|Tropical storm (SSHWS/NWS)|
|Formed||June 14, 2018|
|Dissipated||June 19, 2018|
|Highest winds|| 1-minute sustained:65 mph (100 km/h)|
|Lowest pressure||997 mbar (hPa); 29.44 inHg|
|Fatalities||2 direct, 1 indirect|
|Areas affected||Central and Southern Mexico|
|Part of the 2018 Pacific hurricane season|
Tropical Storm Carlotta was a tropical cyclone that caused flooding within several states in southwestern and central Mexico. Carlotta formed as the result of a breakdown in the Intertropical Convergence Zone. On June 12, a broad area of low pressure formed several hundred miles south of Mexico and strengthened into a tropical storm by June 15. On the next day, the storm unexpectedly stalled within a favorable environment, which led to more intensification than originally anticipated. Early on June 17, Carlotta reached peak intensity with maximum sustained winds of 65 mph (100 km/h) and a minimum central pressure of 997 mbar (29.44 inHg) while located only 30 mi (50 km) south-southeast of Acapulco. The system then began to interact with land and experience wind shear, which resulted in the system weakening to tropical depression status later in the day. The storm weakened to a remnant low early on June 19 and dissipated several hours later.
A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain. Depending on its location and strength, a tropical cyclone is referred to by different names, including hurricane, typhoon, tropical storm, cyclonic storm, tropical depression, and simply cyclone. A hurricane is a tropical cyclone that occurs in the Atlantic Ocean and northeastern Pacific Ocean, and a typhoon occurs in the northwestern Pacific Ocean; in the south Pacific or Indian Ocean, comparable storms are referred to simply as "tropical cyclones" or "severe cyclonic storms".
Mexico, officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatemala, Belize, and the Caribbean Sea; and to the east by the Gulf of Mexico. Covering almost 2,000,000 square kilometres (770,000 sq mi), the nation is the fifth largest country in the Americas by total area and the 13th largest independent state in the world. With an estimated population of over 120 million people, the country is the tenth most populous state and the most populous Spanish-speaking state in the world, while being the second most populous nation in Latin America after Brazil. Mexico is a federation comprising 31 states and Mexico City, a special federal entity that is also the capital city and its most populous city. Other metropolises in the state include Guadalajara, Monterrey, Puebla, Toluca, Tijuana and León.
The Intertropical Convergence Zone (ITCZ), known by sailors as the doldrums or the calms because of its monotonous, windless weather, is the area where the northeast and southeast trade winds converge. It encircles Earth near the thermal equator, though its specific position varies seasonally. When it lies near the geographic Equator, it is called the near-equatorial trough. Where the ITCZ is drawn into and merges with a monsoonal circulation, it is sometimes referred to as a monsoon trough, a usage more common in Australia and parts of Asia.
Carlotta prompted the issuance of multiple watches and warnings for the southern coast of Mexico. The storm caused three deaths: two in Aguascalientes and one in Oaxaca, and flooding and landslides throughout the states of Aguascalientes, Guerrero, Michoacán, Oaxaca, Puebla, as well as the Yucatán Peninsula. Damage from the system was reported to be minor.
Aguascalientes, officially the Free and Sovereign State of Aguascalientes, is one of the 31 states which, with Mexico City, comprise the 32 Federal Entities of Mexico. It is divided into 11 municipalities and its capital city is Aguascalientes.
Oaxaca, officially the Free and Sovereign State of Oaxaca, is one of the 31 states which, along with Mexico City, make up the 32 federative entities of Mexico. It is divided into 570 municipalities, of which 418 are governed by the system of usos y costumbres with recognized local forms of self-governance. Its capital city is Oaxaca de Juárez.
Guerrero, officially the Free and Sovereign State of Guerrero, is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 81 municipalities and its capital city is Chilpancingo and its largest city is Acapulco.
