2004 Atlantic hurricane season

Season summary map
First storm formed	July 31, 2004
Last storm dissipated	December 3, 2004
Strongest storm	Ivan – 910 mbar (hPa) (26.88 inHg), 165 mph (270 km/h)
Total depressions	16
Total storms	15
Hurricanes	9
Major hurricanes (Cat. 3+)	6
Total fatalities	3000+
Total damage	$50 billion (2004 USD)
Atlantic hurricane seasons 2002, 2003, 2004, 2005, 2006
Related article
Timeline of the 2004 Atlantic hurricane season

The 2004 Atlantic hurricane season officially began on June 1, 2004, and lasted until November 30, 2004. These dates conventionally delimit the period of each year when most tropical cyclones form in the Atlantic basin. The 2004 season exceeded these conventional limits slightly, as Tropical Storm Otto formed on the day before the last day of the season and lasted three days into December. Ironically, although a weak El Nino was emerging during the summer, the season was well above average in activity, with fifteen named storms and one of the highest Accumulated Cyclone Energy totals ever observed.

Minus a very slow start, with the first storm forming almost two months after the season began, the season was highly active. A record 8 storms formed in the month of August, which ties a few other seasons with the amount of storms that formed in month, the majority of them in September, such as September 2007, which had 8 named storms. The season was unusual, in the fact that a weak El Nino was in place throughout the season, which hinted the late start, but the season was actually above average, even though historically El Nino limits the development of storms in the Atlantic basin.

The season was also notable as one of the deadliest and most costly Atlantic hurricane seasons on record in the last decade, with at least 3,132 deaths and roughly $50 billion (2004 USD; $61.5 billion 2012 USD) in damage. The most notable storms for the season were the five named storms that made landfall in the U.S. state of Florida, three of them with at least 115 mph (185 km/h) sustained winds: Hurricanes Charley, Frances, Ivan, and Jeanne, and Tropical Storm Bonnie. This is the only time in recorded history that four hurricanes affected Florida. Jeanne wreaked havoc in Haiti, killing more than 3,000 people, and was the deadliest tropical cyclone since Mitch in 1998. Ivan raged through Grenada, Jamaica, and the Cayman Islands, while Frances and Jeanne both hit the Bahamas at full force. Charley, a small hurricane, caused significant damage in Cuba. Floodwaters in the southeastern United States from many of the hurricanes in 2004 brought to near-record levels.

Seasonal forecasts[link]

On May 17, prior to the start of the season, NOAA forecasters predicted a 50% probability of activity above the normal range, with 12–15 tropical storms, 6–8 of those becoming hurricanes, and 2–4 of those hurricanes reaching at least Category 3 strength on the Saffir-Simpson Hurricane Scale.^[2] Noted hurricane expert Dr. William Gray's May 28 prediction was similar, with 14 named storms, 8 reaching hurricane strength, and 3 reaching Category 3 strength.^[3]

On August 6, Dr. Gray announced he had revised his predictions slightly downwards, citing mild El Niño conditions, to 13 named storms, 7 hurricanes, and 3 reaching Category 3.^[4] Several days later, NOAA released an updated prediction as well, with a 90% probability of above-to-near normal activity, but the same number of storms forecast.^[5] A normal season, as defined by NOAA, has 6 to 14 tropical storms, 4 to 8 of which reach hurricane strength, and 1 to 3 of those reaching Category 3 strength.^[6] The season ended up with 16 tropical depressions, 15 named storms, 9 hurricanes, and six major hurricanes, placing it above all forecasts.

Hurricane Ivan sank and stacked numerous boats at Bayou Grande Marina at Naval Air Station Pensacola, Florida

Seasonal summary[link]

This season had 16 tropical depressions, 15 named storms, nine hurricanes, and six major hurricanes (Category 3 or higher on the Saffir-Simpson Hurricane Scale). The Accumulated Cyclone Energy figure of 225 ranks this as the fourth most active season since 1950 (behind the 2005 season, the 1950 season and the 1995 season).

August 2004 was active, with eight named storms forming during the month despite a weak El Niño emerging during the summer. In an average year, only three or four storms would be named in August.^[7] The formation of eight named storms in August breaks the old record of seven for the month, set in the 1933 and 1995 seasons. It also ties with September in the 2002, 2007 and the 2010 seasons for the most Atlantic tropical storms to form in any month.

The season's activity was reflected with a high cumulative accumulated cyclone energy (ACE) rating of 227.^[8] ACE is, broadly speaking, a measure of the power of the 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 only calculated for full advisories on tropical systems at or exceeding 34 knots (39 mph, 63 km/h) or tropical storm strength. Subtropical cyclones, such as Nicole or the early portion of Otto's track, are excluded from the total.^[9]

Hurricanes Frances (top left) and Ivan (bottom right) on September 5

The 2004 season was very deadly, with over 3,000 deaths related to the flooding rains or winds caused by the storms.^[10] Nearly all of the deaths were reported in Haiti following the floods and mudslides caused by then-Tropical Storm Jeanne.

