2007 Atlantic hurricane season
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 Season summary map |
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| First storm formed: | May 9, 2007 |
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| Last storm dissipated: | December 13, 2007 |
| Strongest storm: | Dean - 905 mbar (hPa) (26.74 inHg), 175 mph (280 km/h) |
| Total depressions: | 17 |
| Total storms: | 15 |
| Hurricanes: | 6 |
| Major hurricanes (Cat. 3+): | 2 |
| Total fatalities: | ≥416 |
| Total damage: | ~ $7.5 billion (2007 USD) |
| Atlantic hurricane seasons 2005, 2006, 2007, 2008, 2009 |
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The 2007 Atlantic hurricane season was an event in the annual cycle of tropical cyclone formation. It officially started June 1, 2007, and ended November 30, 2007, dates that conventionally delimit the period when most tropical cyclones form in the Atlantic basin during the year. However, the formation of Subtropical Storm Andrea on May 9, 2007 marked an earlier beginning to the season, and the season extended past the official end of the season when Tropical Storm Olga developed on December 11. The 2007 season was fairly active, with 15 named storms, though the intensities of the storms did not meet the predictions.
On August 18, Hurricane Dean was upgraded to category 5 status and eventually made landfall at that strength on the Mexican Yucatán Peninsula. When Hurricane Felix reached category 5 status, 2007 became one of four recorded Atlantic seasons that have had more than one category 5 storm — the others being 1960, 1961 and 2005 — and the only time two Atlantic hurricanes have ever made landfall at Category 5 strength in the same season. Dean and Felix also both reached Category 5 strength more than once, the first such occurrence in an Atlantic hurricane season. Also, the 2007 season was the second season on record that an Atlantic hurricane and an eastern Pacific hurricane made landfall on the same day (Felix and Henriette). Hurricane Humberto also became the fastest developing storm on record to be so close to land; it strengthened from a 35 mph (55 km/h) tropical depression to a 90 mph (150 km/h) hurricane in 14 hours while 15 miles (24 km) off the coast of Texas. September had a record tying 8 storms, but the strengths and durations of most of the storms were low. Hurricane Noel was the deadliest storm of the season, killing 169 people. The post season Tropical Storm Olga caused 40 deaths in the northern Caribbean, primarily in the Dominican Republic.
[edit] Seasonal forecasts
Forecasts of hurricane activity are issued before each hurricane season by noted hurricane experts Philip J. Klotzbach, Dr. William M. Gray, and their associates at Colorado State University; and separately by NOAA forecasters.
Klotzbach's team (formerly led by Dr. Gray) defined the average number of storms per season (1950 to 2000) as 9.6 tropical storms, 5.9 hurricanes, and 2.3 major hurricanes (storms exceeding Category 3 strength in the Saffir-Simpson Hurricane Scale). A normal season, as defined by NOAA, has 9 to 12 named storms, with 5 to 7 of those reaching hurricane strength, and 1 to 3 major hurricanes.[1][2]
| Source | Date | Named storms |
Hurricanes | Major hurricanes |
| CSU | Average (1950–2000)[1] | 9.6 | 5.9 | 2.3 |
| NOAA | Average (1950–2005)[2] | 11.0 | 6.2 | 2.7 |
| Record high activity | 28 | 15 | 8 | |
| Record low activity | 4 | 2 | 0 | |
| –––––––––––––––––––––––––––––––––––––––––– | ||||
| CSU | December 8, 2006 | 14 | 7 | 3 |
| CSU | April 3, 2007 | 17 | 9 | 5 |
| NOAA | May 22, 2007 | 13–17 | 7–10 | 3–5 |
| CSU | May 31, 2007 | 17 | 9 | 5 |
| UKMO | June 19, 2007 | 9–15 | N/A | N/A |
| CSU | August 3, 2007 | 15 | 8 | 4 |
| NOAA | August 9, 2007 | 13–16 | 7–9 | 3–5 |
| CSU | September 4, 2007 | 15 | 7 | 4 |
| CSU | October 2, 2007 | 17 | 7 | 3 |
| –––––––––––––––––––––––––––––––––––––––––– | ||||
| Actual activity | 15 | 6 | 2 | |
[edit] Pre-season forecasts
