidly and it was announced that it could become a hurricane just before landfall. However, by Saturday afternoon, August 20, Harvey made landfall, never having reached hurricane strength, resetting the Atlantic record as the first eight named storms of the season did not reach hurricane strength. Harvey was then downgraded into a depression though it briefly regained tropical storm status in the Bay of Campeche. It dissipated on August 22.[67]

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Hurricane IreneCategory 3hurricane(SSHS)

Duration Intensity


In the evening of August 20, a large low pressure area became organized enough to be classified as Tropical Storm Irene. It passed over the Leeward Islands early on August 21. Early on August 22, Irene strengthened into a Category 1 hurricane, with winds of 75mph (120km/h) and a central pressure of 987mbar (29.1inHg), becoming the first hurricane of the season. This broke a streak of eight consecutive tropical cyclones to start the 2011 season, all of which did not strengthen beyond tropical storm force. Early on August 24, Irene became a Category 3 major hurricane, with winds of 120mph (150km/h). Irene went through a partial eyewall replacement cycle which weakened it slightly, but caused its wind field to greatly expand. On August 26, New York mayor Michael Bloomberg told coastal residents to 'get moving, now.'[68] The next day, Irene made landfall on Cape Lookout, North Carolina as a category 1 hurricane with 85mph winds and unusually low pressure for a category 1 hurricane. Hurricane Irene made a second U.S. landfall at Little Egg Inlet in New Jersey at 5:35 a.m., making it the first landfalling hurricane in 108 years for New Jersey. On August 28, Irene was downgraded to a tropical storm as it made its third U.S. landfall in the Coney Island area of Brooklyn, New York, at approximately 9:00 a.m. on August 28. Irene became a post-tropical storm over Quebec and Atlantic Canada on August 29.[69] Forming on August 20, Irene was the second earliest ninth Atlantic tropical cyclone on record, along with an unnamed tropical storm from the 1936 season. At least 55 people were confirmed dead across the Caribbean, 10 U.S. states and Canada in the aftermath[70] and damage from Hurricane Irene totaled $10.1billion (2011 USD).[71]

Tropical Depression Ten


9

Tropical depression(SSHS)

Duration Intensity


In late August, a new, well-defined tropical wave moved off the west coast of Africa into the Atlantic Ocean. By August 25, the system had developed sufficient deep convection for the NHC to classify it as Tropical Depression Ten.[72] At this time, the depression attained its peak intensity with winds of 35 mph (55 km/h) and a minimum pressure of 1007 mbar (hPa). Shortly thereafter, wind shear and decreasing sea surface temperatures caused the depression to weaken, degenerating into a remnant low by the evening hours of August 26. [73]

Tropical Storm JoseTropical storm(SSHS)

Duration Intensity


On August 17, a tropical wave exited the west coast of Africa.[74] During the first few days, the tropical wave produced convection, as it slowly moved westward, and became associated with an area of low pressure. But by the next week, the wave dissipated to a weak area of low pressure due to high wind shear as it began to move northwestward, while fluctuating slightly in intensity. In the next few days, the tropical wave approached Bermuda; while remaining disorganized, and weakening even further. Yet very early on August 28 and during the next few hours, the tropical wave partially strengthened as conditions for development slightly improved. However, early on August 28 during the morning hours the tropical wave nearly dissipated due to the high wind shear once again, this time generated by Hurricane Irene, after the tropical wave passed east to the south of Bermuda.[75] But soon afterwards on August 28, the tropical wave managed to develop into Tropical Storm Jose, just to the west of Bermuda; Jose then began to move north-northeast, slowly. It lasted only 27 hours, as it dissipated on August 29.

Hurricane Katia


10

Category 4hurricane(SSHS)

Duration Intensity

August 29 September 10 135mph (215km/h) (1-min), 946mbar(hPa)

The eleventh named storm of the season formed south of the Cape Verde Islands on August 29. The system became a tropical storm on August 30, at which time it was named Katia. It became the season's second hurricane early on September 1; however, its strength fluctuated until September 4 when it reached category 2 hurricane strength. On September 5 the system reached Category 3 (major hurricane status). Katia further strengthened into a Category 4 hurricane on September 5. It was downgraded to a category 1 storm by the end of the following day, and remained at that strength even as it became extra-tropical. The storm was of potential concern and was being monitored closely as it may have indirectly impacted the east coast of the United States and Canada. Warnings of severe weather were made for Northern Ireland and Scotland for the remnants of Katia.[76] Its remnants struck the UK and the Republic of Ireland on September 11 and September 12, killing one. Its remnants caused blackouts as far east as Saint Petersburg.

Unnamed Tropical StormTropical storm(SSHS)

Duration Intensity

September 1 September 2 45mph (75km/h) (1-min), 1002mbar(hPa)

As part of their routine post-season analysis, the National Hurricane Center identified an Unnamed Tropical Storm that formed near 0000 UTC September 1 roughly 290mi (470km) north of Bermuda. On August 31, a disturbance formed north of Bermuda, and the NHC classified it as Invest 94L, as they tracked the storm. On September 1, the storm organized into a tropical depression, very early that morning. Despite being embedded within an environment of moderate wind shear, the depression quickly intensified into a tropical storm, although it was not assigned a name, because it was not recognized operationally. The system reached a peak intensity of 45mph (75km/h) early on September 2, prior to its transition into an extratropical cyclone later that day. However, the extratropical remnant of the system continued to move east-northeast, and later eastward, as it slowly weakened. On September 4, at about 0000 UTC, the extratropical remnant of the unnamed tropical storm dissipated, to a weak surface trough.[77]


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Tropical Storm LeeTropical storm(SSHS)

Duration Intensity


In late August, a tropical wave producing scattered showers and thunderstorms entered the Western Caribbean.[78] Moving generally west-northwestward, the wave began to organize in the southeastern portion of the Gulf of Mexico. During the afternoon hours of September 1, the hurricane hunters went out to investigate the well-defined wave, and found a closed low-level circulation. Thus, advisories were initiated on Tropical Depression Thirteen.[79] Moving northwest, the tropical depression was upgraded to a tropical storm, given the name "Lee" on September 2.[80] Continuing to organize, Lee reached a peak intensity of 60mph (95km/h) early on September 3, while located just south of Louisiana. At 4 a.m. CDT September 4, Lee made landfall roughly 50 miles (80km) to the southwest of Lafayette, Louisiana with maximum sustained winds of 45mph (75km/h).[81] Further weakening occurred as Lee moved across Louisiana, and the last NHC advisory on Lee was issued early on September 5, while its remnants proceeded to wreak havoc (mainly flooding) over the following two to three days northward into Pennsylvania, New York State and Canada (Quebec and Ontario).[82]

