The 2017 Atlantic hurricane season is an ongoing event in the annual formation of tropical cyclones in the Atlantic basin. The season has been very active, the most active since 2005 in terms of ACE. The season is also one of only six years to feature at least two Category 5 hurricanes: Hurricane Irma and Hurricane Maria. Along with 2007, Maria's landfall on Dominica also makes 2017 the second season on record to feature two hurricanes making landfall at Category 5 intensity. In addition, Irma was the strongest hurricane ever recorded to form in the Atlantic Ocean outside of the Gulf of Mexico and Caribbean Sea.
The season officially began on June 1 and will end on November 30. These dates historically describe the period of year when most tropical cyclones form in the Atlantic basin and are adopted by convention. However, as shown by Tropical Storm Arlene in April, the formation of tropical cyclones is possible at other times of the year. In mid-June, Tropical Storm Bret struck the island of Trinidad, which is rarely impacted by tropical cyclones due to its low latitude. A few weeks later, Tropical Storm Cindy struck the state of Louisiana. In late August, Hurricane Harvey became the first major hurricane to make landfall in the United States since Wilma in 2005, while also setting the record for most rainfall dropped by a tropical cyclone in the nation. In early September, Hurricane Irma, a Cape Verde-type hurricane, became the first Category 5 hurricane to impact the northern Leeward Islands on record, as well as equaling the strongest hurricane ever to make landfall in the Atlantic basin—the 1935 Labor Day hurricane. With Hurricane Maria striking Puerto Rico as a Category 4, the season was the first on record to feature three Atlantic hurricanes making landfall anywhere in the United States at Category 4 intensity or stronger.
Beginning 2017, the National Hurricane Center (NHC) has the option to issue advisories, and thus allow watches and warnings to be issued, on disturbances that are not yet tropical cyclones but have a high chance to become one, and are expected to bring tropical storm or hurricane conditions to landmasses within 48 hours. Such systems are termed "potential tropical cyclones". Advisories on these storms contain the same content, including track forecasts and cyclone watches and warnings, as advisories on active tropical cyclones. This was first demonstrated on June 18 with the designation of Potential Tropical Cyclone Two, which later developed into Tropical Storm Bret, east-southeast of the Windward Islands.
|Record high activity||28||15||7|
|Record low activity||4||2†||0†|
|TSR||December 13, 2016||14||6||3|
|TSR||April 5, 2017||11||4||2|
|CSU||April 6, 2017||11||4||2|
|TWC||April 17, 2017||12||6||2|
|NCSU||April 18, 2017||11–15||4–6||1–3|
|TWC||May 20, 2017||14||7||3|
|NOAA||May 25, 2017||11–17||5–9||2–4|
|TSR||May 26, 2017||14||6||3|
|CSU||June 1, 2017||14||6||2|
|UKMO||June 1, 2017||13*||8*||N/A|
|TSR||July 4, 2017||17||7||3|
|CSU||July 5, 2017||15||8||3|
|CSU||August 4, 2017||16||8||3|
|TSR||August 4, 2017||17||7||3|
|NOAA||August 9, 2017||14–19||5–9||2–5|
|* June–November only.
† Most recent of several such occurrences. (See all)
Ahead of and during the season, several national meteorological services and scientific agencies forecast how many named storms, hurricanes and major (Category 3 or higher on the Saffir–Simpson scale) hurricanes will form during a season and/or how many tropical cyclones will affect a particular country. These agencies include the Tropical Storm Risk (TSR) Consortium of the University College London, the National Oceanic and Atmospheric Administration (NOAA) and Colorado State University (CSU). The forecasts include weekly and monthly changes in significant factors that help determine the number of tropical storms, hurricanes, and major hurricanes within a particular year. Some of these forecasts also take into consideration what happened in previous seasons and the dissipation of the 2014–16 El Niño event. On average, an Atlantic hurricane season between 1981 and 2010 contained twelve tropical storms, six hurricanes, and two major hurricanes, with an Accumulated Cyclone Energy (ACE) index of between 66 and 103 units.