On December 8, 2006, Klotzbach's team issued its first extended-range forecast for the 2007 season, predicting above-average activity (14 named storms, 7 hurricanes, 3 of Category 3 or higher).[1]
The team predicted a high potential for at least one major hurricane to directly impact the United States: the forecast indicated a 64% chance of at least one major hurricane striking the U.S. mainland, which included a 40% chance of at least one major hurricane strike on the East Coast of the United States including the Florida peninsula, and a 40% chance of at least one major hurricane strike on the Gulf Coast of the United States from the Florida Panhandle westward. The potential for major hurricane activity in the Caribbean was forecast to be above average, and the team predicted El Niño to dissipate by the active portion of the season.[1]
On April 3 a new forecast was issued, calling for a very active hurricane season of 17 named storms, 9 hurricanes and 5 intense hurricanes.[3]
The increase in the forecast was attributed to the rapid dissipation of El Niño conditions. The team also forecast a neutral or weak-to-moderate La Niña for the hurricane season, and noted that sea surface temperatures were much higher than long-term averages.[4] The potential for at least one major hurricane impacting the U.S. was increased to 74%, with the U.S. East Coast potential increased to 50% and from the Florida Panhandle westward to Brownsville, Texas increased to 49%.[4] However, Klotzbach noted that while they were calling for an active season, it was not forecast to be "as active as the 2004 and 2005 seasons".[3]
On May 22, 2007, NOAA released their pre-season forecast for the 2007 season. They predicted 13 to 17 named storms, with 7 to 10 becoming hurricanes, and 3 to 5 becoming major hurricanes.[5]
One day before the official start of the season, the CSU team issued their final set of pre-season forecasts, making no change to the numbers from their April forecast.[6]
On June 19, 2007, The United Kingdom Met Office released[7] predictions for the remainder of the season based on a new prediction model. The Met Office predicted 10 named storms, not including Andrea and Barry, with a 70% chance of 7–13 named storms. The forecast did not include specific predictions for the number of hurricanes or major hurricanes.[7]
[edit] Midseason outlooks
On August 3, 2007, Klotzbach's team lowered their season estimate to 15 named storms, with eight becoming hurricanes and four becoming major hurricanes. They noted that conditions had become slightly less favorable for storms than they were earlier in the year. Sea surface temperature anomalies were cooler, and there were several incidences of Saharan Air Layer outbreaks. ENSO conditions were also noted to have been slightly cooler.[8]
On August 9, 2007, the NOAA revised their season estimate slightly downwards to 13–16 named storms, with 7–9 becoming hurricanes and 3–5 becoming major hurricanes. However, they reaffirmed their call for an above-average season. They attributed the increase in confidence of an above-average season to warmer-than-normal sea surface temperatures in parts of the Atlantic Ocean and Caribbean Sea, as well as an updated forecast that La Niña conditions were likely during the peak of the season.[9]
On September 4, 2007, Klotzbach's team lowered their season estimate to 15 named storms, with 7 becoming hurricanes and 4 becoming major hurricanes.[10]
On October 2, 2007, Klotzbach's team adapted their season estimate to 17 named storms, with 7 becoming hurricanes and 3 becoming major hurricanes. The estimate of 7 hurricanes assumed that Karen was a hurricane[11]
[edit] Storms
[edit] Subtropical Storm Andrea
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| Duration | May 9 – May 11 | |||
| Intensity | 60 mph (95 km/h), 1001 mbar (hPa) | |||
- Main article: Subtropical Storm Andrea (2007)