Hurricane MariaCategory 1hurricane(SSHS)

Duration Intensity


On September 5, a low pressure area associated with a tropical wave to the west of Africa quickly organized.[83] It was designated Tropical Depression Fourteen on the evening of September 6.[84] On the morning of September 7, it was upgraded to Tropical Storm Maria.[85] Over the tropical Atlantic, high wind shear hindered its development, and Maria nearly dissipated, before convection began to rebuild by September 9. The following day, it began to encounter more favorable conditions, and the tropical cyclone intensified into a Category 1 hurricane on September 15. On the afternoon of September 16, the storm lost tropical characteristics off the northeast coast of Newfoundland. Landfall was reported on the southern tip of the Avalon Peninsula with winds recorded at 64mph (103km/h). The capital city of St. John's experienced heavy rain and gale-force winds, but not as severe as anticipated.[86]


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Hurricane NateCategory 1hurricane(SSHS)

Duration Intensity


During the morning hours of September 6, shower and thunderstorm activity associated with a low pressure system began to gather organization in the Bay of Campeche.[87] The following day, the system gained enough organization to be classified as a tropical storm, earning the name Nate.[88] Moving in an erratic motion at a very slow pace, Nate began to strengthen. During the afternoon hours of September 8, Nate reached its peak intensity of 75mph (120km/h), while moving off towards the Mexican coastline. The storm was originally thought to remain a tropical storm, but post-season analysis revealed that Nate was a hurricane for twelve hours based on data from PEMEX oil rigs not available operationally.[89] Due to the storm's slow movement, Nate began to upwell cooler waters in its wake, resulting in weakening. Additionally, very dry air began getting entrained into the system. On September 11, Nate made landfall on the Mexican coastline as a weak tropical storm, with maximum sustained winds of 45mph (75km/h).[90] Shortly after making landfall, much of Nate's showers and thunderstorms dissipated, and thus rainfall totals were minimal.[89]

Hurricane OpheliaCategory 4hurricane(SSHS)

Duration Intensity

September 21 October 3 140mph (220km/h) (1-min), 940mbar(hPa)

In mid-September, a well-defined tropical wave emerged off the African coastline. Moving westward, the disturbance began to gather organization, and become very well defined on September20. Subsequently, the National Hurricane Center started issuing advisories on Tropical Storm Ophelia. Almost as soon as it became a tropical storm, vertical wind shear began impacting the system. Ophelia slowly strengthened despite the unfavorable conditions and attained winds of 65mph (100km/h) on September22. The system briefly weakened to a minimal tropical storm before strengthening again. However, because of the extremely strong wind shear, Ophelia was ripped apart and dissipated into a post-tropical remnant low on September25. Wind shear remained strong, but not as strong as before. Thus, during the afternoon hours of September27, Ophelia was able to develop convection near its center, and was designated a tropical depression. Ophelia gradually

2011 Atlantic hurricane season strengthened further into a tropical storm as it passed to the north of the Caribbean. In Dominica, heavy rains from the storm caused widespread flooding. During the afternoon hours of September29, despite the relatively unfavorable environment, Ophelia strengthened into a Category1 hurricane. As wind shear relaxed, early on September30, Ophelia rapidly intensified and became a Category2 hurricane. Later that day, Ophelia further strengthened into a Category3 hurricane, becoming the third major hurricane of the season. The eye of Ophelia passed directly over a NOAA buoy early on October1, which reported sustained winds of 96mph (155km/h) and a pressure of 952mbar (28.11inHg). The intensification trend continued, and Ophelia strengthened further to a Category4 hurricane late that day east of Bermuda. Through the following day (Sunday), increasing southwesterly wind shear and cooler water temperatures combined to cause Ophelia to progressively weaken back into a Category1 hurricane by evening and weakened to a tropical storm during the morning hours of October 3. Several hours later, Ophelia was declared as a post-tropical cyclone soon after making landfall on the Avalon Peninsula in Newfoundland.

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Hurricane PhilippeCategory 1hurricane(SSHS)

Duration Intensity

September 24 October 9 90mph (150km/h) (1-min), 976mbar(hPa)

On September 23, a well-defined tropical wave emerged off the coast of Africa, associated with plentiful shower and thunderstorm activity.[91] Moving westward and embedded within a favorable environment for development, the wave quickly became organized. During the morning hours of September 24, the National Hurricane Center designated the low as a tropical depression, while located about 290mi (465km) south of the southernmost Cape Verde Islands.[92] Later that day, the depression was upgraded to a tropical storm, designated "Philippe". Since that time strong shear from both upper level winds and later on from Ophelia's outflow, as well as periodic entrainment of dry air kept the cyclone both small and disorganized, with the center often exposed to the point where the low level circulation reformed under the convection that defines a tropical system at least once. An exposed cyclone can be seen as a wispy series of clouds circling a small area, rather than under the canopy of thunderstorms. Because of this hostile environment, Philippe remained near the minimum for a tropical storm. On the afternoon of October 2, an Advanced Scatterometer (ASCAT) pass confirmed that Philippe was a strong tropical storm, contrary to satellite estimates. Despite high wind shear, it remained a strong tropical storm afterward and actually at times developed an eye feature. On October 6, after over 12 days as a tropical storm, Philippe became a strong Category 1 hurricane. On October 8, Philippe weakened to a tropical storm, then became post-tropical hours later, on October 9.