Tropical Storm Carlotta formed as the result of a breakdown in the Intertropical Convergence Zone to the south of Mexico. A tropical wave that crossed over Central America around June 11 may have contributed to the storm's formation as well. 86 °F (30 °C), the depression experienced minimal change in intensity over the next 18 hours. After the system's center reformed farther north, the NHC reduced its intensity forecast as the storm would have less time over water. However, Carlotta never made landfall during its existence as a tropical cyclone. Around 18:00 UTC on June 15, the system strengthened into a tropical storm, after which it was assigned the name Carlotta. The system's intensity then leveled off for about twelve hours.On June 12, the Miami-based National Hurricane Center (NHC) reported that a broad area of low pressure had formed several hundred miles south of southeastern Mexico. The NHC continued to monitor the disturbance over the next couple days as it drifted northward. Initially, strong upper-level winds prevented development, but the system unexpectedly organized on June 14. Following structural improvements, the NHC upgraded the system into a tropical depression at 18:00 UTC while about 140 mi (220 km) south of Acapulco. Around that time, the NHC forecast that a mid-level ridge over Mexico would weaken on the next day, leaving the depression in an area of light steering currents. Despite being located in an environment with low to moderate wind shear and sea surface temperatures exceeding
Tropical waves, easterly waves, or tropical easterly waves, also known as African easterly waves in the Atlantic region, are a type of atmospheric trough, an elongated area of relatively low air pressure, oriented north to south, which moves from east to west across the tropics, causing areas of cloudiness and thunderstorms. West-moving waves can also form from the tail end of frontal zones in the subtropics and tropics, and may be referred to as easterly waves, but these waves are not properly called tropical waves; they are a form of inverted trough sharing many characteristics with fully tropical waves. All tropical waves form in the easterly flow along the equatorward side of the subtropical ridge or belt of high pressure which lies north and south of the Intertropical Convergence Zone (ITCZ). Tropical waves are generally carried westward by the prevailing easterly winds along the tropics and subtropics near the equator. They can lead to the formation of tropical cyclones in the north Atlantic and northeastern Pacific basins. A tropical wave study is aided by Hovmöller diagrams, a graph of meteorological data.
Central America is located on the southern tip of North America, or is sometimes defined as a subcontinent of the Americas, bordered by Mexico to the north, Colombia to the southeast, the Caribbean Sea to the east, and the Pacific Ocean to the west and south. Central America consists of seven countries: Belize, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, and Panama. The combined population of Central America has been estimated to be 41,739,000 and 42,688,190.
Miami, officially the City of Miami, is the cultural, economic and financial center of South Florida. Miami is the seat of Miami-Dade County, the most populous county in Florida. The city covers an area of about 56.6 square miles (147 km2), between the Everglades to the west and Biscayne Bay on the east; with a 2017 estimated population of 463,347, Miami is the sixth most densely populated major city in the United States. The Miami metropolitan area is home to 6.1 million people and the seventh-largest metropolitan area in the nation. Miami's metro area is the second-most populous metropolis in the southeastern United States and fourth-largest urban area in the U.S. Miami has the third tallest skyline in the United States with over 300 high-rises, 80 of which stand taller than 400 feet.
Early on June 16, Carlotta's forward motion began to fluctuate, changing from northeast to southeast in six hours.The storm began to intensify again around 06:00 UTC as it stalled off the coast of Mexico. Soon after, the cyclone began moving in a northerly direction. Over the next twelve hours, Carlotta experienced little change in organization before peaking at 00:00 UTC on June 17 with maximum sustained winds of 65 mph (100 km/h) and a minimum central pressure of 997 mbar (29.44 inHg) while located only 30 mi (50 km) south-southeast of Acapulco. Around that time, the NHC noted that the system's structure had improved significantly, with a contracting eye and more symmetric eyewall. Carlotta then began to weaken because of increasing interactions with land and northerly wind shear. Meanwhile, the system had begun tracking towards the northwest. Around 18:00 UTC on the same day, Carlotta weakened into a tropical depression after lacking organized deep convection for several hours. Over the next day, the depression continued to weaken before degenerating into a remnant low on June 19 at 00:00 UTC. Shortly after, Carotta's upper-level circulation decoupled entirely and drifted towards the southwest, while the low- and mid-level remnants remained. The system's remnants dissipated around 06:00 UTC while located offshore of the coast between Manzanillo and Zihuatanejo, Mexico.