A large extratropical cyclone that formed off the mid-Atlantic coast on May 6 deepened steadily along a cold front that pushed through Florida. When the system lost most of its baroclinic support, development ceased until its low moved into warmer waters near the Bahamas. However, interaction between the low and a strong high-pressure system to the north generated hurricane-force winds in the system. Decreasing vertical wind shear allowed the storm to generate deeper convection much closer to the center.[12] By May 9 the previously extratropical cyclone had transformed into Subtropical Storm Andrea while located about 140 miles (225 km) southeast of Savannah, Georgia.[13]
Tropical storm watches were immediately issued for parts of coastal Georgia and Florida, though all were later dropped.[12] Andrea was the first named storm to form in May since Arlene in 1981, and the first pre-season storm since Ana in April 2003.[14] Andrea began its subtropical phase as it was weakening, and continued this deterioration as it moved southward into an environment with higher wind shear. By May 11 Andrea had lost all significant convection and degenerated into a remnant low. Though it produced intermittent bursts of convection, Andrea's chance of regeneration was extinguished when an advancing cold front pushed it northward and eventually absorbed the system.[12]
The storm produced rough surf and large waves along the coastline from Florida to North Carolina, causing beach erosion and some damage.[15] No deaths were directly attributable to Andrea, though six people died from the waves generated during its extratropical phase. The storm was also blamed for high winds that could have fueled severe wildfires in northern Florida and southern Georgia.[16] However, because Andrea never made landfall, most of the resulting damage was associated with large waves, higher than normal tides, associated coastal flooding, and beach erosion caused by the storm.[12]
- See the NHC's advisory archive on Subtropical Storm Andrea.
- See NHC's end-of-season report on Subtropical Storm Andrea.
[edit] Tropical Storm Barry
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| Duration | June 1 – June 2 | |||
| Intensity | 60 mph (95 km/h), 997 mbar | |||
- Main article: Tropical Storm Barry (2007)
On May 30, a broad low pressure area formed in the Gulf of Honduras. Moving northward, the system slowly deepened as it moved through the northwest Caribbean Sea and into the southeast Gulf of Mexico. On June 1, the first day of the officially defined hurricane season, this cyclone organized into Tropical Storm Barry despite being located in an area of high shear, and warnings were immediately issued along the western Florida coastline. Barry provided much-needed precipitation to parts of Florida and Georgia, which were experiencing drought conditions.[17] Barry made landfall near Tampa Bay, Florida on June 2 as a minimal tropical storm. Soon thereafter Barry was downgraded to a tropical depression as it began its extratropical transition. Barry became an extratropical cyclone late in the afternoon of June 2. On June 3, the cyclone moved up the coast of the Carolinas bringing rains into the Mid-Atlantic states and New England. By June 5 its center had moved northward into Atlantic Canada.
- See the NHC's advisory archive on Tropical Storm Barry.
- See the HPC's advisory archive on Tropical Storm Barry.
- See NHC's end-of-season report on Tropical Storm Barry.
[edit] Tropical Storm Chantal
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| Duration | July 31 – August 1 | |||
| Intensity | 50 mph (85 km/h), 994 mbar | |||
- Main article: Tropical Storm Chantal (2007)
An area of low pressure developed near the Bahamas on July 28, and slowly organized while moving to the north-northeast. Late on July 30, it was upgraded to a tropical depression, the third of the season, after maintaining deep convection near the center for most of the day.
On July 31, the system strengthened into a tropical storm south of Nova Scotia, the first in nearly two months. However, Chantal became extratropical later that day as it tracked towards Newfoundland over the cooler waters of the north Atlantic.