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Hurricane RinaCategory 2hurricane(SSHS)

Duration Intensity

October 23 October 28 110mph (175km/h) (1-min), 966mbar(hPa)

In mid-October, the southern extension of a cold front moved into the western Caribbean. The front, in conjunction with east-southeasterly trade winds, produced a broad area of cyclonic circulation over the southwestern Caribbean. [93] Moving slowly towards the north and northwest, barometric pressures in the area began falling, and the disturbance was expected to move into an environment more conducive for development. Thus, the National Hurricane Center gave the disturbance a medium chance, 30%, of developing into a tropical cyclone within 48 hours. [94] Further organization occurred during the afternoon hours of October 21, as the low pressure area became more consolidated. [95] However, the following day, the disturbance became slightly less organized, depicted by a decrease in tropical cyclone formation probabilities. [96] On October 23, a reconnaissance aircraft flew into the disturbance, finding a well-defined center of circulation. This, combined with satellite imagery, led to the formation of Tropical Depression Eighteen during the evening hours of that day; it strengthened to a tropical storm just several hours later, and earned the name "Rina".[97] Moving towards the north-northwest, Rina rapidly intensified on October 24, becoming a hurricane just 21 hours after formation. Further strengthening commenced for the remaining of the day, although Rina did not reach peak intensity until the evening hours of October 25. Shortly thereafter, the increase of wind shear and dry air led to weakening the following day, and Rina weakened to a tropical storm early on October 27. Scraping the Yucatan Peninsula, Rina brought heavy rainfall and gusty winds before turning towards the north. Early the next day, Rina weakened into a tropical depression, and during the afternoon hours, further dissipated into a remnant low.

Tropical Storm SeanTropical storm(SSHS)

Duration Intensity

November 8 November 12 65mph (100km/h) (1-min), 983mbar(hPa)

During the mid-afternoon of November 4, the non-tropical cyclone that would later become Tropical Storm Sean, emerged off the extreme southern coast of North Carolina.[98] On November 6, the National Hurricane Center began monitoring a non-tropical area of low pressure producing a large area of gale force winds to the southwest of Bermuda. Moving towards the south and southeast, the low pressure area began to enter higher Sea Surface

2011 Atlantic hurricane season Temperatures and subsequently became better organized. By the early morning hours of November 8, the low had become sufficiently organized to be declared as a subtropical storm, and then a fully tropical storm several hours later. Sean strengthened to attain a peak intensity of 65mph (100km/h) on November 9 and 10 before it began to enter an area of higher wind shear. Early on November 12, Sean was absorbed by a cold front, associated with a powerful extratropical cyclone centered over Newfoundland, while Sean was located several hundred miles to the northeast of Bermuda.[99]

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Storm namesThe following names were used for named storms in the North Atlantic in 2011. Names that were not used are marked in gray. This is the same list used in the 2005 season with the exception of Don, Katia, Rina, Sean, and Whitney, which replaced Dennis, Katrina, Rita, Stan, and Wilma, respectively. The names Don, Katia, Rina, and Sean were used for the first time in the Atlantic Basin.[100] Retired names, if any, will be announced by the World Meteorological Organization in the spring of 2012. The names not retired from this list will be used again in the 2017 season. Arlene Bret Cindy Don Emily Gert Harvey Irene Jose Katia Lee Maria Nate Ophelia Philippe Rina Sean Tammy(unused) Vince(unused) Whitney(unused)

Franklin

Season effectsThis is a table of all of the storms that have formed in the 2011 Atlantic hurricane season. It includes their duration, names, landfall(s) denoted by bold location names damages, and death totals. Deaths in parentheses are additional and indirect (an example of an indirect death would be a traffic accident), but were still related to that storm. Damage and deaths include totals while the storm was extratropical, a wave, or a low, and all of the damage figures are in 2011 USD.SaffirSimpson Hurricane Scale TD TS C1 C2 C3 C4 C5

2011 North Atlantic tropical cyclone statisticsStorm name Dates active Storm category at peak intensity Max Min. 1-min press. wind (mbar) mph (km/h) 65 (100) 65 (100) 70 (110) 50 (85) Areas affected Damage Deaths (millions USD)

Arlene

June29 July1

Tropicalstorm

993 Central America, Yucatan Peninsula, Florida, Mexico (Veracruz), Texas 996 Florida, The Bahamas, Bermuda

223.4

25

Bret

July17 July22 July20 July23 July27 July30

Tropicalstorm

None

0

Cindy

Tropicalstorm

994 Bermuda

None

0

Don

Tropicalstorm

997 Lesser Antilles, Greater Antilles, Yucatan Peninsula, South Texas, Northeastern Mexico

None

0


16Tropicalstorm 50 (85) 1003 Lesser Antilles, Puerto Rico, Hispaniola, Turks and Caicos Islands, Eastern Cuba, The Bahamas, South Florida 1004 Bermuda >5 5

Emily

August1 August7

Franklin

August 12 August13 August 14 August16 August 18 August22 August 20 August29

Tropicalstorm

45 (75)

None

0

Gert

Tropicalstorm

65 (100) 65 (95)

1000 Bermuda

None

0

Harvey

Tropicalstorm

994 Lesser Antilles, Honduras, Belize, Guatemala, Mexico (Veracruz) 942 Leeward Islands, Puerto Rico, Hispaniola, Turks and Caicos Islands, The Bahamas, Eastern Cuba, Southeastern United States (Outer Banks), Mid-Atlantic states (New Jersey, New York), New England, Eastern Canada 1007 None

Minimal

3

Irene

Category3hurricane

120 (140)

>10,100

56

Ten

August 25 August27 August 28 August29 August 29 September 10

Tropicaldepression

35 (55)

None

0

Jose

Tropicalstorm

45 (75)

1007 Bermuda

None

0

Katia

Category4hurricane

135 (215)

946 Leeward Islands, Bahamas, United States East Coast, Bermuda, Atlantic Canada, Ireland, United Kingdom, Scandinavia, Russia 1002 None

~157

4

Unnamed

September 1 September 2

Tropicalstorm

45 (75)

None

0

Lee

September 1 September 5 September 6 September 16 September 7 September 11 September 21October 3 September 24October 9 October 23October 28 November 8November 12

Tropicalstorm

60 (95)

986 Southern United States (Louisiana), Northeastern United States 979 Lesser Antilles, Bermuda, Newfoundland

>1,000

21

Maria

Category1hurricane

80 (130) 75 (120) 140 (220) 90 (150) 110 (175) 65 (100)