The maximum sustained wind associated with a tropical cyclone is a common indicator of the intensity of the storm. Within a mature tropical cyclone, it is found within the eyewall at a distance defined as the radius of maximum wind, or RMW. Unlike gusts, the value of these winds are determined via their sampling and averaging the sampled results over a period of time. Wind measuring has been standardized globally to reflect the winds at 10 metres (33 ft) above the Earth's surface, and the maximum sustained wind represents the highest average wind over either a one-minute (US) or ten-minute time span, anywhere within the tropical cyclone. Surface winds are highly variable due to friction between the atmosphere and the Earth's surface, as well as near hills and mountains over land.
Atmospheric pressure, sometimes also called barometric pressure, is the pressure within the atmosphere of Earth. The standard atmosphere is a unit of pressure defined as 1013.25 mbar (101325 Pa), equivalent to 760 mm Hg (torr), 29.9212 inches Hg, or 14.696 psi. The atm unit is roughly equivalent to the mean sea-level atmospheric pressure on Earth, that is, the Earth's atmospheric pressure at sea level is approximately 1 atm.
The eye is a region of mostly calm weather at the center of strong tropical cyclones. The eye of a storm is a roughly circular area, typically 30–65 km (20–40 miles) in diameter. It is surrounded by the eyewall, a ring of towering thunderstorms where the most severe weather and highest winds occur. The cyclone's lowest barometric pressure occurs in the eye and can be as much as 15 percent lower than the pressure outside the storm.
On June 14 at 21:00 UTC, the government of Mexico issued a tropical storm watch for Tecpan de Galeana to Punta Maldonado. Six hours later, the watch was upgraded to a tropical storm warning. On June 15 at 15:00 UTC, the tropical storm warning was extended to Lagunas de Chacahua. Six hours later, the warning was discontinued for Tecpan de Galeana to west of Acapulco. On June 17 at 03:00 UTC, the warning was extended westward from Acapulco to Tecpan de Galeana and cancelled to the east of Punta Maldonado. At 09:00 UTC, the warning was discontinued east of Tecpan de Galeana and extended westward to Lazaro Cardenas. The tropical storm warning was cancelled at 18:00 UTC, after the storm weakened into a tropical depression.
Tropical Storm Carlotta caused flooding in southern Mexico, with the states of Aguascalientes, Guerrero, Michoacán, Oaxaca, Puebla, and the Yucatán Peninsula being affected. The storm caused two deaths in Aguascalientes and one in Oaxaca. In the Yucatán Peninsula, Carlotta, a tropical wave, and another low-pressure system dropped between 70–400 mm (3–20 in) of rain, causing severe flooding. In Tizimín, the Popolnáh police station was inundated and the DN-III-E Plan, a plan for the coordination of search and rescue operations and disaster aid, was activated to help with recovery efforts.
Michoacán, formally Michoacán de Ocampo, officially the Free and Sovereign State of Michoacán de Ocampo, is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. The State is divided into 113 municipalities and its capital city is Morelia. The city was named after José María Morelos, one of the main heroes of the Mexican War of Independence.
Puebla, officially the Free and Sovereign State of Puebla is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 217 municipalities and its capital is the city of Puebla.
The Yucatán Peninsula, in southeastern Mexico, separates the Caribbean Sea from the Gulf of Mexico, with the northern coastline on the Yucatán Channel. The peninsula lies east of the Isthmus of Tehuantepec, a northwestern geographic partition separating the region of Central America from the rest of North America. It is approximately 181,000 km2 (70,000 sq mi) in area, and is almost entirely composed of limestone.