On August 1, flooding was reported from Placentia to the capital city of St. John's, where about 100 mm (4 inches) of rain caused the postponement of the annual Royal St. John's Regatta. Up to 150 mm (6 inches) of rain fell in the Whitbourne area, according to Environment Canada. [18] The most serious flooding was across the southern Avalon Peninsula, where dozens of roads were washed out, houses were flooded above their basements and several communities were isolated.[19] Ferry service between Argentia and North Sydney, Nova Scotia, was suspended, and one ferry was diverted to Port aux Basques.[20]
States of emergency were declared in at least five communities in the areas surrounding Placentia Bay and Conception Bay, and the Newfoundland and Labrador Municipal Affairs Minister Jack Byrne requested a federal disaster area declaration. Damage is estimated to be well into the millions of dollars, with at least $4 million in damage in the town of Placentia alone.[21]
- See the NHC's advisory archive on Tropical Storm Chantal.
- See NHC's end-of-season report on Tropical Storm Chantal.
[edit] Hurricane Dean
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| Duration | August 13 – August 23 | |||
| Intensity | 175 mph (280 km/h), 905 mbar | |||
- Main article: Hurricane Dean (2007)
A vigorous tropical wave moved off the west coast of Africa in the second week of August. It quickly organized itself and formed into a low on August 12. Tropical Depression Four formed on August 13 in the eastern Atlantic from a tropical wave to the south of Cape Verde. The depression was already exhibiting persistent deep convection, albeit confined to the western portion of its circulation due to easterly wind shear.[22] The depression was expected to strengthen significantly over the following days[22] due to abating wind shear and warming sea surface temperatures which created conditions favorable for tropical intensification.[23] The depression moved briskly westward, south of a deep layered ridge,[24] quickly escaping the easterly shear.[25]
Based on satellite images and microwave and QuikSCAT data, the depression was upgraded to Tropical Storm Dean on August 14.[26] The storm continued to strengthen overnight as it gained organization,[27] and on August 16 it was upgraded to the first hurricane of the 2007 season.[28]
On August 17 the eye of the hurricane passed into the Caribbean between the islands of Martinique and Saint Lucia as a Category 2 hurricane.[29] In the warm waters of the Caribbean, Dean rapidly strengthened into a Category 5 hurricane with 165 mph (266 km/h) sustained winds. An eyewall replacement cycle weakened Dean, which then passed just south of Jamaica as a category 4 hurricane. [30] Dean regained Category 5 status late on August 20 and at that strength it made landfall on the Yucatán Peninsula of Mexico near Costa Maya on August 21.[31] Dean weakened to a category one storm over land.
At least 42 people have been killed by Hurricane Dean (see Impact of Hurricane Dean). None of these deaths, however, have been attributed to its first landfall, as a Category 5 hurricane, likely because the landfall brought the heaviest storm surges onto sparsely-populated lands north of Chetumal Bay, including the Sian Ka'an Biosphere Reserve.
- See the NHC's advisory archive on Hurricane Dean.
- See the NHC's end-of-season report on Hurricane Dean.
[edit] Tropical Storm Erin
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| Duration | August 14 – August 17 | |||
| Intensity | 40 mph (65 km/h), 1003 mbar | |||
- Main article: Tropical Storm Erin (2007)
On August 9, an area of convection developed just south of Jamaica in association with a trough of low pressure.[32] The system tracked west-northwestward, and by August 10 consisted of a broad surface trough with minimal shower activity.[33] Convection increased on August 11,[34] and by August 12 the interaction between a tropical wave and an upper-level low in the area resulted in a large area of disorganized thunderstorms extending from the western Caribbean Sea into the central Bahamas.[35] Upper-level winds gradually became more beneficial for development, and on August 13 a broad low pressure area formed about 90 miles (145 km) north-northeast of Cancún, Quintana Roo.[36] Late on August 14, a reconnaissance flight into the system reported a small circulation center, but at the time was not well-defined enough to result in the initiation of tropical cyclone advisories. However, deep convection was maintained near the increasingly organizing center, and at 0300 UTC on August 15 the National Hurricane Center classified it as Tropical Depression Five about 425 miles (685 km) southeast of Brownsville, Texas.[37]
Based on reconnaissance data received from an NOAA plane investigating the depression, it was upgraded to Tropical Storm Erin on August 15.[38] It weakened to a tropical depression as it made landfall near Lamar, Texas, on August 16,[39] and the NHC issued its last advisory on the system shortly thereafter as it moved inland, and the HPC dropped the system as a tropical depression when it lost its surface wind circulation on the afternoon of August 19.[40]
Two people were killed when a warehouse collapsed in Texas.[41] In total, 16 people died as a result of Erin. Damage was estimated at $25 million.