A tropical low in May brought torrential flooding to Haiti and the Dominican Republic, killing 2,000 people and causing great damage. Though it was not officially classified as a tropical storm, it did have a circulation with loosely organized convection, resembling a subtropical cyclone.^[11]

Damage from the 2004 Atlantic hurricane season was estimated at around $50 billion (2004 USD; $61.5 billion 2012 USD), over half of which was caused by Hurricanes Charley and Ivan. These two hurricanes caused $16 billion (2004 USD; $19.7 billion 2012 USD)^[12] and $17.2 billion (2004 USD; $21.2 billion 2012 USD)^[13] in damage, respectively. While damage estimates from Hurricanes Frances and Jeanne amounted to $9.6 billion (2004 USD; $11.8 billion 2012 USD)^[14] and $7 billion (2004 USD; $8.61 billion 2012 USD)^[15], respectively. The cause of the devastating effects was due to the strength and the fact that all of the four costliest hurricanes of the 2004 season made several landfalls. Despite the season being very costly, it is a distant second to the 2005 Atlantic hurricane season, which resulted in $128 billion (2005 USD; $152 billion 2012 USD).

The 2004 season had numerous unusual occurrences. The first named storm of the season formed on August 1, giving the season the fifth-latest start since the 1952 season. Florida was hit by four hurricanes: Hurricane Charley, Frances, Ivan, and Jeanne. It was the first time four hurricanes have hit one state in one season since four hurricanes hit the Texas coast in the 1886 season, including the Indianola Hurricane of 1886 that destroyed the city of Indianola.^[17] There were many other hurricanes in the 2004 Atlantic hurricane season that were individually unusual. Hurricane Alex was the strongest hurricane on record to intensify north of 38°N latitude.^[18] One storm, Tropical Storm Earl, died out, and its remains crossed over into the Pacific Ocean, regenerated, and became Hurricane Frank in the eastern Pacific.^[19]

The most unusual storm of the season was Hurricane Ivan. Ivan first became the first major Atlantic hurricane (Category 3 or above) on record to form as low as 10°N latitude. Ivan was also recorded as the sixth most intense Atlantic hurricane on record up to that point (since pushed down to tenth), with a minimum central pressure of 910 mbar (hPa). One very unusual occurrence in relation to Ivan happened on September 22, when a remnant low from Ivan—which had traveled in a circular motion over the southeastern United States—was reclassified as a tropical depression as it moved over the Gulf of Mexico. The system was given the name Ivan and eventually strengthened into a tropical storm with winds of 65 mph (100 km/h) before making landfall along the coast of Texas, causing minimal flooding and damage.^[13]

Storms[link]

Hurricane Alex[link]

Category 3 hurricane (SSHS)
Duration	July 31 – August 6
Intensity	120 mph (195 km/h) (1-min),  957 mbar (hPa)

The first tropical depression of the season developed on July 31 off the northeast coast of Florida. On August 1, it intensified into Tropical Storm Alex, the first named storm of the season; this was the fifth-latest start to a season in 50 years.^[20] The storm moved northeastward a short distance offshore, attaining hurricane status and Category 2 status on the Saffir-Simpson Hurricane Scale. On August 3, Alex passed within 10 mi (16 km) of Cape Hatteras, North Carolina, and the western portion of its eyewall moved over land. As it moved out to sea, it initially weakened, although it re-intensified over the Gulf Stream to reach major hurricane status and peak winds of 120 mph (195 km/h); located 450 mi (710 km) south of Halifax, Nova Scotia, Alex reached major hurricane status further north than any other Atlantic hurricane but one. After passing south of Newfoundland, the hurricane quickly weakened due to cooler waters, and late on August 6 Alex was absorbed by a large extratropical cyclone.^[21]

The hurricane produced light damage in the Outer Banks, primarily from flooding and high winds. Over 100 houses were damaged, and numerous cars were disabled from the flooding.^[21] Damage totaled about $7.5 million (2004 USD, $9.23 million 2012 USD).^[22] Alex produced strong waves and rip tides along the East Coast of the United States,^[23] causing one death and several injuries.^[21][24]

Tropical Storm Bonnie[link]

Tropical storm (SSHS)
Duration	August 3 – August 13
Intensity	65 mph (100 km/h) (1-min),  1001 mbar (hPa)