In Oaxaca, severe flooding killed one individual. Fishermen recovered the body of a 29-year-old man about 10 mi (20 km) off the coast after he was dragged away by flood waters and drowned. The proximity of the storm prompted the closure of the ports of Huatulco, Puerto Ángel, and Puerto Escondido and the suspension of fishing operations; multiple landslides occurred in the state. In Guerrero, only minor damage occurred. In the Costa Chica region, the storm damaged several palapas on a beach and the fishing equipment of at least 80 families, preventing them from working. In the municipalities of Tecpan de Galeana, Zihuatanejo, and Petatlán, 42 homes were inundated by flood waters. A total of 138 trees were downed in Acapulco and several other municipalities. In Acapulco, a hospital sustained damage to its windows and four injuries were reported. Additionally, 32 neighborhoods lost power, nine houses lost their roofs, and 11 roads collapsed. In Tehuacán, Puebla, homes and businesses flooded, multiple cars were stranded, and several trees fell. Nearby, a state highway and a bridge collapsed, cutting off several towns in the area.
In Michoacán, multiple cities along the coast experienced severe flooding. In Melchor Ocampo, a peak rainfall total of 285.0 mm (11.2 in) occurred. Approximately 210.6 mm (8.291 in) of rain fell in La Villita while 194.9 mm (7.673 in) was recorded in Presa La Villita. Rainfall caused the Acalpican River to overflow its banks. In the Tiquicheo Municipality, 10 houses flooded after a river near the city overflowed its banks. Multiple homes were inundated in the Zamora Municipality. In Pátzcuaro, multiple landslides occurred, damaging roads in the region. In Nuevo Urecho, the overflow of the Los Hervores River damaged water pumps, resulting in a water shortage throughout the municipality. Throughout the storm, 35 temporary shelters were in operation in Michoacán.
In Aguascalientes, Carlotta caused infrastructural damage and two indirect deaths in Aguascalientes City. Rainfall from the system flooded streets, sweeping away dozens of cars and prompting the rescue of several people. Two women became entrapped in their vehicle because of rising flood waters and died of carbon monoxide poisoning. 57 mm (2.2 in) of rain fell, the city's drainage system collapsed; 12 trees fell and 12 houses were flooded. A waterspout touched down in the state. Mexican authorities alerted the public that the El Cedazo dam had the potential to overflow because of the heavy rainfall, although no overflow actually occurred.After
The 2007 Pacific hurricane season was a below-average Pacific hurricane season, featuring one major hurricane. The season officially started on May 15 in the eastern Pacific and on June 1 in the central Pacific, and ended on November 30; these dates conventionally delimit the period during which most tropical cyclones form in the region. The first tropical cyclone of the season, Alvin, developed on May 27, while the final system of the year, Kiko, dissipated on October 23. Due to unusually strong wind shear, activity fell short of the long-term average, with a total of 11 named storms, 4 hurricanes, and 1 major hurricane. At the time, 2007 featured the second-lowest value of the Accumulated cyclone energy (ACE) index since reliable records began in 1971. Two tropical cyclones – Cosme and Flossie – crossed into the central Pacific basin during the year, activity below the average of 4 to 5 systems.
The 2006 Pacific hurricane season was the most active since the 2000 season, producing produced 21 tropical depressions; 19 of which became tropical storms or hurricanes. The season officially started on May 15, 2006 in the eastern Pacific, designated as the area east of 140°W, and on June 1, 2006 in the central Pacific, which is between the International Date Line and 140°W, and lasted until November 30, 2006. These dates typically limit the period of each year when most tropical cyclones form in the eastern Pacific basin. This timeline documents all the storm formations, strengthening, weakening, landfalls, extratropical transitions, as well as dissipation. The timeline also includes information which was not operationally released, meaning that information from post-storm reviews by the National Hurricane Center, such as information on a storm that was not operationally warned on, have been included.
Hurricane Carlotta was the most powerful hurricane of the 2000 Pacific hurricane season. The third tropical cyclone of the season, Carlotta developed from a tropical wave on June 18 about 270 miles (470 km) southeast off the coast of Mexico. With favorable conditions for development, it strengthened steadily at first, followed by a period of rapid deepening to peak winds of 155 mph (250 km/h) on June 22. Cooler waters caused Carlotta to gradually weaken, and on June 25 it degenerated into a remnant area of low pressure while located about 260 miles (420 km) west-southwest of Cabo San Lucas.