- See the NHC's advisory archive on Tropical Storm Erin.
- See the HPC's advisory archive on Tropical Storm Erin.
- See the NHC's end-of-season report on Tropical Storm Erin.
[edit] Hurricane Felix
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| Duration | August 31 – September 6 | |||
| Intensity | 175 mph (280 km/h), 929 mbar | |||
- Main article: Hurricane Felix (2007)
On August 31, an area of disturbed weather east of the Windward Islands was numbered Tropical Depression Six after satellite imagery showed that a tropical low had formed.[42] Early on September 1, it was upgraded to a tropical storm and named Felix. Later that day, Felix was upgraded to a hurricane. On September 2, Felix was upgraded to a major hurricane. It rapidly intensified into a Category 5 storm by the end of the evening, and after briefly weakening to Category 4 status Felix again restrengthened and struck northeastern Nicaragua with winds of 160 mph (260 km/h) on September 4. (See Impact of Hurricane Felix). It rapidly weakened over land and the last advisory was issued on September 5. At least 133 people were killed by Hurricane Felix with another 70 others missing.
- See the NHC's advisory archive on Hurricane Felix.
- See NHC's end-of-season report on Hurricane Felix.
[edit] Tropical Storm Gabrielle
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| Duration | September 8 – September 11 | |||
| Intensity | 60 mph (95 km/h), 1004 mbar (hPa) | |||
- Main article: Tropical Storm Gabrielle (2007)
A cold front that moved off the southeastern coast of the United States on September 1 developed a weak low over the waters near Georgia. The low drifted eastward and weakened over the next few days until it joined with convection from an upper-level trough that had been moving over the western Atlantic.[43] An Air Force Reserve Hurricane Hunter investigating the low on September 7 was unable to find a well-defined circulation, but did find evidence of tropical storm-force surface winds. Subsequent satellite imagery from that evening discovered a broad and elongated low, indicating that Subtropical Storm Gabrielle had formed about 360 nautical miles (670 km) southeast of Cape Hatteras.[44]
For the next twelve hours, the system's strongest winds and thunderstorms remained well to the north of the center. On September 8 new convection eventually united with the center, leading the transition of Gabrielle into a tropical storm. Gabrielle gradually strengthened as it travelled northwest towards North Carolina and Virginia. The storm reached its peak intensity of 60 mph (95 km/h) just before it arrived in Cape Lookout, though strong wind shear kept most of the convection and surface winds offshore.[43] Gabrielle weakened over land, and moved back into the Atlantic on September 10. The circulation deteriorated further, and the storm dissipated southwest of Nova Scotia the next day.[45] Damages in eastern North Carolina were very light, and there were no casualties associated with this system.
- See the NHC's advisory archive on Tropical Storm Gabrielle.
- See NHC's end-of-season report on Tropical Storm Gabrielle.
[edit] Tropical Storm Ingrid
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| Duration | September 12 – September 17 | |||
| Intensity | 45 mph (75 km/h), 1002 mbar (hPa) | |||
- Main article: Tropical Storm Ingrid (2007)
A large, westward-moving tropical wave moved off the coast of Africa on September 6. Strong easterly shear inhibited its development until the 9th, when it developed a broad area of low pressure in the mid-tropical Atlantic.[46] By the morning of September 12, the shear had weakened, allowing the system to organize into Tropical Depression Eight about 980 nautical miles (1,810 km) east of the Lesser Antilles.