While Hurricane Alex was still active, Tropical Depression Two formed east of the Lesser Antilles from a tropical wave on August 3, although it quickly lost its low-level circulation. The system continued westward, reforming into a tropical depression in the northwestern Caribbean Sea on August 8.^[25] Across the region, its effects consisted primarily of light rainfall.^[26] On August 9 the depression intensified into Tropical Storm Bonnie in the Gulf of Mexico, subsequently turning northeastward and reaching peak winds of 65 mph (100 km/h).^[25] Despite only being a tropical storm, Bonnie briefly developed a small eyewall.^[27]

Strong wind shear caused weakening, and Bonnie made landfall just south of Apalachicola, Florida as a minimal tropical storm at 1400 UTC on August 12.^[25] In the state, the storm caused flooding and minor beach erosion.^[28] While weakening across the southeastern United States, the storm produced a tornado outbreak that killed three people in North Carolina and left damage of over $1 million (2004 USD, $1.23 million 2012 USD).^[25] The cyclone degenerated into a remnant low,^[25] which subsequently entered Atlantic Canada. In New Brunswick, slick rains from the remnants of Bonnie caused an indirect fatality.^[29][29]

Hurricane Charley[link]

Category 4 hurricane (SSHS)
Duration	August 9 – August 14
Intensity	145 mph (230 km/h) (1-min),  941 mbar (hPa)

Around the same time as the previous system became Tropical Storm Bonnie, a new tropical depression developed near Grenada from a tropical wave. It quickly moved through the Caribbean Sea, encountering favorable conditions that allowed intensification into Tropical Storm and later Hurricane Charley. After passing near Jamaica, the Cayman Islands, and the Isle of Youth, the hurricane turned northward and crossed central Cuba as a Category 3 on the Saffir-Simpson Hurricane Scale. Charley briefly weakened over land before accelerating toward southwestern Florida, influenced by an unseasonably strong trough. With a small overall size, it rapidly intensified on August 13 to attain peak winds of 150 mph (240 km/h) – Category 4 status – at which strength the hurricane struck Cayo Costa. Shortly thereafter, Charley made landfall on Punta Gorda, becoming the strongest tropical cyclone to hit the United States since Hurricane Andrew. It brought strong winds across the state, and weakened significantly before emerging into the Atlantic Ocean and striking South Carolina. Charley became extratropical on August 15 near Virginia Beach, Virginia, and it later was absorbed by a cold front.^[12]

Charley caused approximately $14 billion (2004 USD, $17.2 billion 2012 USD) in damage to the United States, making it the fourth costliest hurricane in U.S. history, and the second costliest at the time. Although the storm caused serious damage, much of this was limited to a narrow swath associated with the hurricane's eye wall. Charley was a very fast-moving, compact storm, and so much of its damage was attributed to high winds rather than heavy rain. Fifteen deaths were directly attributed to Charley; four in Jamaica, one in Cuba, and ten in Florida.^[12]

Hurricane Danielle[link]

Category 2 hurricane (SSHS)
Duration	August 13 – August 21
Intensity	110 mph (175 km/h) (1-min),  964 mbar (hPa)

On August 13, a tropical wave formed into Tropical Depression Four around 275 miles (440 km) southeast of Cape Verde. It was the first of five Cape Verde-type hurricanes of 2004. Twelve hours later, Tropical Depression Four strengthened and was named Tropical Storm Danielle. Late on August 14, Danielle's wind speeds increased, and it was classified as a hurricane. Danielle moved northwest, peaking at Category 2 hurricane. It was predicted to curve towards the Azores, but curved westward on August 18 and weakened to a tropical storm. By August 19, the storm had become stationary with minimal storm strength 810 miles (1305 km) southwest of the Azores. The storm was downgraded to a tropical depression the next day, and degenerated to a broad low-pressure area on August 21. The remnants of Danielle moved to the west and ultimately to the northwest.^[30]

Tropical Storm Earl[link]

Tropical storm (SSHS)
Duration	August 13 – August 15
Intensity	50 mph (85 km/h) (1-min),  1009 mbar (hPa)

Earl formed initially as the fifth tropical depression of the season on August 13 east of the Lesser Antilles. After traveling west, it reached tropical storm strength on August 14 around 375 miles (605 km) southeast of Barbados. On August 15, Earl passed just south of Grenada and entered the Caribbean. The storm had degenerated by that point, and that night would have been classified as a tropical wave. However, the government of Venezuela denied access to their airspace for storm reconnaissance aircraft. An on-site assessment of Earl's circulation was needed, since satellite observations are inaccurate for that purpose. Earl also posed a threat to land, so advisories continued for another 12 hours.^[19]

The next morning a reconnaissance aircraft was able to reach the storm. It found no closed circulation, and Earl was reclassified as a tropical wave on August 16. Remnants of the storm continued across the Caribbean and into Central America, later becoming Tropical Depression Eight-E and then Hurricane Frank in the Pacific Ocean. Earl caused minor damage to Grenada and St. Vincent and the Grenadines.