The first forecast for the year was issued by TSR on December 13, 2016. They anticipated that the 2017 season would be a near-average season, with a prediction of 14 named storms, 6 hurricanes, and 3 major hurricanes. They also predicted an ACE index of around 101 units. On December 14, CSU released a qualitative discussion detailing five possible scenarios for the 2017 season, taking into account the state of the Atlantic Multidecadal Oscillation and the possibility of El Niño developing during the season. TSR lowered their forecast numbers on April 5, 2017 to 11 named storms, 4 hurricanes, and 2 major hurricanes, based on recent trends favoring the development of El Niño. The next day, CSU released their prediction, also predicting a total of 11 named storms, 4 hurricanes, and 2 major hurricanes. On April 17, The Weather Company released their forecasts, calling for 2017 to be a near-average season, with a total of 12 named storms, 6 hurricanes, and 2 major hurricanes. The next day, on April 18, North Carolina State University released their prediction, also predicting a near-average season, with a total of 11–15 named storms, 4–6 hurricanes, and 1–3 major hurricanes. On May 20, The Weather Company issued an updated forecast, raising their numbers to 14 named storms, 7 hurricanes, and 3 major hurricanes to account for Tropical Storm Arlene as well as the decreasing chance of El Niño forming during the season. On May 25, NOAA released their prediction, citing a 70% chance of an above average season due to "a weak or nonexistent El Niño", calling for 11–17 named storms, 5–9 hurricanes, and 2–4 major hurricanes. On May 26, TSR updated its prediction to around the same numbers as its December 2016 prediction, with only a minor change in the expected ACE index amount to 98 units.
CSU updated their forecast on June 1 to include 14 named storms, 6 hurricanes and 2 major hurricanes to include Tropical Storm Arlene. It was based on the current status of the North Atlantic Oscillation, which was showing signs of leaning towards a negative phase, favoring a warmer tropical Atlantic; and the chances of El Niño forming were significantly lower. However, they stressed on the uncertainty that the El Niño–Southern Oscillation could be in a warm-neutral phase or weak El Niño conditions by the peak of the season. On the same day, the United Kingdom Met Office (UKMO) released its forecast of a very slightly above-average season. It predicted 13 named storms with a 70% chance that the number would be in the range 10 to 16 and 8 hurricanes with a 70% chance that the number would be in the range 6 to 10. It also predicted an ACE index of 145 with a 70% chance that the index would be between 92 and 198. On July 4, TSR released their fourth forecast for the season, increasing their predicted numbers to 17 named storms, 7 hurricanes, and 3 major hurricanes, due to the fact that El Niño conditions would no longer develop by the peak of the season and the warming of sea-surface temperatures across the basin. Additionally, they predicted a revised ACE index of 116 units. During August 9, NOAA released their final outlook for the season, raising their predictions to 14–19 named storms, though retaining 5–9 hurricanes and 2–5 major hurricanes. They also stated that the season has the potential to be extremely active, possibly the most active since 2010.
The accumulated cyclone energy (ACE) index for the 2017 Atlantic hurricane season, as of 03:00 UTC on September 25, is 182.005 units,[nb 1] which is the most ACE for an Atlantic hurricane season since 2005, and nearly double the 1981–2010 full-season median of 92. With an ACE value under 4 units following the dissipation of Emily, 2017 set the record for lowest ACE produced by a season's first five named storms.
A potent extratropical cyclone formed well east of Bermuda on April 16. The cyclone moved southeast, becoming disconnected from the surrounding environment and gradually losing its frontal characteristics. Deep convection formed in bands north and east of the center by 00:00 UTC on April 19, leading to the formation of a subtropical depression. Despite an unfavorable environment, with ocean temperatures near 20 °C (68 °F) and moderate wind shear, convection coalesced near the center and allowed the subtropical depression to become fully tropical by 00:00 UTC on April 20. It intensified into Tropical Storm Arlene six hours later. After attaining peak winds of 50 mph (85 km/h), the storm began to rotate around a larger extratropical low. The storm tracked into the cold sector of the cyclone, causing Arlene to lose tropical characteristics around 12:00 UTC on April 21. The post-tropical cyclone moved south and east, before dissipating well west-southwest of the Azores on April 22.
Upon its formation as a subtropical depression on April 19, Arlene was the sixth known subtropical or tropical cyclone to form in the month of April in the Atlantic basin; the other instances were Ana in 2003, a subtropical storm in April 1992, and three tropical depressions in 1912, 1915, and 1973, respectively. When Arlene became a tropical storm on April 20, this marked only the second such occurrence on record, after Ana in 2003.[nb 2] Furthermore, it had the lowest central pressure of any Atlantic storm recorded in the month of April, with a central pressure of 990 mbar (hPa; 29.23 inHg), again surpassing Ana. Additionally, unrelated to Arlene, Tropical Storm Adrian in the Eastern Pacific basin also formed before the corresponding hurricane season was set to officially begin, being the earliest named storm in the Eastern Pacific proper. The last time where the first storms in both basins were pre-season storms was in 2012.