The depression moved west-nortwestward for the next week, steering along the southern edge of a mid-tropospheric ridge. Unfavorable conditions caused by moderate westerly shear inhibited the storm's initial development. Despite this, the cyclone slowly developed into a weak tropical storm on September 13, and reached its maximum intensity the next day.[46] The shearing winds from a tropical upper tropospheric trough persisted over the cyclone, returning Ingrid to a depression on September 15. The final advisory was issued on the 17th as the system degenerated into an open wave north of the Leeward Islands.[47] There were no reports of damage or casualties associated with Ingrid because the storm never threatened land.
- See the NHC's advisory archive on Tropical Storm Ingrid.
- See NHC's end-of-season report on Tropical Storm Ingrid.
[edit] Hurricane Humberto
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| Duration | September 12 – September 14 | |||
| Intensity | 90 mph (150 km/h), 985 mbar | |||
- Main article: Hurricane Humberto (2007)
On September 8, weak surface trough and an upper-level low produced disorganized showers and thunderstorms between western Cuba and the eastern Gulf of Mexico.[48] The area of thunderstorms continued to move west-northwestward across the Gulf of Mexico and on September 12 thunderstorms organized enough to be classified as Tropical Depression Nine about 60 miles (100 km) southeast of Matagorda, Texas.[49] [50] The depression quickly intensified, and within three hours of forming, it became Tropical Storm Humberto.[51] Humberto turned to the north and eventually north-northeast and continued to rapidly intensify. In the early morning hours of September 13, Hurricane Hunter aircraft found that Humberto had strengthened into a hurricane while located about 15 miles (20 km) off the coast of Texas. [52] Around 0700 UTC (3 a.m. CDT), Hurricane Humberto made landfall near High Island, Texas as a category 1 hurricane.[53] Humberto quickly weakened and entered Southwest Louisiana as a tropical storm during the afternoon of September 13. [54]
Hurricane Humberto caused some structural damage on High Island and widespread tree and power line damage in the Beaumont-Port Arthur area.[55] Power outages caused four oil refineries to halt production in Beaumont. One person was reported dead as a result of the storm, a Bridge City man killed when his carport crashed on him outside his house. Damage was estimated at $50 million.[55]
- See the NHC's advisory archive on Hurricane Humberto.
- See the HPC's advisory archive on Tropical Depression Humberto.
- See NHC's end-of-season report on Hurricane Humberto.
[edit] Tropical Depression Ten
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| Duration | September 21 – September 22 | |||
| Intensity | 35 mph (55 km/h), 1005 mbar | |||
- Main article: Tropical Depression Ten (2007)
An extratropical low formed off the east coast of Florida on September 18. It slowly tracked westward, breaking itself away from a trough over the Atlantic while crossing the Florida Peninsula on September 19, emerging in the Gulf of Mexico on September 20. It slowly organized itself and was classified as a subtropical depression on the morning of September 21 just south of the Florida Panhandle. Three hours later, it was reclassified as fully tropical. At 8 pm EDT (0000 UTC) later that day, Tropical Depression Ten began to move onshore, and never reached tropical storm strength.
Damage from the precursor low was reported in Eustis, Florida from one or more tornadoes that damaged or destroyed about 50 houses, but caused no serious injuries.[56] No deaths were reported from the tornado, and damage totaled $6.2 million.
- See the NHC's advisory archive on Tropical Depression Ten.
- See NHC's end-of-season report on Tropical Depression Ten.