Hurricane Frances[link]

Category 4 hurricane (SSHS)
Duration	August 25 – September 8
Intensity	145 mph (230 km/h) (1-min),  935 mbar (hPa)

Frances began as Tropical Depression Six on August 24, and it became a named storm on August 25 while well east of the Windward Islands. Frances strengthened rapidly, reaching Category 4 intensity by August 27. Initially forecast to turn north and potentially threaten Bermuda, conditions changed and Frances's predicted track shifted westward. After grazing the Turks and Caicos Islands, it plowed through the Bahamas. From September 2 through September 4, Frances slowly ground its way across the Bahamas. Its slow movement allowed a record 2.5 to 3 million Floridians to evacuate their homes. However, as it ground its way across the Bahamas, it weakened to a Category 2 hurricane due to wind shear, although it was still a very large storm.^[14]

After sitting stationary off the coast of Florida for nearly 24 hours, Frances finally moved onto the coast of Florida in the early hours of September 5. It traveled northwest over land, briefly emerging over the Gulf of Mexico and striking the Florida Panhandle. As it passed over Georgia on September 6, it caused heavy rainfall across the southern United States. Over 15 inches (380 mm) of rain were recorded in some places in North Carolina and Virginia, causing heavy flooding. Frances was downgraded to a tropical depression and dissipated over Pennsylvania on September 9.^[14]

Damage to the United States was approximately $9 billion (2004 USD, $11.1 billion 2012 USD), making it the tenth costliest hurricane in U.S. history. Most of Hurricane Frances's damage occurred in Florida as a result of the storm's slow movement, large size, and long duration of winds. The storm is directly responsible for seven deaths; one in the Bahamas and six in the United States. Hurricane Frances also produced 103 tornadoes as it moved its way through the United States.^[14]

Hurricane Gaston[link]

Category 1 hurricane (SSHS)
Duration	August 27 – September 1
Intensity	75 mph (120 km/h) (1-min),  986 mbar (hPa)

Tropical Depression Seven formed at 5 p.m. EDT (2100 UTC) on August 27, around 140 miles (225 km) southeast of Charleston, South Carolina. The depression meandered off the coast for the rest of the day, strengthening into Tropical Storm Gaston by midday August 28. At 10 a.m. EDT (1400 UTC) on August 29, Gaston made landfall on the coast of Bulls Bay, South Carolina, near the towns of McClellanville and Awendaw. It was downgraded to a tropical depression later that day. The storm made landfall in almost the same location as Hurricane Hugo in 1989.^[31]

At landfall the storm was originally classified as just shy of hurricane strength. While wind damage in South Carolina was minimal, the slow-moving storm produced five to ten inches (125 to 250 mm) of rain along its path, causing extensive flooding. Gaston moved north over land, weakening to a tropical depression but still bringing torrential rain to central Virginia, where at least eight people were killed in the ensuing floods. The Shockoe Bottom entertainment district near downtown Richmond was devastated by the flooding. Total damage was estimated at about $130 million.

Late on August 30, as Tropical Depression Gaston crossed Chesapeake Bay, its winds strengthened, and it was again classified as a tropical storm. It headed out over the Atlantic and became extratropical on September 1, about 185 miles (300 km) southeast of Halifax, Nova Scotia.

On November 19, after a detailed analysis by the NHC, surface-level winds were determined to be about 75 mph (120 km/h) at landfall, and Gaston was reclassified as a Category 1 hurricane.

Tropical Storm Hermine[link]

Tropical storm (SSHS)
Duration	August 27 – August 31
Intensity	60 mph (95 km/h) (1-min),  1002 mbar (hPa)

Hermine formed out of an organized area of disturbed weather that had formed about 325 miles (520 km) southeast of Cape Hatteras, North Carolina, or 360 miles (580 km) west of Bermuda, and moved rapidly north towards Cape Cod. On its northward trek, Hermine left behind most of its convection. The storm made landfall near New Bedford, Massachusetts, early on August 31, appearing as little more than a low-level swirl of clouds. It became extratropical a few hours later. The remnant low centre tracked up the Bay of Fundy later on August 31. Some rainfall and thunderstorms over Long Island and parts of New England were attributed to Hermine, but most people did not realize a tropical storm had struck.^[32]

There were no casualties or reports of major damage caused by Hermine. Locally heavy rain did fall in portions of southern New Brunswick, which received 1.6 to 2.2 inches (41 to 56 mm). Minor basement flooding and street closures were also reported in Moncton, New Brunswick.^[33]

Hurricane Ivan[link]