A tropical wave moved off the coast of Africa on June 13 and was first monitored by the National Hurricane Center shortly afterwards. Development, however, was expected to be slow due to its low latitude and relatively fast motion. As it moved swiftly across the Main Development Region of the Atlantic Ocean, the disturbance began to gradually organize, and the NHC raised development chances slightly on June 16. Little change in organization occurred until June 18, at which point a burst of convection near the center of the disturbance prompted the NHC to designate the system as Potential Tropical Cyclone Two at 21:00 UTC. This was the agency's first designation of a disturbance that had not yet developed into a tropical cyclone. The storm continued to organize as it accelerated towards Venezuela and Trinidad and Tobago throughout the night, with banding features becoming evident. Later on June 19, the system developed a closed low-level circulation and was upgraded to Tropical Storm Bret at 21:00 UTC. One day later, at 21:00 UTC on June 20, the last advisory on Bret was issued following its degeneration into a tropical wave.
According to Phil Klotzbach of Colorado State University, Bret was the earliest storm to form in the Main Development Region on record, surpassing a record set by Tropical Storm Ana in 1979. Bret was also the lowest latitude named storm in the month of June since 1933 at 9.4°N. In Trinidad, one person died after he slipped and fell while running across a makeshift bridge; the fatality is considered indirectly related to Bret. Another fatality occurred in Tobago after a man's house collapsed on him; he eventually succumbed to his injuries a week later.
The NHC first began monitoring the potential for tropical cyclone formation over the northwestern Caribbean Sea on June 13. A large area of disturbed weather developed within the region three days later, and it slowly organized while entering the central Gulf of Mexico, prompting the NHC to begin advisories on a potential tropical cyclone on June 19. The structure of the system was initially sprawling, with tropical storm-force winds well displaced from a broad area of low pressure with embedded swirls. A reconnaissance aircraft investigating the system around 18:00 UTC the following day was able to pinpoint a well-defined center, indicating the formation of Tropical Storm Cindy. Despite the presence of dry air and strong wind shear, the cyclone still managed to attain peak winds of 60 mph (95 km/h) before weakening on approach to the Louisiana coastline. It made landfall between Port Arthur, Texas and Cameron, Louisiana early on June 22 and weakened while progressing inland.
A state of emergency was declared for Biloxi, Mississippi in anticipation of flooding. A ten-year-old boy died from injuries sustained during the storm in Fort Morgan, Alabama. A second fatality later occurred in Bolivar Peninsula, Texas.
Early on June 29, the NHC began tracking a tropical wave embedded within a large envelope of deep moisture across the coastline of western Africa. The disturbance was introduced as a potential contender for tropical cyclone formation two days later, as environmental conditions were expected to favor slow organization. It began to show signs of organization over the central Atlantic early on July 3, but the chances for development began to decrease two days later as the system moved toward a more stable environment. Having already acquired a well-defined circulation, the development of a persistent mass of deep convection around 03:00 UTC the following day prompted the NHC to upgrade the wave to Tropical Depression Four, located about 1,545 miles (2,485 km) east of the Lesser Antilles. Despite wind shear being low, the nascent depression struggled to intensify due to a dry environment caused by a Saharan Air Layer to its east, causing the low-level circulation to weaken, and resulting in the tropical depression degenerating into an open trough late the next day.
Late on July 15, the NHC highlighted a low-pressure trough over the central Atlantic as having the potential to develop into a tropical cyclone in the coming days. The disturbance began to show signs of organization early on July 17, and data from a reconnaissance aircraft investigating the system confirmed the development of Tropical Storm Don around 21:00 UTC that day. The storm's overall appearance improved over subsequent hours up until around 09:00 UTC, as a central dense overcast, accompanied by significant clusters of lightning, became pronounced. Don attained its peak intensity at this time, characterised by winds of approximately 50 mph (85 km/h). The next plane to investigate the cyclone a few hours later, however, found that the system's center had become less defined, and that sustained wind speeds had decreased to about 40 mph (65 km/h). A combination of reconnaissance data and surface observations from the Windward Islands indicated that Don opened up into a tropical wave around 03:00 UTC on July 19 as it entered the eastern Caribbean Sea.