N/A

0

Nate

Category1hurricane

994 Mexico (Veracruz)

Minimal

5

Ophelia

Category4hurricane

940 Leeward Islands, Bermuda, Newfoundland, Ireland, United Kingdom 976 None

N/A

0

Philippe

Category1hurricane

None

0

Rina

Category2hurricane

966 Honduras, Nicaragua, Yucatn Peninsula (Quintana Roo) 983 Bermuda

N/A

0

Sean

Tropicalstorm

None

1

Season Aggregates 20 cyclones June29 November12 140 (220) 940 >11,633.2 120


17

Accumulated Cyclone Energy (ACE)ACE (104kt) (Source) Storm: 1 2 3 4 5 6 7 8 9 24.8 Katia 20.3 Irene 18.4 Ophelia 14.8 Philippe 9.07 Rina 8.74 Maria 3.83 Nate 3.33 Sean 2.95 Bret 11 12 13 14 15 16 1.99 1.85 1.71 1.63 1.62 1.53 Emily Gert Lee Arlene Don Harvey

17 0.848 Unnamed 18 0.528 Jose 19 0.283 Franklin

10 2.31 Cindy Total: 121

The table on the right shows the ACE for each storm in the season. Broadly speaking, the ACE is a measure of the power of a hurricane multiplied by the length of time it existed, so storms that last a long time, as well as particularly strong hurricanes, have high ACEs. ACE is calculated for only full advisories on specifically tropical systems reaching or exceeding wind speeds of 34knots (39mph, 63km/h), or tropical storm strength. Accordingly, tropical depressions are not included here. The ACE also does not include subtropical storms, therefore values accrued while Sean was subtropical are not calculated in its ACE. Later the NHC reexamines the data, and produces a final report on each storm, which can lead to the ACE for a storm being revised either upward or downward. Until the final reports are issued, ACEs are, therefore, provisional.

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18

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19

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"NHC Graphical Tropical Weather Outlook" (http:/ / www. nhc. noaa. gov/ archive/ gtwo/ atl/ 201109231142/ index. php?basin=atl& current_issuance=201109231142). National Hurricane Center. . Retrieved 24 September 2011. [92] Blake, Eric. "Tropical Depression Seventeen Public Advisory #1" (http:/ / www. nhc. noaa. gov/ text/ refresh/ MIATCPAT2+ shtml/ 240858. shtml?). National Hurricane Center. . Retrieved 24 September 2011. [93] Garcia, Felix. "Tropical Weather Discussion" (http:/ / www. nhc. noaa. gov/ archive/ text/ TWDAT/ 2011/ TWDAT. 201110201746. txt). National Hurricane Center. . Retrieved 28 October 2011. [94] Avila, Blake, Lixion, Eric. "Graphical Tropical Weather Outlook" (http:/ / www. nhc. noaa. gov/ archive/ gtwo/ atl/ 201110211146/ index. php?basin=atl& current_issuance=201110211146). National Hurricane Center. . Retrieved 28 October 2011.

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2011 Atlantic hurricane season[95] Kimberlain, Todd. "Graphical Tropical Weather Outlook" (http:/ / www. nhc. noaa. gov/ archive/ gtwo/ atl/ 201110212350/ index. php?basin=atl& current_issuance=201110212350). National Hurricane Center. . Retrieved 28 October 2011. [96] Avila, Lixion. "Graphical Tropical Weather Oulook" (http:/ / www. nhc. noaa. gov/ archive/ gtwo/ atl/ 201110221737/ index. php?basin=atl& current_issuance=201110221737). National Hurricane Center. . Retrieved 28 October 2011. [97] Brown, Daniel. "Tropical Depression Eighteen" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al18/ al182011. public. 001. shtml?). National Hurricane Center. . Retrieved 28 October 2011. [98] http:/ / www. nhc. noaa. gov/ archive/ gtwo/ atl/ 201111041746/ index. php?basin=atl& current_issuance=201111041746 [99] http:/ / www. nhc. noaa. gov/ archive/ gtwo/ atl/ 201111121156/ index. php?basin=atl& current_issuance=201111121156 [100] "Retired Hurricane Names Since 1954" (http:/ / www. nhc. noaa. gov/ retirednames. shtml). National Hurricane Center. . Retrieved 29 November 2009.

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External links HPC rainfall page for 2011 Tropical Cyclones (http://www.hpc.ncep.noaa.gov/tropical/rain/2011.html) National Hurricane Center Website (http://www.nhc.noaa.gov) National Hurricane Center's Atlantic Tropical Weather Outlook (http://www.nhc.noaa.gov/text/MIATWOAT. shtml) Tropical Cyclone Formation Probability Guidance Product (http://www.ssd.noaa.gov/PS/TROP/TCFP/ atlantic.html)

Timeline of the 2011 Atlantic hurricane seasonThe 2011 Atlantic hurricane season was an above-average Atlantic hurricane season, with a total of nineteen named storms throughout the Gulf of Mexico, Caribbean, and Atlantic basin. The season officially began on June 1 and ended on November 30,[1] with the season's first storm, Tropical Storm Arlene developing on June 29.[2] The season has had twenty tropical depressions, of which nineteen have intensified into tropical storms, seven have become hurricanes, and out of those seven, three have become major hurricanes. The Track of all the storms that formed during 2011. increased activity so far this season can be linked to La Nia, which provides a favorable environment for tropical systems to develop, but the amount of dry air around the basin became fault to why there has been only six hurricanes. The most significant system of the season was Hurricane Irene, the first hurricane to make landfall in the United States since Hurricane Ike in the 2008 season. The storm caused significant flooding in the Northeast United States, an area already plagued with record rainfall totals. The storm killed at least 56 people, and has caused over $10.1 billion in damage. Another landfalling tropical cyclone the season had was Tropical Storm Lee, which made landfall on the coast of Louisiana, also causing heavy rainfall in the Northeast. For this reason, the storm has killed at least 21, spawned more than 20 tornadoes and caused over $1 billion in damage. This timeline includes information that was not operationally released, meaning that information from post-storm reviews by the National Hurricane Center, such as a storm that was not operationally warned upon, has been included. This timeline documents tropical cyclone formations, strengthening, weakening, landfalls, extratropical transitions, and dissipations during the season.

Timeline of the 2011 Atlantic hurricane season

22

Timeline of events

JuneJune 1 The 2011 Atlantic hurricane season officially begins.[1] June 29 0000 UTC (7 p.m. CDT June 28) Tropical Storm Arlene, the first storm of the season, forms about 280mi (450km) south-southeast of Tampico, Mexico.[3] June 30 0900 UTC (4 a.m. CDT) Tropical Storm Arlene makes landfall near Cabo Rojo, Veracruz with 65mph (100km/h) winds.[4]

JulyJuly 1

Arlene making landfall near Cabo Rojo, Veracruz.