Category 5 hurricane (SSHS)
Duration	September 2 – September 24
Intensity	165 mph (270 km/h) (1-min),  910 mbar (hPa)

Ivan was a Cape Verde-type hurricane that began as Tropical Depression Nine on September 2. It became a tropical storm on September 3, and a hurricane on September 5 while 1,040 miles (1670 km) east of the Windward Islands, at 9.9° N. Later that day, while at 10.6° N, Ivan unexpectedly began to rapidly strengthening, and reached Category 4 intensity by that evening. It was the strongest storm to have ever been known to intensify that far south. Ivan weakened slightly while continuing westward, and struck Grenada on September 7.^[13]

While moving westward through the Caribbean Sea, Ivan quickly intensified to a Category 5 hurricane. It fluctuated in strength over the next few days, and passed within 30 miles (50 km) of Grand Cayman on September 11. Ivan grazed western Cuba as a Category 5, and moved into the Gulf of Mexico. The hurricane turned northward over cooler waters, and made landfall in southern Alabama on September 16 as a 120 mph (195 km/h) hurricane. Ivan weakened rapidly to a tropical depression over Alabama, accelerated to the northeast, and became extratropical over the Delmarva Peninsula on September 18. Ivan's remnants turned to the southeast then southwest, and gradually re-organized over the warm Gulf Stream waters. After crossing southern Florida on September 21 the system regained tropical characteristics over the Gulf of Mexico, and became a tropical storm on September 23 while 140 miles (220 km) south of Louisiana. Ivan moved to the northwest, and reached winds of 60 mph (95 km/h) before making landfall near Cameron, Louisiana. Ivan quickly deteriorated over Texas, and dissipated on September 24.

Hurricane Ivan directly killed 92 people throughout the Caribbean and United States and caused approximately $13 billion in damage to the United States, making it the fifth costliest hurricane in United States history. The hurricane destroyed 90% of Grenada's structures and devastated the island's economy, and destroyed 85% of the buildings on Grand Cayman. The combination of Hurricane Ivan with the previous rains of Frances brought many rivers in the Southeastern U.S. to near-record flood levels. Ivan was the strongest storm of the season, and the only 2004 Atlantic hurricane to reach Category 5 intensity. Its low pressure reading of 910 mbar (27 inHg) made it the sixth most intense Atlantic hurricane on record at the time.

Tropical Depression Ten[link]

Tropical depression (SSHS)
Duration	September 7 – September 9
Intensity	35 mph (55 km/h) (1-min),  1009 mbar (hPa)

A tropical wave exited Africa on August 29. It passed north of Cape Verde on August 30, and over the next week moved to the northwest, north, and eventually to the northeast. On September 7 a low-level circulation formed, and the system became a tropical depression; at the time, convection was displaced to the northeast of the center due to upper-level wind shear. Advisories were not issued until two days later. The depression failed to intensify significantly, only reaching a peak of 35 mph (56 km/h) and a minimum pressure was 1009 mbar.^[34] Some tropical cyclone advisories stated that there was a small possibility for Tropical Depression Ten to become a tropical storm, though it was not forecast to do so.^[35] On September 9, wind shear displaced the deep convection from the center,^[36] and the NHC issued the final advisory on September 10 after the depression became devoid of almost any convection. At the time, it was located about 380 mi (610 km) west-southwest of the Azores.^[37] The remnant low headed generally south-southeastward, remaining to the south of the Azores before dissipating on September 10. There were no reports of damage or casualties.^[34]

Hurricane Jeanne[link]

Category 3 hurricane (SSHS)
Duration	September 13 – September 28
Intensity	120 mph (195 km/h) (1-min),  950 mbar (hPa)

Jeanne formed as a tropical depression east-southeast of Guadeloupe on the evening of September 13. Having strengthened to a tropical storm, Jeanne crossed Puerto Rico on September 15. It then moved toward Hispaniola, barely reaching hurricane strength before making landfall on September 16. It tracked slowly across the northern coast of the Dominican Republic and Haiti, its heavy rains bringing mudslides and flooding. Jeanne's unusually slow journey was actually caused by a weakening Hurricane Ivan. Ivan broke up a trough that was fuelling Jeanne's steering currents. Interaction with Hispaniola caused it to degenerate into a tropical depression.^[15]

After wreaking havoc on Hispaniola, Jeanne struggled to reorganize. However, it eventually began strengthening and headed north. After performing a complete loop over the open Atlantic, it headed westwards, strengthening into a Category 3 hurricane and passing over the islands of Great Abaco and Grand Bahama in the Bahamas on September 25. Jeanne made landfall later in the day near Stuart, Florida just 2 miles (3 kilometers) from where Frances had struck 3 weeks earlier. Building on the rainfall of Frances and Ivan, Jeanne brought near-record flood levels as far north as West Virginia and New Jersey before its remnants turned east into the open Atlantic.