[edit] Tropical Storm Jerry
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| Duration | September 23 – September 24 | |||
| Intensity | 40 mph (65 km/h), 1003 mbar (hPa) | |||
- Main article: Tropical Storm Jerry (2007)
Jerry began as a non-tropical low that drifted around the central North Atlantic on September 21. Convection gradually developed and wrapped around the low. Given that the system was involved with an upper-level low, and that the convection and strongest winds were distant from the center, it was classified as a subtropical depression on September 23 about 1060 miles (1710 kilometers) west of the Azores.[57][58] The storm was poorly organized and lacked a well-defined inner core; but later that day, satellite intensity observations and QuikScat data estimated that it had intensified into a subtropical storm.[59]
Jerry became fully tropical on September 24 when deep convection developed near the center and the radius of maximum winds decreased.[57] Thereafter, the storm tracked northeastward over cooler waters and began to weaken. Jerry accelerated ahead of a strong cold front, and the circulation opened up into a sharp trough. By September 25 the storm had completely dissipated. Since Jerry remained far from land throughout its short life, there were no reports of casualties or damages associated with the system.[57]
- See the NHC's archive history on Tropical Storm Jerry.
- See NHC's end-of-season report on Tropical Storm Jerry.
[edit] Hurricane Karen
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| Duration | September 25 – September 29 | |||
| Intensity | 75 mph (120 km/h), 988 mbar (hPa) | |||
- Main article: Hurricane Karen (2007)
A very large tropical wave accompanied by a large envelope of low pressure emerged from the coast of Africa on September 21. As it moved westward, deep convection gradually increased over the disturbance as its broad low-level circulation became better-defined. By September 24, as the system traveled northwestward it organized enough to become a tropical depression.[60] Six hours later the depression was upgraded to Tropical Storm Karen.[61]
Karen's organization and intensity remained steady for the next day. Early on the 26th, however, the storm strengthened significantly. In post-operational analysis the cyclone was determined to have reached hurricane-strength for about twelve hours.[60] The strengthening was short-lived because a sharp upper-level trough to the west of Karen increased the amount of vertical wind shear over the hurricane. By September 28 these unfavorable conditions had weakened Karen to a marginal tropical storm and left its low-level circulation exposed.[62] Meanwhile, the storm began heading northward and experiencing intermittent bursts of deep convection. However, the relentless wind shear exposed the system's circulation until it dissipated in the mid-Atlantic on September 29. Karen's remnants lingered near the Leeward Islands for the next few days, although the system never directly affected land. As a result, no reported damages or casualties were associated with Karen.[60]
- See the NHC's archive history on Hurricane Karen.
- See NHC's end-of-season report on Hurricane Karen.
[edit] Hurricane Lorenzo
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| Duration | September 25 – September 28 | |||
| Intensity | 80 mph (130 km/h), 990 mbar (hPa) | |||
- Main article: Hurricane Lorenzo (2007)
A tropical wave moved off the western coast of Africa on September 11,[63] traversed the Caribbean and crossed the Yucatán on September 21. The disturbance developed a small surface low on the 24th while moving erratically over the southwestern Gulf of Mexico.[63] Strong upper-level winds initially prevented the system from developing convection; however, it relaxed on the following day and convection increased.[64][63] On the evening of September 25, a Hurricane Hunter aircraft found evidence that the low qualified as a tropical depression.[65]
Under weak steering currents, the depression drifted south and southwest, executing a small cyclonic loop into the Bay of Campeche. Upper-level winds gave way to an anticyclone above the depression, and the system became a Tropical Storm Lorenzo on September 27 about 130 nautical miles (240 km) east of Tuxpan.[63] Rapid intensification brought Lorenzo to hurricane status early that evening, less than twelve hours after becoming a tropical storm. Lorenzo reached its peak intensity on September 28, then weakened slightly before making landfall near Tecolutla, Mexico as a minimal hurricane. The small circulation weakened rapidly after landfall, and the system dissipated the next day.[63]
Six deaths in Mexico were attributable to Lorenzo; mostly attributable to flash floods and mudslides. The states of Puebla and Veracruz reported damage from rain and high winds. Two hundred people were forced to evacuate in Hidalgo when the San Lorenzo River overflowed its banks. Lorenzo made landfall in virtually the same location that Hurricane Dean had struck a month earlier.[63]
- See the NHC's advisory archive on Hurricane Lorenzo.