0000 UTC (7 p.m. CDT June 30) Tropical Storm Arlene weakens to a tropical depression.[5] 0300 UTC (10 p.m. CDT June 30) Tropical Depression Arlene dissipates over the high terrain of Mexico.[6] July 17 2100 UTC (5 p.m. EDT) Tropical Depression Two forms about 100 miles (165km) northwest of Great Abaco Island.[7] July 18 0000 UTC (8 p.m. EDT July 17) Tropical Depression Two strengthens into Tropical Storm Bret.[8] July 20 0600 UTC (2 a.m. AST) Tropical Depression Three forms from an area of low pressure roughly 305 miles (491km) east of Bermuda.[9] 1200 UTC (8 a.m. AST)- Tropical Depression Three strengthens into Tropical Storm Cindy.[9] July 21 1800 UTC (2 p.m. AST) Tropical Storm Cindy attains its peak intensity with maximum sustained winds of 70mph (110km/h) and a minimum barometric pressure of 994mbar (29.4 inHg).[9] July 22 0300 UTC (11 p.m. AST July 21) Tropical Storm Bret weakens to a tropical depression.[10] 1500 UTC (11 a.m. AST) Tropical Depression Bret degenerates into a remnant low.[11] July 23 0000 UTC (8 p.m. AST) Tropical Storm Cindy degenerates into a remnant low.[9] July 27Track map of Tropical Storm Bret.

Timeline of the 2011 Atlantic hurricane season 0600 UTC (1 a.m. CDT) Tropical Depression Four develops about 58 miles (93km) northeast of Cancn, Mexico.[12] 1800 UTC (1 p.m. CDT) Tropical Depression Four strengthens into Tropical Storm Don.[12] July 29 0000 UTC (7 p.m. CDT July 28) Tropical Storm Don attains its peak intensity with maximum sustained winds of 50mph (85km/h) and a minimum pressure of 997mbar (29.4inHg).[12] July 30 0230 UTC (10:30 p.m. CDT July 28) Tropical Storm Don weakens to a tropical depression. Simultaneously, Don made landfall near Baffin Bay, Texas with winds of 35mph (55km/h).[12] 0600 UTC (1 a.m. CDT) Tropical Depression Don degenerates into a remnant low over Texas.[12]

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AugustAugust 1 2330 UTC (7:30 p.m. AST) Tropical Storm Emily forms about 50 miles (85km) west-southwest of Dominica.[13] August 4 2100 UTC (5 p.m. AST) Tropical Storm Emily degenerates into a remnant low.[14] August 6 2100 UTC (5 p.m. EDT) Tropical Depression Emily regenerates about 70 miles (115km) west-northwest of Great Abaco Island.[15]Emily near Hispaniola on August 3.

August 7 2100 UTC (5 p.m. EDT) Tropical Depression Emily dissipates.[16] August 12 1800 UTC (2 p.m. AST) Tropical Depression Six forms about 230 miles (370km) north of Bermuda.[17] August 13 0600 UTC (2 a.m. AST) Tropical Depression Six strengthens into Tropical Storm Franklin.[17] 1200 UTC (8 a.m. AST) Tropical Storm Franklin attained its peak intensity with maximum sustained winds of 45 mph (75 km/h) and a minimum pressure of 1004 mbar (hPa; 29.65 inHg).[17] 1800 UTC (2 p.m. AST) Tropical Depression Seven forms about 425 miles (684km) southeast of Bermuda.[18] 1800 UTC (2 p.m. AST) Tropical Storm Franklin transitions into an extratropical low.[17]


24

August 14 0600 UTC (2 a.m. AST) Tropical Depression Seven strengthens into Tropical Storm Gert.[18] August 15 1200 UTC (8 a.m. AST) Tropical Storm Gert attained its peak intensity with maximum sustained winds of 65 mph (100 km/h) and a minimum pressure of 1000mbar (30inHg).[18] August 16 1200 UTC (8 a.m. EDT) Tropical Storm Gert degenerates into an extratropical low.[18] August 19Tropical Storm Gert over the open Atlantic.

0000 UTC (8 p.m. EDT August 18) Tropical Depression Eight forms about 80 miles (130km) northeast of Cabo Gracias a Dios.[19] 1200 UTC (8 p.m. EDT) Tropical Depression Eight strengthens into Tropical Storm Harvey.[19] August 20 0600 UTC (2 a.m. EDT) Tropical Storm Harvey attained its minimum pressure of 994mbar (29.4inHg).[19] 1730 UTC (12:30 p.m. CDT) Tropical Storm Harvey attained its maximum sustained winds of 60 mph (95 km/h) while making landfall near Dangriga, Belize.[19] 2300 UTC (7 p.m. AST) Tropical Storm Irene forms about 190 miles (305km) east of Dominica.[20] August 21 0600 UTC (1 a.m. CDT) Tropical Storm Harvey weakens to a tropical depression.[19] August 22 0000 UTC (7 p.m. CDT August 21) Tropical Depression Harvey re-strengthens into a tropical storm.[19] 0200 UTC (9 p.m. CDT August 21) Tropical Storm Harvey made landfall near Punta Roca Partida, Mexico with winds of 40 mph (65 km/h).[19] 0530 UTC (1:30 a.m. AST) Tropical Storm Irene makes landfall near Punta Santiago, Puerto Rico.[21] 0600 UTC (1 a.m. CDT) Tropical Storm Harvey weakens to a tropical depression.[19] 0900 UTC (5 a.m. AST) Tropical Storm Irene strengthens into a Category1 hurricane.[22] August 23 0000 UTC (8 p.m. AST August 22) Hurricane Irene strengthens into a Category2 hurricane.[23] 2100 UTC (5 p.m. AST) Hurricane Irene weakens back to a Category1 hurricane.[24] August 24 0600 UTC (2 a.m. AST) Hurricane Irene restrengthens into a Category 2 hurricane.[25] 1200 UTC (8 a.m. AST) Hurricane Irene strengthens into a Category 3 hurricane.[26] August 25Irene shortly after becoming a hurricane.