In late July, a dissipating cold front extended into the northeastern Gulf of Mexico, where the NHC began forecasting the development of an area of low pressure over the next day on July 30. Any development was expected to be slow due to land proximity and marginal upper-level winds. Contrary to predictions, a rapid period of organization occurred over the next 24 hours and the system was deemed as Tropical Depression Six at 09:00 UTC on July 31, strengthening into Tropical Storm Emily just two hours later. After attaining its peak intensity with winds of 45 mph (75 km/h) and a minimum pressure of 1,005 mbar (29.7 inHg), Emily made landfall on Anna Maria Island around 14:45 UTC. Weakening quickly ensued, and later that day the circulation of Emily became elongated as it was downgraded to a tropical depression. The increasingly disrupted system later moved off the First Coast of Florida into the western Atlantic early the next day, accelerating northeastwards before becoming embedded within a frontal zone early on August 2.
Following the classification of Tropical Storm Emily, Florida Governor Rick Scott declared a state of emergency for 31 counties to ensure residents were provided with the necessary resources. The storm spawned an EF0 tornado near Bradenton. The tornado was on the ground for about 1.3 mi (2.1 km) and destroyed two barns and a few greenhouses, while an engineered wall collapsed, leaving about $96,000 in damage. On August 1, torrential rains related to Emily impacted parts of Miami Beach, with accumulations reaching 6.97 in (177 mm) in 3.5 hours, of which 2.17 in (55 mm) fell in just 30 minutes. Coinciding with high tide the deluge overwhelmed flood pumps, with three of them shutting down due to lightning-induced power outages, and resulted in significant flash floods. Multiple buildings suffered water damage, with some having 2.5 ft (0.76 m) of standing water. One person was hospitalized after becoming stuck in flood waters. Portions of Downtown Miami, such as Brickell, were also heavily affected; numerous vehicles became stranded in flooded roadways.
The NHC began tracking a tropical wave in the southeastern Caribbean Sea for possible development on August 3. After organizing for a few days, advisories were initiated on Potential Tropical Cyclone Seven at 21:00 UTC on August 6. The disturbance became Tropical Storm Franklin at 03:00 UTC on August 7. After strengthening into a moderate tropical storm, Franklin made its first landfall near Pulticub, Mexico at 03:00 UTC on August 8. The cyclone weakened considerably while over the peninsula, however its satellite presentation remained well-defined, with the inner core tightening up considerably. Later that day, Franklin emerged into the Bay of Campeche, and immediately began strengthening again, becoming a hurricane late on August 9. Five hours after peaking in intensity with winds of 85 mph (140 km/h) and a pressure of 981 mbar (28.97 inHg), Franklin made landfall in Lechuguillas, Mexico, and thereafter began to rapidly weaken. By 15:00 UTC on August 10, Franklin had dissipated as a tropical cyclone. However, its mid-level circulation remained intact and later contributed to the formation of Tropical Storm Jova in the Eastern Pacific early on August 12.
Immediately upon classification of Franklin as a potential tropical cyclone, tropical storm warnings were issued for much of the eastern side of the Yucatán Peninsula on August 6; a small portion of the coastline was upgraded to a hurricane watch with the possibility of Franklin nearing hurricane intensity as it approached the coastline the next night. Approximately 330 people were reported as going into storm shelters, and around 2,200 relocated from the islands near the coastline to farther inland in advance of the storm. In the Mexican part of the peninsula, damage was reported as having being minimal, mainly in Belize as the storm tracked slightly more northwards then expected, lessening impacts. Nonetheless, some areas received up to a foot of rain.
On August 2, the NHC began monitoring a tropical wave and its associated convection over the western coast of Africa. As the disturbance tracked west-northwest, its structure changed little in organization, but environmental conditions were expected to support the formation of a tropical cyclone. Instead, the system remained poorly defined and entered a less conducive environment east of the Leeward Islands. After progressing into the southwestern Atlantic several days later, the wave encountered more favorable upper-level winds and began to show signs of organization. Following the formation of a well-defined circulation, the disturbance was upgraded to a tropical depression at 03:00 UTC on August 13; by 21:00 UTC that afternoon, it intensified into Tropical Storm Gert. At 03:00 UTC on August 15, Gert intensified to a Category 1 hurricane with maximum sustained winds of 75 mph (120 km/h), making it the second hurricane of the season. Accelerating east-northeastwards, Gert peaked as a Category 2 system early on August 17 at an unusually high latitude of 40°N. Thereafter, Gert began to rapidly weaken as it exited the warm waters of the Gulf Stream. Just 12 hours after achieving peak intensity, Gert weakened below hurricane status and transitioned to an extratropical cyclone well east of Nova Scotia.