- See NHC's end-of-season report on Hurricane Lorenzo.
[edit] Tropical Storm Melissa
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| Duration | September 28 – September 30 | |||
| Intensity | 40 mph (65 km/h), 1005 mbar (hPa) | |||
- Main article: Tropical Storm Melissa (2007)
Melissa began as a tropical wave that exited the western coast of Africa on September 26. The next day an area of low pressure developed near the Cape Verde islands, and the system soon organized into Tropical Depression Fourteen on September 28.[66] The depression drifted westward between very weak steering currents. Ordinarily a system would be steered along the edge of a subtropical ridge, but a low pressure system over the northeastern Atlantic subdued its development.[67]
While inching westward, the depression strengthened slightly and became Tropical Storm Melissa on September 29, tying the record for most tropical storms to form in a month.[68] The next day increasing westerly shear weakened Melissa back to a tropical depression. As it lost deep convection, the depression moved rapidly toward the west-northwest along the southern edge of a regenerating low-level ridge.[67] Thunderstorm activity sputtered, and the depression degenerated to a remnant low on the 30th about 475 nautical miles (880 km) west of the Cape Verde Islands. The low tracked along the low-level ridge for the several days, and merged with a frontal zone northeast of the Leeward Islands on October 5. Since Melissa did not affect land, there were no reports of damage or casualties associated with the storm.[67]
- See the NHC's archive history on Tropical Storm Melissa.
- See NHC's end-of-season report on Tropical Storm Melissa.
[edit] Tropical Depression Fifteen
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| Duration | October 11 – October 12 | |||
| Intensity | 35 mph (55 km/h), 1011 mbar (hPa) | |||
Tropical Depression Fifteen formed from a large and complex area of disturbed weather that extended from the Caribbean Sea into the western Atlantic. On October 8 the eastern end of the system formed a surface low and gradually developed convection as it moved northeastward. It is possible that the system's formation was helped by the remains of Hurricane Karen.[69] While 645 nmi (1,195 km) southeast of Bermuda the system was sufficiently organized to declare it a tropical depression on October 11. The depression maintained its intensity while an upper-level trough moved through the area. In its wake the cyclone was left with hostile conditions, including strong northerly wind shear.[70] The depression weakened to a remnant low on October 12 and merged with a frontal zone two days later. The resulting extratropical low strengthened slightly until it was absorbed by a larger extratropical system north of the Azores on October 17.[69] Because the system remained far from land, no damages were reported.
- See the NHC's advisory archive on Tropical Depression Fifteen.
- See NHC's end-of-season report on Tropical Depression Fifteen.
[edit] Hurricane Noel
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| Duration | October 28 – November 2 | |||
| Intensity | 80 mph (130 km/h), 980 mbar | |||
- Main article: Hurricane Noel (2007)
During the evening of October 27, a low pressure system that had been slowly developing over the eastern Caribbean gained enough organization to be declared Tropical Depression Sixteen. It steadily intensified and became a tropical storm on the afternoon of October 28. It made landfall in Haiti on October 29, and then meandered across the western Caribbean near Cuba for the next three days. Noel brought torrential rain to the region, killing at least 168 people. It then accelerated northeastward, passing through the Bahamas before strengthening to a hurricane on November 1. Noel began an extratropical transition on November 2. While sustained winds were still at category 1 strength, the NHC issued its final advisory that afternoon. The Canadian Hurricane Centre issued ongoing advisories every three hours on Post-tropical Storm Noel as it approached Canada's eastern provinces until it completed its transition to being fully extratropical on November 4 while over Labrador, shortly before it crossed back into the Atlantic, heading towards West Greenland.
- See the NHC's advisory archive on Hurricane Noel.
- See the NHC's end-of-season report on Hurricane Noel.
[edit] Tropical Storm Olga
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