1800 UTC (1 p.m. CDT) Tropical Depression Harvey dissipated over Puebla.[19]

Timeline of the 2011 Atlantic hurricane season 0900 UTC (5 a.m. AST) Tropical Depression Ten forms about 435 miles (700km) west-southwest of the southernmost Cape Verde Islands.[27] August 26 0900 UTC (5 a.m. EDT) Hurricane Irene weakens back to a Category 2 hurricane.[28] August 27 0300 UTC (11 p.m. AST August 26) Tropical Depression Ten dissipates 645 miles (1,040km) west of the southernmost Cape Verde Islands.[29] 0700 UTC (3 a.m. EDT) Hurricane Irene weakens back to a Category 1 hurricane.[30] 1130 UTC (7:30 a.m. EDT) Hurricane Irene makes its first US landfall near Cape Lookout, North Carolina with winds of 85mph (140km/h).[31] August 28 0935 UTC (5:35 a.m. EDT) Hurricane Irene makes landfall near Little Egg Harbor Inlet, New Jersey with winds of 75mph (120km/h).[32] 1200 UTC (8 a.m. EDT) Tropical Storm Jose forms 115 miles (185km) south-southwest of Bermuda.[33] 0300 UTC (11 p.m EDT) Tropical Storm Irene transitions into an extratropical storm.[34] August 29 0500 UTC (1 a.m. AST) Tropical Depression Twelve forms 395 miles (635km) south-southwest of Cape Verde.[35] 1700 UTC (11 a.m EDT) Tropical Storm Jose dissipates.[36] August 30 0600 UTC (2 a.m AST) Tropical Depression Twelve strengthens into Tropical Storm Katia.[37]Track map of Tropical Depression Ten.

25

SeptemberSeptember 1 0000 UTC (8 p.m. EDT August 31) A tropical depression developed about 335 miles (539km) to the north of Bermuda.[38] 0300 UTC (11 p.m. EDT August 31) Tropical Storm Katia strengthens into a Category 1 hurricane.[39] 1200 UTC (8 a.m. EDT) The tropical depression intensified into an unnamed tropical storm.[38] 2100 UTC (5 p.m. EDT) Hurricane Katia weakens to a tropical storm.[40] September 2Hurricane Katia as a Category 2 hurricane.

0000 UTC (7 p.m. CDT September 1) Tropical Depression Thirteen forms about 225 miles (362km) southwest of the mouth of the Mississippi River.[41] 0600 UTC (2 a.m. EDT) The unnamed tropical storm attained its peak intensity with maximum winds of 45 mph (75 km/h) and a minimum pressure of 1002mbar (29.6inHg).[38] 1500 UTC (11 a.m. EDT) Tropical Storm Katia re-strengthens into a Category 1 hurricane.[42] 1800 UTC (1 p.m. CDT) Tropical Depression Thirteen strengthens into Tropical Storm Lee.[43] September 3

Timeline of the 2011 Atlantic hurricane season 0000 UTC (8 p.m. EDT September 2) The unnamed tropical storm transitioned into an extratropical cyclone while centered about 357 miles (575km) south-southeast of Halifax, Nova Scotia.[38] 2100 UTC (5 p.m. EDT) Hurricane Katia weakens to a tropical storm.[44] September 4 0900 UTC (4 a.m. CDT) Tropical Storm Lee makes landfall southwest of Intracoastal City, Louisiana with 45mph (75km/h) winds.[45] 1100 UTC (7 a.m. AST) Tropical Storm Katia re-strengthens into a Category 1 hurricane.[46] 1500 UTC (11 a.m. EDT) Hurricane Katia strengthens into a Category 2 hurricane.[47] September 5 0300 UTC (10 p.m. CDT September 4) Tropical Storm Lee weakens into a tropical depression.[48] 0900 UTC (4 a.m. CDT) Tropical Depression Lee transitions into an extratropical cyclone as it merged with a frontal zone while centered over Louisiana.[49] 2100 UTC (5 p.m. AST) Hurricane Katia strengthens into a Category 3 hurricane.[50] September 6 0300 UTC (11 p.m. AST September 5) Hurricane Katia strengthens into a Category 4 hurricane.[51] 0900 UTC (2 a.m. AST) Hurricane Katia weakens to a Category 3 hurricane. 2100 UTC (5 p.m. AST) Hurricane Katia weakens to a Category 2 hurricane. 2100 UTC (5 p.m. AST) Tropical Depression Fourteen forms about 920 miles (1480km) west-southwest of the Cape Verde Islands.[52] September 7 0900 UTC (5 a.m. AST) Hurricane Katia weakens to a Category 1 hurricane.[53] 1500 UTC (11 a.m. AST) Tropical Depression Fourteen strengthens into Tropical Storm Maria.[54] 1800 UTC (1 p.m. CDT) Tropical Storm Nate forms about 160 miles (260km) north of Villahermosa, Tabasco, Mexico.[55]

26

Tropical Storm Lee near landfall.


27

September 8 1800 UTC (1 p.m. CDT) Tropical Storm Nate strengthens into a Category 1 hurricane.[55] September 9 0000 UTC (7 p.m. CDT September 8) Hurricane Nate attained its peak intensity with winds of 75mph (120km/h) and a minimum pressure of 994mbar (hPa; 29.35inHg).[55] 0600 UTC (1 a.m. CDT) Hurricane Nate weakens to a tropical storm.[55] September 10 1500 UTC (11 a.m. AST) Hurricane Katia becomes post-tropical.[56] September 11 1600 UTC (11 a.m. CDT) Tropical Storm Nate made landfall near Tecolutla, Veracruz with winds of 45mph (75km/h).[55] September 12 0600 UTC (1 a.m. CDT) Tropical Storm Nate degenerates into a remnant low.[55] September 15 2100 UTC (5 p.m. AST) Tropical Storm Maria strengthens into a Category 1 hurricane.[57] September 16 1830 UTC (2:30 p.m. AST) Hurricane Maria makes landfall near Cape Pine, Newfoundland with winds of 75mph (120km/h).[58] 2100 UTC (5 p.m. AST) Hurricane Maria becomes post-tropical.[59] September 21 0300 UTC (11 p.m. EDT September 20) Tropical Storm Ophelia forms about 1585 miles (2555 km) east-southeast of the Leeward Islands. [60] September 24 0900 UTC (5 a.m. AST September 24) Tropical Depression Seventeen forms about forms about 290 mi (465 km) south of the southernmost Cape Verde Islands.[61] 2100 UTC (5 p.m. AST) Tropical Depression Seventeen strengthens into Tropical Storm Philippe.[62]Maria on September 15.