Tropical Storm Julio in 2002 was a weak and short-lived tropical storm that made landfall along the southern Mexican coast. An area of convection organized into a tropical depression on September 25. Initially forecast to stay offshore, the depression headed northward and strengthened into a tropical storm that same day. Julio turned to the northwest and peaked as a minimal tropical storm just before landfall near Lázaro Cárdenas, on September 26. The storm soon weakened into a tropical depression and later on September 26, it rapidly dissipated over Mexico.
The 2013 Pacific hurricane season was the costliest Pacific hurricane season on record, with a total of about $4.2 billion in damages. The season produced above normal activity; however, the majority of the storms were weak. The season officially began on May 15, 2013 in the Eastern Pacific and started on June 1, 2013 in the Central Pacific. Both ended on November 30, 2013. These dates conventionally delimit the period of each year when most tropical cyclones form in the eastern Pacific basin. However, the formation of a storm is possible at any time.
The 2014 Pacific hurricane season was the fifth-busiest season since reliable records began in 1949, alongside the 2016 season. The season officially started on May 15 in the East Pacific Ocean, and on June 1 in the Central Pacific; they both ended on November 30. These dates conventionally delimit the period of each year when most tropical cyclones form in the Pacific basin.
The 2012 Pacific hurricane season was an above-average year in which seventeen named storms formed. The hurricane season officially began on May 15 with the formation of Tropical Storm Aletta in the East Pacific—defined as the region east of 140°W—and on June 1 in the central Pacific—defined as the region west of 140°W to the International Date Line—and ended on November 30 in both basins. These dates conventionally delimit the period during each year when most tropical cyclones form. The final cyclone of the year, Tropical Storm Rosa, dissipated on November 3.
Hurricane Erick brought minor impact to the western coastline of Mexico in July 2013. The fifth tropical cyclone and named storm, as well as the fourth hurricane of the annual hurricane season, Erick originated from a tropical wave that moved off the western coast of Africa on June 18. The wave tracked swiftly westward with little development, emerging into the eastern Pacific on July 1. As a result of favorable environmental conditions, the wave developed into a tropical depression on July 4, and further into Tropical Storm Erick at 0000 UTC on July 5. Steered generally west-northwest, Erick intensified into a Category 1 hurricane and reached its peak intensity with winds of 80 mph (130 km/h) on July 6. Its proximity to land and track over increasingly cooler waters caused the storm to deteriorate into a tropical storm the following day, though it remained at such intensity until degenerating into a remnant low early on July 9. The remnant circulation dissipated a few hours later, southwest of Baja California Sur.
Hurricane Raymond was the only major hurricane in the eastern Pacific in 2013 and briefly threatened the southwestern coast of Mexico before recurving back out to sea. The seventeenth named storm and eighth hurricane of the annual cyclone season, Raymond developed from a tropical wave on October 20 south of Acapulco, Mexico. Within favorable conditions for tropical cyclone development, Raymond quickly intensified, attaining tropical storm intensity and later hurricane intensity within a day of cyclogenesis. On October 21, the hurricane reached its peak intensity with winds of 125 mph (205 km/h). A blocking ridge forced the hurricane to the southwest, while at the same time Raymond began to quickly weaken due to wind shear. The following day, the tropical cyclone weakened to tropical storm status. After tracking westward, Raymond reentered more favorable conditions, allowing it to intensify back to hurricane strength on October 27 while curving northward. The hurricane reached a secondary peak intensity with winds of 105 mph (165 km/h) several hours later. Deteriorating atmospheric conditions resulted in Raymond weakening for a final time, and on October 30, the National Hurricane Center (NHC) declared the tropical cyclone to have dissipated.