A tropical wave emerged off the western coast of Africa on August 13, coalescing into a potential tropical cyclone by 15:00 UTC on August 17. A reconnaissance aircraft investigating the system was able to locate a well-defined circulation, and the disturbance was upgraded to Tropical Storm Harvey accordingly six hours later. On a westward course into the Caribbean Sea, the storm was plagued by relentless wind shear, and it degenerated to an open tropical wave south of Hispaniola, by 03:00 UTC on August 20. Harvey's remnants continued into the Bay of Campeche, where more conducive environmental conditions led to the re-designation of a tropical depression, around 15:00 UTC on August 23, and subsequent intensification into a tropical storm by 04:00 UTC on the next morning. The cyclone began a period of rapid intensification shortly thereafter, attaining hurricane intensity by 17:00 UTC on August 24, Category 3 strength around 19:00 UTC on August 25, and Category 4 intensity by 23:00 UTC on that day.
Harvey crossed the shore between Port Aransas and Port O'Connor, Texas around 03:00 UTC on August 26, possessing maximum winds of 130 mph (215 km/h). The storm gradually spun down, becoming a tropical storm around 18:00 UTC on August 26, as it meandered across southeastern Texas. A light steering pattern caused the storm to emerge into the Gulf of Mexico on August 28, but a turn toward the north-northeast brought it ashore west of Cameron, Louisiana, as a weak tropical storm around 09:00 UTC on August 30. The system weakened to a tropical depression over central Louisiana late that day before losing tropical characteristics over central Tennessee early on September 1.
Rockport, Fulton, and the surrounding cities bore the brunt of Harvey's eyewall as it moved ashore in Texas. Numerous structures were heavily damaged or destroyed, boats were tossed or capsized, power poles were leant or snapped, and trees were downed. As debris covered roadways and cellphone service was compromised, communication to the hardest-hit locales was severed. One person was killed in Rockport after a fire began in his home, and approximately a dozen people were injured. Farther northeast, dire predictions of potentially catastrophic flooding came to fruition in Houston and nearby locales, where floodwaters submerged interstates, forced residents to their attics and roofs, and overwhelmed emergency lines. The National Weather Service tweeted, "This event is unprecedented & all impacts are unknown & beyond anything experienced..." At least 30 people were killed in the Houston area due to flooding. In addition to the flooding, Harvey spawned several tornadoes around Houston. Preliminary estimates place the damage caused by Harvey between $65 and $200 billion. Harvey killed 83 people, including 1 in Guyana and 82 in the United States. The storm produced 64.58 in (1,640 mm) of rainfall in Texas, the highest-ever rainfall total for any tropical cyclone in the United States and the third-highest rainfall total for a tropical cyclone in the Atlantic basin.[nb 3]
Harvey was the first major hurricane to strike the United States since Hurricane Wilma in 2005, ending the record-long drought that lasted 4,323 days. It is the most intense tropical cyclone to move ashore the mainland since Hurricane Charley in 2004, the first Category 4 hurricane to make landfall in Texas since Hurricane Carla in 1961.
A westward-moving tropical wave, first monitored over western Africa on August 26, organized into Tropical Storm Irma around 15:00 UTC on August 30. Amid an environment of low wind shear and warm ocean temperatures, the newly-formed cyclone moved generally westward while intensifying. A reconnaissance aircraft investigating the system east of the Caribbean on September 5 found the cyclone at Category 5 intensity. With a clear eye surrounded by a ring of extremely deep convection, Irma attained its peak intensity with winds of 185 mph (295 km/h) later that day, and maintained this intensity as it moved through the northern Leeward Islands. Some weakening occurred south of the Bahamas, but the cyclone regained Category 5 intensity before making landfall on the Sabana-Camagüey Archipelago of Cuba around 03:00 UTC on September 9. Land interaction disrupted the storm temporarily, but once again it strengthened to acquire winds of 130 mph (215 km/h), before making landfall in Cudjoe Key of the Florida Keys early on September 10. A few hours later, it struck Marco Island, Florida, with winds of 115 mph (185 km/h). Irma continued north and west, steadily weakening over the Southeastern United States before losing tropical characteristics in Georgia early on September 12.