28

September 25 2100 UTC (5 p.m. AST) Tropical Storm Ophelia degenerates into a remnant low.[63] September 27 2100 UTC (5 p.m. AST) Remnants of Ophelia regenerate into a tropical depression about 175miles (285km) east-southeast of the northern Leeward Islands.[64] September 28 1500 UTC (11 a.m. AST) Tropical Depression Ophelia strengthens into a tropical storm.[65] September 29 2100 UTC (5 p.m. AST) Tropical Storm Ophelia strengthens into a Category 1 hurricane.[66] September 30 0900 UTC (5 a.m. AST) Hurricane Ophelia strengthens into a Category 2 hurricane.[67]Hurricane Ophelia as a major hurricane.

1500 UTC (11 a.m. AST) Hurricane Ophelia strengthens into a Category 3 hurricane.[68]

OctoberOctober 1 0000 UTC (5 p.m. AST October 1) Hurricane Ophelia strengthens into a Category 4 hurricane.[69] October 2 0900 UTC (5 a.m. AST) Hurricane Ophelia weakens into a Category 3 hurricane.[70] 1500 UTC (11 a.m. AST) Hurricane Ophelia weakens weakens into a Category 2 hurricane.[71] October 3 0000 UTC (8 p.m. AST October 2) Hurricane Ophelia weakens weakens into a Category 1 hurricane.[72] 0900 UTC (5 a.m. AST) Hurricane Ophelia weakens weakens into a tropical storm.[73] 1500 UTC (11 a.m. AST) Tropical Storm Ophelia becomes post-tropical.[74] October 6 1500 UTC (11 a.m. AST) Tropical Storm Philippe strengthens into a Category 1 hurricane.[75] October 7 2100 UTC (5:00 p.m. AST) Hurricane Philippe weakens into a tropical storm.[76] October 8 0300 UTC (11:00 p.m. AST) Tropical Storm Philippe becomes post-tropical.[77] October 23 2100 UTC (5:00 p.m. EDT) Tropical Depression Eighteen forms 105 miles (169km) northeast of Cabo Gracias a Dios, Honduras.[78]Track map of Hurricane Philippe.

Timeline of the 2011 Atlantic hurricane season October 24 0300 UTC (11:00 p.m. EDT October 23) Tropical Depression Eighteen strengthens into Tropical Storm Rina.[79] 1800 UTC (2:00 p.m. EDT) Tropical Storm Rina strengthens into a Category 1 hurricane.[80] October 25 0900 UTC (5:00 a.m. EDT) Hurricane Rina strengthens into a Category 2 hurricane.[81] October 26 1645 UTC (11:45 a.m. CDT) Hurricane Rina weakens into a Category 1 hurricane.[82]Hurricane Rina at peak intensity.

29

October 27 1500 UTC (10:00 a.m. CDT) Hurricane Rina weakens into a tropical storm.[83] October 28 1500 UTC (10:00 a.m. CDT) Tropical Storm Rina weakens into a tropical depression.[84] 2100 UTC (4:00 p.m. CDT) Tropical Depression Rina dissipates into a remnant low.[85]

NovemberNovember 8 0900 UTC (4:00 a.m. EST) Subtropical Storm Sean forms about 445 mi (720 km) southwest of Bermuda. [86] 1800 UTC (2:00 p.m. AST) Subtropical Storm Sean transitions into a tropical storm. November 12 0300 UTC (11:00 p.m. AST November 11) Tropical Storm Sean becomes post-tropical. November 30 The 2011 Atlantic hurricane season officially ends.

Reference[1] Dorst (2009). "Subject: G1) When is hurricane season ?" (http:/ / www. aoml. noaa. gov/ hrd/ tcfaq/ G1. html). National Hurricane Center. . Retrieved September 18, 2011. [2] Daniel Brown and Todd Kimberlain (June 29, 2011). "Tropical Storm Arlene Special Advisory Number 1" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al01/ al012011. public. 001. shtml?). National Hurricane Center. . Retrieved August 14, 2011. [3] Daniel Brown and Todd Kimberlain (June 29, 2011). "Tropical Storm Arlene Special Advisory Number 1" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al01/ al012011. public. 001. shtml?). National Hurricane Center. . Retrieved August 14, 2011. [4] Eric Blake and James Franklin (June 30, 2011). "Tropical Storm Arlene Advisory Number 7" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al01/ al012011. public. 007. shtml?). National Hurricane Center. . Retrieved August 14, 2011. [5] John Cangialosi and Daniel Brown (July 1, 2011). "Tropical Depression Arlene Intermediate Advisory Number 9-A" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al01/ al012011. public_a. 009. shtml?). National Hurricane Center. . Retrieved July 22, 2011. [6] John Cangialosi and Daniel Brown (July 1, 2011). "Tropical Depression Arlene Advisory Number 10" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al01/ al012011. public. 010. shtml?). National Hurricane Center. . Retrieved July 22, 2011. [7] Richard Pasch and Stacy Stewart (July 17, 2011). "Tropical Depression Two Advisory Number 1" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al02/ al022011. public. 001. shtml?). National Hurricane Center. . Retrieved July 22, 2011. [8] Daniel Brown and Robbie Berg (July 18, 2011). "Tropical Storm Bret Intermediate Advisory 1-A" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al02/ al022011. public_a. 001. shtml?). National Hurricane Center. . Retrieved July 22, 2011. [9] Daniel P. Brown (September 16, 2011). "Tropical Storm Cindy Tropical Cyclone Report" (http:/ / www. nhc. noaa. gov/ data/ tcr/ AL032011_Cindy. pdf). National Hurricane Center. . Retrieved September 19, 2011. [10] Richard Pasch (July 22, 2011). "Tropical Depression Bret Advisory Number 18" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al02/ al022011. public. 018. shtml?). National Hurricane Center. . Retrieved July 22, 2011.