Hurricane Cosme caused flooding along the Pacific coast of Mexico in June 2013. The third named tropical cyclone of the 2013 Pacific hurricane season, the storm system formed from a tropical wave south of Manzanillo, Colima, on June 23. The cyclone intensified into a tropical storm on June 24, and soon after strengthened into a hurricane on June 25. Early the following day, Cosme attained its peak intensity as a Category 1 hurricane on the Saffir–Simpson scale with maximum sustained winds of 85 mph (140 km/h) and a minimum barometric pressure of 980 mbar. However, Cosme then began to encounter stable air and lower sea surface temperatures, causing the system to weaken to a tropical storm late on June 26. The system continued to weaken and degenerated into a remnant low pressure surface trough about 690 mi (1,110 km) west-southwest of Cabo San Lucas, Mexico, on June 27. The remnants persisted until dissipating well east-southeast of the Hawaiian Islands on July 1.
Hurricane Amanda was the strongest Eastern Pacific tropical cyclone ever recorded in the month of May. The first named storm, hurricane and major hurricane of the 2014 Pacific hurricane season, Amanda originated from a tropical wave that had entered the Eastern Pacific on May 16. Slow development occurred as it tracked westward, and development into a tropical depression occurred on May 22. The depression later strengthened into a tropical storm on May 23. Amid very favorable conditions, Amanda then rapidly intensified late on May 23, eventually reaching its peak intensity on May 25 as a high-end Category 4 hurricane. Afterwards, steady weakening occurred due to upwelling beneath the storm, and Amanda fell below major hurricane intensity on May 26. Rapid weakening occurred and the cyclone eventually dissipated on May 29.
Tropical Storm Boris was a weak and short-lived tropical cyclone that brought rainfall to the Isthmus of Tehuantepec and surrounding areas in June 2014. The second named storm of the season, Boris developed from the interaction of a low-level trough and a Kelvin wave south of Mexico late on June 2. Initially a tropical depression, the system moved generally northward and strengthened into Tropical Storm Boris by midday on June 3. About six hours later, Boris peaked with maximum sustained winds of 45 mph (75 km/h) – indicative of a weak tropical storm. By early on June 4, interaction with land caused the storm to weaken, deteriorating to a tropical depression. Later that day, Boris degenerated into an area of remnant low pressure, before fully dissipating over the Gulf of Tehuantepec on June 5.
Tropical Storm Trudy was a short-lived tropical cyclone in October 2014 that caused significant flooding in southern Mexico. The storm originated from an area of low pressure associated with a monsoon trough near Central America in early October. A slow-moving system, the low eventually consolidated into a tropical depression on October 17 near the Mexican coastline. Favorable environmental conditions aided rapid development of Trudy. Within 15 hours of its designation, an eye formed over the storm's center. Trudy ultimately achieved its peak as a strong tropical storm with 65 mph (100 km/h) winds as it made landfall just southeast of Marquelia, Mexico. The region's mountainous terrain quickly weakened Trudy and the cyclone dissipated early on October 19. Though the cyclone dissipated, its remnant energy later contributed to the formation of Tropical Storm Hanna in the Atlantic.
Hurricane Odile is tied for the most intense landfalling tropical cyclone in the Baja California Peninsula during the satellite era. Sweeping across the peninsula in September 2014, Odile inflicted widespread damage, particularly in the state of Baja California Sur, in addition to causing lesser impacts on the Mexican mainland and Southwestern United States. The precursor to Odile developed into a tropical depression south of Mexico on September 10 and quickly reached tropical storm strength. After meandering for several days, Odile began to track northwestward, intensifying to hurricane status before rapidly reaching its Category 4 hurricane peak intensity on September 14. The cyclone slightly weakened before making landfall near Cabo San Lucas with winds of 125 mph (205 km/h). Odile gradually weakened as it tracked across the length of the Baja California Peninsula, briefly crossing into the Gulf of California before degenerating into a remnant system on September 17. These remnants tracked northeastward across the Southwestern United States before they were no longer identifiable on September 19.