Jeanne is blamed for at least 3,006 deaths in Haiti with about 2,800 in Gonaïves alone, which was nearly washed away by floods and mudslides. The storm also caused 7 deaths in Puerto Rico, 18 in the Dominican Republic and at least 4 in Florida, bringing the total number of deaths to at least 3,025. Final property damage in the United States was $6.8 billion, making this the 13th costliest hurricane in U.S. history.

Hurricane Karl[link]

Category 4 hurricane (SSHS)
Duration	September 16 – September 24
Intensity	145 mph (230 km/h) (1-min),  938 mbar (hPa)

Tropical Depression Twelve formed from a tropical wave about 670 miles (1,080 km) west-southwest of the Cape Verde islands on September 16. It became Tropical Storm Karl at 11 p.m. AST (0300 UTC) that day. Early on September 18, it strengthened rapidly to become a hurricane and was a major hurricane later that day.^[38]

Karl continued strengthening and became a 145 mph (230 km/h) Category 4 hurricane on September 21. It fluctuated in intensity over the next few days, reaching Category 4 strength on two different occasions. It moved steadily northwards, staying hundreds of miles from any land, until it began to weaken and become extratropical over cooler waters. Karl was still of Category 1 strength when it became an extratropical system on September 24 over the northern Atlantic at about 47° N. The extratropical system struck the Faroe Islands two days later with 144 km/h (89 mph) wind gusts.^[39]

Hurricane Lisa[link]

Category 1 hurricane (SSHS)
Duration	September 19 – October 3
Intensity	75 mph (120 km/h) (1-min),  987 mbar (hPa)

Tropical Depression Thirteen developed from a tropical wave 650 miles (1,045 km) west-southwest of the Cape Verde islands on September 19. It became Tropical Storm Lisa at 8 a.m. AST on September 20 with maximum sustained winds of 50 mph (80 km/h). A very small storm, its development was hindered by its proximity to Hurricane Karl. On September 22, Lisa began merging with a large tropical disturbance to its east and weakened to a tropical depression for a couple of days before regaining tropical storm strength on September 25. By then it was heading generally northwards in the mid-Atlantic. Lisa went through several phases of weakening and strengthening as it headed north, finally reaching hurricane strength on October 1, and again the next day.^[40]

Lisa was a hurricane only briefly, moving over cooler waters and weakening to a tropical storm. It became extratropical early on October 3 while located about 475 miles (760 km) north-northwest of the Azores. It never threatened any land area. Lisa's total development time from tropical depression to hurricane, at 12½ days, is the second longest period for an Atlantic tropical cyclone to reach hurricane strength, only to Hurricane Josephine of 1990.^[40]

Tropical Storm Matthew[link]

Tropical storm (SSHS)
Duration	October 8 – October 10
Intensity	45 mph (75 km/h) (1-min),  997 mbar (hPa)

Matthew began with a tropical wave that entered the southwestern Gulf of Mexico. This wave grew into a large area of low pressure in the western Gulf. The nontropical low began feeding moisture into a cold front that was traversing the United States, causing heavy rainfall across Louisiana, East Texas, and Arkansas.^[41]

On the afternoon of October 8, the low pressure system developed into Tropical Storm Matthew 260 miles (420 km) east-southeast of Brownsville, Texas. Matthew was a minimal tropical storm, and its sustained winds stayed at or near 40 mph (64 km/h) from its naming until landfall on October 10. It became extratropical inland over Louisiana later in the day, and dissipated when it was near El Dorado, Arkansas.

Matthew brought up to 12 inches (300 mm) of rain to southern Louisiana. About a dozen homes were flooded in Terrebonne Parish after a canal levee burst, and streets in St. Bernard Parish were reportedly under 2 feet (60 cm) of water. The remnants of Matthew continued to spin inland and delivered heavy rainfall for at least five more days. No injuries or deaths were reported.

Subtropical Storm Nicole[link]

Subtropical storm (SSHS)
Duration	October 10 – October 11
Intensity	50 mph (85 km/h) (1-min),  986 mbar (hPa)

The interaction between an upper-level trough and a cold front developed a low pressure area on October 8 to the southwest of Bermuda. It developed a curved band of convection northwest of the center, and it organized into Subtropical Storm Nicole by October 10. An approaching mid-level trough turned the system northeastward, and early on October 11 it passed about 60 miles (95 km) northwest of Bermuda.^[42] As it passed the island, Nicole and its precursor dropped 5.86 inches (148 mm) of rainfall,^[43] and wind gusts reached 60 mph (97 km/h).^[42] The winds left 1,800 homes and businesses without power, while the unsettled conditions caused airport delays.^[44]