With peak winds of 185 mph (295 km/h), Irma is the strongest Atlantic storm outside of the Gulf of Mexico or Caribbean Sea on record, and ties as the second most intense hurricane on record in the Atlantic. Maintaining peak intensity for 37 consecutive hours, Irma is the only tropical cyclone on record worldwide to have had winds that intense for so long. As the storm moved through the northern Leeward Islands, it became the only Category 5 to make a direct impact there; its landfall intensity ties it with the 1935 Labor Day hurricane as the strongest landfalling cyclone on record in the Atlantic. Two Category 4 hurricanes, Harvey and Irma, struck the United States in the span of two weeks; this marks the first time the country has suffered two landfalls of such intensity in the same hurricane season. Lastly, Irma accrued the third-highest Accumulated Cyclone Energy index on record.
In the aftermath of Irma, development on the islands of Barbuda and Saint Martin was described as being "95% destroyed" by respective political leaders, with 1,400 people feared homeless in Barbuda. So far, Irma has resulted in at least 102 deaths, including 44 across the Caribbean, and 58 in the United States.
A westward-moving tropical wave exited the west coast of Africa on August 31, organizing into Tropical Storm Jose over the open eastern Atlantic by 15:00 UTC on September 5. The quickly-strengthening cyclone attained hurricane intensity late on September 6, reached major hurricane strength late on September 7, and ultimately peaked as a Category 4 with winds of 155 mph (250 km/h) early on September 9. Moderate wind shear weakened the cyclone as it conducted a slow clockwise loop between Bermuda and the Caribbean Sea and eventually moved north ahead of an approaching trough. Steering currents collapsed by early on September 21, causing the system to stall offshore the Northeastern United States as a weakening tropical storm. With a rain shield in the northern and northwestern semicircles accompanied by a lack of deep convection over the center, the NHC declared Jose a post-tropical cyclone around 03:00 UTC on September 22, ending advisories once the storm's tropical storm-force winds moved off the New England coast at 21:00 UTC.
The government of Barbuda began efforts on September 8 to evacuate the entire island prior to Jose's anticipated arrival as most structures on the island had been heavily damaged or destroyed by Hurricane Irma.
A trough was present over the southwestern Gulf of Mexico on September 3, producing a widespread area of thunderstorms. Two days later, a distinct low pressure area formed about 50 mi (80 km) east of Tampico, Tamaulipas. At 21:00 UTC that day, the NHC designated the system as Tropical Depression Thirteen after an organized area of convection formed over the center. Located in an area of weak steering currents, the depression drifted slowly eastward. With gradually decreasing wind shear and warm water temperatures, the system intensified into Tropical Storm Katia on September 6, as the convection became better organized. Later that day, an aircraft reconnaissance flight into the storm found a partial eye wall and surface winds of 76 mph (122 km/h); on that basis, the NHC upgraded Katia to hurricane status. The convection organized into a central dense overcast as the system stalled. Late in the evening of September 8, Katia made landfall north of Tecolutla, Mexico as a weak Category 1 storm. The system rapidly dissipated over land on September 9. Katia's remnants traveled across Central America and later emerged over the Pacific Ocean, where redevelopment ensued. Tropical Depression Fifteen-E formed, which later strengthened into Hurricane Otis about a week later.
In preparation for Katia, over 4,000 residents were evacuated from the states of Veracruz and Puebla. Tourists left coastal towns, emergency shelters were opened, and storm drains were cleared before the onset of heavy rainfall. Two fatalities were reported in Xalapa from mudslides, while a third man was swept away by floodwaters in Jalcomulco. States of emergency were declared for 40 out of a total 53 municipalities that reported minor damage from mudslides and flooding. About 77,000 residents were left without power at the height of the storm.