Timeline of the 2011 Atlantic hurricane season[11] Jack Beven (July 22, 2011). "Tropical Depression Bret Advisory Number 20" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al02/ al022011. public. 020. shtml?). National Hurricane Center. . Retrieved July 22, 2011. [12] Michael Brennan (October 28, 2011). "Tropical Storm Don Tropical Cyclone Report" (http:/ / www. nhc. noaa. gov/ data/ tcr/ AL042011_Don. pdf). National Hurricane Center. . Retrieved November 3, 2011. [13] Michael Brennan (August 1, 2011). "Tropical Storm Emily Special Advisory Number 1" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al05/ al052011. public. 001. shtml?). National Hurricane Center. . Retrieved August 12, 2011. [14] Lixion Avila (August 4, 2011). "Remnants of Emily Advisory Number 13" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al05/ al052011. public. 013. shtml?). National Hurricane Center. . Retrieved August 12, 2011. [15] Michael Brennan (August 6, 2011). "Tropical Depression Emily Advisory Number 14" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al05/ al052011. public. 018. shtml?). National Hurricane Center. . Retrieved August 12, 2011. [16] Michael Brennan (August 7, 2011). "Remnants Emily Advisory Number 18" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al05/ al052011. public. 018. shtml?). National Hurricane Center. . Retrieved August 12, 2011. [17] Robbie Berg (October 26, 2011). "Tropical Storm Franklin Tropical Cyclone Report" (http:/ / www. nhc. noaa. gov/ data/ tcr/ AL062011_Franklin. pdf). National Hurricane Center. . Retrieved October 27, 2011. [18] Robbie Berg (October 26, 2011). "Tropical Storm Gert Tropical Cyclone Report" (http:/ / www. nhc. noaa. gov/ data/ tcr/ AL072011_Gert. pdf). National Hurricane Center. . Retrieved October 27, 2011. [19] Eric S. Blake (November 30, 2011). "Tropical Storm Harvey Tropical Cyclone Report" (http:/ / www. nhc. noaa. gov/ data/ tcr/ AL082011_Harvey. pdf). National Hurricane Center. . Retrieved December 2, 2011. [20] Eric Blake and Michael Brennan (August 20, 2011). "Tropical Storm Irene Special Advisory Number 1" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al09/ al092011. public. 001. shtml?). National Hurricane Center. . Retrieved August 20, 2011. [21] Stacy Stewart (August 22, 2011). "Tropical Storm Irene Tropical Cyclone Update" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al09/ al092011. update. 08220530. shtml?). National Hurricane Center. . Retrieved August 22, 2011. [22] Stacy Stewart (August 22, 2011). "Hurricane Irene Advisory Number 7" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al09/ al092011. public. 007. shtml?). National Hurricane Center. . Retrieved August 22, 2011. [23] Michael Brennan (August 22, 2011). "Hurricane Irene Tropical Cyclone Update" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al09/ al092011. update. 08222348. shtml?). National Hurricane Center. . Retrieved August 23, 2011. [24] Daniel Brown (August 23, 2011). "Hurricane Irene Advisory Number 14" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al09/ al092011. public. 014. shtml?). National Hurricane Center. . Retrieved August 23, 2011. [25] Richard Pasch and Todd Kimberlain (August 24, 2011). "Hurricane Irene Intermediate Advisory Number 15A" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al09/ al092011. public_a. 015. shtml?). National Hurricane Center. . Retrieved August 24, 2011. [26] Eric Blake and Daniel Brown (August 24, 2011). "Hurricane Irene Intermediate Advisory Number 16A" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al09/ al092011. public_a. 016. shtml?). National Hurricane Center. . Retrieved August 24, 2011. [27] Todd Kimberlain (August 25, 2011). "Tropical Depression Ten Advisory Number 1" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al10/ al102011. public. 001. shtml?). National Hurricane Center. . Retrieved August 25, 2011. [28] Jack Beven (August 26, 2011). "Hurricane Irene Advisory Number 24" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al09/ al092011. public. 024. shtml?). National Hurricane Center. . Retrieved 26 August 2011. [29] Richard Pasch (August 25, 2011). "Tropical Depression Ten Advisory Number 8" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al10/ al102011. public. 008. shtml?). National Hurricane Center. . Retrieved September 1, 2011. [30] Jack Beven and Michael Brennan (August 27, 2011). "Hurricane Irene Intermediate Advisory Number 27B" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al09/ al092011. public_b. 027. shtml?). National Hurricane Center. . Retrieved September 1, 2011. [31] Daniel Brown (August 27, 2011). "Hurricane Irene Intermediate Advisory Number 28A" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al09/ al092011. public_a. 028. shtml?). National Hurricane Center. . Retrieved August 27, 2011. [32] Michael Brennan (August 28, 2011). "Hurricane Irene Tropical Cyclone Update" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al09/ al092011. update. 08280937. shtml?). National Hurricane Center. . Retrieved September 1, 2011. [33] Todd Kimberlain and Eric Blake (September 1, 2011). "Tropical Storm Jose Advisory Number 1" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al11/ al112011. public. 001. shtml?). National Hurricane Center. . Retrieved September 1, 2011. [34] Robbie Berg and Stacy Stewart (August 29, 2011). "Post-Tropical Cyclone Irene Advisory Number 35" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al09/ al092011. public. 035. shtml?). National Hurricane Center. . Retrieved September 1, 2011. [35] Michael Brennan (August 29, 2011). "Tropical Depression Twelve Advisory Number 1" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al12/ al122011. public. 001. shtml?). National Hurricane Center. . Retrieved September 1, 2011. [36] Todd Kimberlain (August 29, 2011). "Remnants of Jose Advisory Number 6" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al11/ al112011. public. 006. shtml?). National Hurricane Center. . Retrieved September 1, 2011. [37] Michael Brennan (August 30, 2011). "Tropical Storm Katia Advisory Number 5" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al12/ al122011. public. 005. shtml?). National Hurricane Center. . Retrieved September 1, 2011. [38] Eric S. Blake and Todd B. Kimberlain (December 2, 2011). "Unnamed Tropical Storm Tropical Cyclone Report" (http:/ / www. nhc. noaa. gov/ data/ tcr/ ALXX2011_Unnamed. pdf). National Hurricane Center. . Retrieved December 2, 2011. [39] Daniel Brown (September 1, 2011). "Hurricane Katia Advisory Number 12" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al12/ al122011. public. 012. shtml?). National Hurricane Center. . Retrieved September 1, 2011.

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Timeline of the 2011 Atlantic hurricane season[40] David Zelinksy and David Cangialosi (September 1, 2011). "Tropical Storm Katia Advisory Number 15" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al12/ al122011. public. 015. shtml?). National Hurricane Center. . Retrieved September 2, 2011. [41] Daniel Brown and Lixion Avila (September 2, 2011). "Tropical Depression Thirteen Advisory Number 1" (http:/ / www. nhc. noaa. gov/ archive/ 2011/ al13/ al132011. publi

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