After passing Bermuda, Nicole developed an area of convection near the center,^[42] suggesting the beginning of a transition to a tropical cyclone.^[45] However, strong wind shear caused weakening after the storm reached peak winds of 50 mph (85 km/h). A larger extratropical storm absorbed Nicole on October 11 to the south of Nova Scotia.^[42] The combination of the two storms produced flooding rains and gusty winds across Atlantic Canada.^[46] Since 2002, subtropical storms have been assigned names from the same sequence as tropical storms. Nicole was the first named storm under this policy that never achieved tropical status.^[16]

Tropical Storm Otto[link]

Tropical storm (SSHS)
Duration	November 29 – December 3
Intensity	50 mph (85 km/h) (1-min),  995 mbar (hPa)

After a period of inactivity lasting seven weeks, Subtropical Storm Otto formed on November 29 about 1,150 mi (1850 km) southeast of Bermuda. It originated from an extratropical low, which itself developed from a cold front that left the United States coast on November 21. The subtropical storm moved northwestward at first through a weakness in the subtropical ridge, reaching peak winds of 50 mph (85 km/h) before turning to the north. Convection gradually increased, and Otto transitioned into a tropical storm late on November 30, which is the last day of the hurricane season. Continuing into December, Otto began slowly weakening as it turned southward, due to a building ridge moving the storm over cooler water temperatures. On December 2, the storm weakened to a tropical depression, and it degenerated into a remnant low the following day. The remnants lasted until December 5 before dissipating about 920 mi (1480 km) northeast of the northern Leeward Islands, without ever having affected land.^[47]

Season effects[link]

This is a table of the storms in 2004 and the affected regions, if any. Deaths in parentheses are additional and indirect (an example of an indirect death would be a traffic accident), but are still storm-related. Damage and deaths include totals while the storm was extratropical or a wave or low. In addition, the location of landfall, if any, will be in bold.

Storm names[link]

The following names were used for named storms that formed in the Atlantic basin in 2004. The names not retired from this list will be used again in the 2010 season. This is the same list used for the 1998 season except for Gaston and Matthew, which replaced Georges and Mitch. Storms were named Gaston, Matthew, and Otto for the first time in 2004. Names that were not assigned are marked in gray.

Retirement[link]

The World Meteorological Organization retired four names in the spring of 2005: Charley, Frances, Ivan, and Jeanne. They were replaced in 2010 by Colin, Fiona, Igor, and Julia. The 2004 season was tied with the 1955 season and 1995 season for the most storm names retired after a single season until the 2005 season, when five names were retired.

See also[link]

Tropical cyclones portal

	Book: 2004 Atlantic hurricane season
Wikipedia books are collections of articles that can be downloaded or ordered in print.

• 2004 Pacific hurricane season
• 2004 Pacific typhoon season
• 2004 North Indian Ocean cyclone season
• South-West Indian Ocean cyclone seasons: 2003–04, 2004–05
• Australian region cyclone seasons: 2003–04, 2004–05
• South Pacific cyclone seasons: 2003–04, 2004–05

References[link]

External links[link]

• Satellite movie of 2004 Atlantic hurricane season
• 2004 NHC Tropical Cyclone Advisory Archive
• U.S. Rainfall from Tropical Cyclones in 2004
• NOAA hurricane season outlook
• William Gray's 2004 preseason forecast
• Tropical cyclone images and movies – Northern hemisphere 2004, from the United Kingdom Met Office
• Effects of the Third-Quarter Hurricanes on Income Measures

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Tropical cyclones of the 2004 Atlantic hurricane season
A B C D E F G H I 10 J K L M N O		Saffir–Simpson Hurricane Scale TD TS C1 C2 C3 C4 C5

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Tracks of all known Atlantic tropical cyclones from 1851 to 2005

The Atlantic hurricane season is the period in a year when hurricanes usually form in the Atlantic Ocean. Tropical cyclones in the North Atlantic are called hurricanes, tropical storms, or tropical depressions. In addition, there have been several storms over the years that have not been fully tropical which are categorised as subtropical depressions and subtropical storms.

Worldwide, tropical cyclone activity peaks in late summer, when the difference between temperatures aloft and sea surface temperatures is the greatest. However, each particular basin has its own seasonal patterns. On a worldwide scale, May is the least active month, while September is the most active. We also notice that many of the Atlantic hurricanes occur in the famous Bermuda Triangle. ^[1] In the Northern Atlantic Ocean, a distinct hurricane season occurs from June 1 to November 30, sharply peaking from late August through September;^[1] the season's climatological peak of activity occurs around September 10 each season.^[2]

Tropical disturbances that reach tropical storm intensity are named from a pre-determined list. On average, 10.1 named storms occur each season, with an average of 5.9 becoming hurricanes and 2.5 becoming major hurricanes (Category 3 or greater). The most active season was 2005, during which 28 tropical cyclones formed, of which a record 15 became hurricanes. The least active season was the 1914, with only one known tropical cyclone developing during that year.^[3] The Atlantic hurricane season is a time when most tropical cyclones are expected to develop across the northern Atlantic Ocean. It is currently defined as the time frame from June 1 through November 30, though in the past the season was defined as a shorter time frame. During the season, regular tropical weather outlooks are issued by the National Hurricane Center, and coordination between the Hydrometeorological Prediction Center and National Hurricane Center occurs for systems which have not formed yet, but could develop during the next three to seven days.