A tropical wave moved off the coast of Africa on September 13. Contrary to predictions of only gradual organization over the following days, the system rapidly organized, becoming Tropical Depression Fourteen at 03:00 UTC on September 15. The NHC upgraded the system to Tropical Storm Lee at 15:00 UTC on the next day, based on an increase in deep convection and an advanced scatterometer (ASCAT) pass, which indicated that it was producing minimal tropical-storm-force winds. After encountering wind shear, Lee gradually weakened into a tropical depression early on September 17 before degenerating into a remnant low two days later. The NHC monitored the remnants of Lee intermittently for several days, but regeneration was not considered likely. However, the mid-level remnants of the cyclone became intertwined with an upper-level trough; a deep burst of convection led to a new surface circulation, and by 21:00 UTC on September 22, the system reorganized into a tropical depression and later that day a tropical storm. With an extremely small inner core, the storm was prone to sudden fluctuations in intensity. Lee underwent an unexpected period of rapid intensification overnight as a well-defined eye emerged, and at 06:30 UTC on September 24, Lee was upgraded to a Category 1 hurricane.
As of 5:00 a.m. AST (09:00 UTC) September 25, Hurricane Lee is located within 10 nautical miles of , about 910 miles (1,460 km) east of Bermuda, and about 1,355 miles (2,180 km) west-southwest of the Azores. Maximum sustained winds are 80 knots (90 mph; 150 km/h), a Category 1 on the Saffir–Simpson scale, with gusts to 100 knots (115 mph; 185 km/h). The minimum barometric pressure is 980 millibars (hPa; 28.94 inHg). The system is currently stationary. Lee is a very small hurricane, with hurricane-force winds extending outward up to 10 miles (20 km) from the center, and tropical storm-force winds extending outward up to 35 miles (55 km) from the center.
For latest official information, see:
Early on September 16, the NHC began monitoring a potential tropical cyclone. Later that day, it intensified into a tropical storm, which was named Maria. On September 17, an aircraft reconnaissance flight into the storm found an open eye wall and surface winds of 75 mph (120 km/h); on that basis, the NHC upgraded Maria to hurricane status. On September 18, Maria explosively intensified; over a 24-hour period, the hurricane's winds doubled from 80 mph (130 km/h; Category 1) to 160 mph (260 km/h; Category 5). Maria subsequently surpassed Irma the next day to become the most intense hurricane of the season by central pressure, with a minimum pressure of 908 millibars (26.81 inHg), although its sustained winds of 175 mph (280 km/h) did not surpass Irma's 185 mph (295 km/h) winds.
As of 5:00 a.m. EDT (09:00 UTC) September 25, Hurricane Maria is located within 20 nautical miles of , about 350 miles (560 km) south-southeast of Cape Hatteras, North Carolina. Maximum sustained winds are 70 knots (80 mph; 130 km/h), a Category 1 on the Saffir–Simpson scale, with gusts to 85 knots (100 mph; 165 km/h). The minimum barometric pressure is 957 millibars (hPa; 28.26 inHg). The system is moving north at 6 knots (7 mph; 11 km/h). Hurricane-force winds extend outward up to 70 miles (110 km) mainly to the east from the center of Maria, while tropical storm-force winds extended outward up to 230 miles (370 km).
For latest official information, see:
|Tropical Storm Warning
Tropical storm conditions expected within 36 hours.
|Tropical Storm Watch
Tropical storm conditions possible within 48 hours.
|Storm Surge Watch
Life-threatening inundation from storm surge possible within 48 hours.
A long-tracked tropical wave was designated as Potential Tropical Cyclone Ten, while it was located northeast of Florida on August 27. The NHC gave this disturbance a 90% chance of becoming a tropical cyclone within the next 48 hours. However, the system failed to attain any more tropical characteristics, and it began to undergo an extratropical transition. Consequently, the NHC issued its last advisory on the system at 21:00 UTC on August 29, declaring the system to be an extratropical low.
The following list of names will be used for named storms that form in the North Atlantic in 2017. Any retired names will be announced by the World Meteorological Organization in the spring of 2018. The names not retired from this list will not be used again until the 2023 season. This is the same list used in the 2011 season, with the exception of the name Irma, which replaced Irene; Irma was previously used in the 1978 season.
The usage of the name "Don" in July garnered some negative attention relating to United States President Donald Trump. Max Mayfield, former director of the National Hurricane Center, clarified that the name had no relation to Trump and was chosen in 2006 as a replacement for Dennis. Regardless, some outlets such as the Associated Press, "poked fun" at the name and Trump.
This is a table of all the storms that have formed in the 2017 Atlantic hurricane season. It includes their duration, names, affected areas, 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 the damage figures are in 2017 USD.
|Saffir–Simpson hurricane wind scale|