Concept[link]

The basic concept of a hurricane season began during 1935,^[4] when dedicated wire circuits known as hurricane circuits began to be set up along the Gulf and Atlantic coasts,^[5] a process completed by 1955.^[6] It was originally the time frame when the tropics were monitored routinely for tropical cyclone activity, and was originally defined as from June 15 through October 31.^[7] Over the years, the beginning date was shifted back to June 1, while the end date was shifted to November 15,^[5] before settling at November 30 by 1965.^[8][9] This was when hurricane reconnaissance planes were sent out to fly across the Atlantic and Gulf of Mexico on a routine basis to look for potential tropical cyclones, in the years prior to the continuous weather satellite era.^[7] After regular satellite surveillance began, hurricane hunter aircraft flew only into areas which were spotted first by satellite imagery.^[10]

Operations[link]

During the hurricane season, the National Hurricane Center routinely issues their Tropical Weather Outlook product, which identifies areas of concern within the tropics which could develop into tropical cyclones. If systems occur outside the defined hurricane season, special Tropical Weather Outlooks will be issued.^[11] Routine coordination occurs at 1700 UTC each day between the Hydrometeorological Prediction Center and National Hurricane Center to identify systems for the pressure maps three to seven days into the future within the tropics, and points for existing tropical cyclones six to seven days into the future.^[12] Possible tropical cyclones are depicted with a closed isobar, while systems with less certainty to develop are depicted as "spot lows" with no isobar surrounding them.

HURDAT[link]

The North Atlantic hurricane database, or HURDAT, is the database for all tropical storms and hurricanes for the Atlantic Ocean, Gulf of Mexico and Caribbean Sea, including those that have made landfall in the United States. The original database of six-hourly positions and intensities were put together in the 1960s in support of the Apollo space program to help provide statistical track forecast guidance. In the intervening years, this database — which is now freely and easily accessible on the Internet from the National Hurricane Center's (NHC's) Webpage — has been utilized for a wide variety of uses: climatic change studies, seasonal forecasting, risk assessment for county emergency managers, analysis of potential losses for insurance and business interests, intensity forecasting techniques and verification of official and various model predictions of track and intensity.

HURDAT was not designed with all of these uses in mind when it was first put together and not all of them may be appropriate given its original motivation. HURDAT contains numerous systematic as well as some random errors in the database. Additionally, analysis techniques have changed over the years at NHC as their understanding of tropical cyclones has developed, leading to biases in the historical database. Another difficulty in applying the hurricane database to studies concerned with landfalling events is the lack exact location, time and intensity at hurricane landfall.

Re-analysis Project[link]

HURDAT is regularly updated annually to reflect the previous season's activity. The older portion of the database has been regularly revised since 2001. The first time in 2001 led to the addition of tropical cyclone tracks for the years 1851 to 1885. The second time was August 2002 when Hurricane Andrew was upgraded to a Category 5. Recent efforts into uncovering undocumented historical hurricanes in the late 19th and 20th centuries by various researchers have greatly increased our knowledge of these past events. Possible changes for the years 1930-2011 are not yet incorporated into the HURDAT database. Because of all of these issues, a re-analysis of the Atlantic hurricane database is being attempted that will be completed in three years.

In addition to the groundbreaking work by Partagas, additional analyses, digitization and quality control of the data was carried out by researchers at the NOAA Hurricane Research Division funded by the NOAA Office of Global Programs. This re-analysis will continue to progress through the remainder of the 20th Century.^[13]

The National Hurricane Center's Best Track Change Committee had approved changes for the 1851-1930 hurricane seasons, as well as a few recent cyclones, such as Hurricane Andrew. Official changes to the Atlantic hurricane database are approved by the National Hurricane Center Best Track Change Committee. Thus research conducted by Chris Landsea and colleagues as part of the Atlantic hurricane database reanalysis project are submitted through this review process. Not all Landsea's recommendations are accepted by the Committee.

Pre-1870[link]

1800s[link]

1870s[link]

1880s[link]

1890s[link]

1900s[link]

1900-1909[link]

1910s[link]

1920s[link]

1930s[link]