Hurricane Carlos was an unusually small tropical cyclone which affected the western coast of Mexico in June 2015. Forming as the third named storm and hurricane of the annual hurricane season, Carlos developed from a trough first noted by the National Hurricane Center on June 7. The disturbance gradually organized and was designated as a tropical depression three days later while south of the Mexican Pacific coast. Drifting slowly northwestward, the depression was upgraded further to a tropical storm. Although persistent wind shear and dry air hampered intensification early on, Carlos strengthened into a hurricane on June 13 after moving into a more favorable environment. However, the return of dry air and upwelling of cooler waters caused the system to deteriorate into a tropical storm. Paralleling the Mexican coast, Carlos later regained hurricane intensity on June 15 and attained peak winds of 90 mph (150 km/h) a day later. The reprieve was brief, however, as the onset of wind shear, land interaction, and dry air afterward led to rapid weakening. On June 17, Carlos degenerated into a remnant area of low pressure, having made landfall in Jalisco earlier that day. By the morning of June 18, Carlos was declared to have completely dissipated.
The 2018 Pacific hurricane season produced the highest accumulated cyclone energy (ACE) value on record. With 23 named storms, it was the fourth-most active season on record, tied with 1982. The season officially began on May 15 in the eastern Pacific, and on June 1 in the central Pacific; they both ended on November 30. These dates conventionally delimit the period of each year when most tropical cyclones form in the Pacific basin, as illustrated when the first tropical depression formed on May 10.
Hurricane Rosa was the first tropical cyclone to make landfall in the Mexican state of Baja California since Nora in 1997. The seventeenth named storm, tenth hurricane, and seventh major hurricane of the 2018 Pacific hurricane season, Rosa originated from a broad area of low pressure that the National Hurricane Center began monitoring on September 22. The disturbance moved westward and then west-northwestward for a few days, before developing into a tropical depression on September 25. Later that day, the depression strengthened into Tropical Storm Rosa. One day later, Rosa became a hurricane. On September 27, Rosa began a period of rapid intensification, ultimately peaking as a Category 4 hurricane with maximum sustained winds of 150 mph and a minimum central pressure of 936 mbar on the next day. Over the next couple of days, Rosa turned towards the northeast. By September 29, Rosa had weakened into a Category 2 hurricane due to ongoing structural changes and less favorable conditions. Later on the same day, Rosa re-intensified slightly. On September 30, Rosa resumed weakening as its core structure eroded. Early on October 1, Rosa weakened into a tropical storm. On October 2, Rosa weakened to a tropical depression and made landfall in Baja California. Later in the day, Rosa's remnants crossed into the Gulf of California, with its surface and mid-level remnants later separating entirely. The mid-level remnants of Rosa continued to travel north, reaching northeast Arizona late in the day. On October 3, Rosa's remnants were absorbed into an upper-level low situated off the coast of California.
Tropical Storm Vicente was a weak and small tropical cyclone affected the southwestern Mexico in late October 2018, causing deadly flooding and mudslides. The twenty-first named storm of the 2018 Pacific hurricane season, Vicente originated from a trough of low pressure that formed within a large area of disturbed weather near Central America early on October 19. Around midday, the disturbance organized into a tropical depression, which prompted the National Hurricane Center to begin issuing advisories. Later in day, the depression strengthened into a tropical storm and was assigned the name Vicente. Despite having only been a weak tropical storm, Vicente developed an intermittent eye-like feature. Unfavorable conditions prevented strengthening until late on October 20. At that time, Vicente peaked with maximum sustained winds of 50 mph and a minimum central pressure of 1002 mbar. A day later, Vicente began to weaken due increasing wind shear before slightly restrengthening early on October 22. On October 23, Vicente weakened into a tropical depression. Later in the day, Vicente degenerated into a remnant low after making landfall in southwestern Mexico, before dissipating soon afterward.
Tropical Storm Ileana was a tropical cyclone that affected Western Mexico, causing multiple deaths and flooding. The ninth named storm of the 2018 Pacific hurricane season, Ileana originated from a tropical wave that the National Hurricane Center began monitoring on July 26 as it left the west coast of Africa. The wave travelled across the Atlantic Ocean with no thunderstorm activity, before crossing into the Eastern Pacific Ocean on August 4. The disturbance quickly and unexpectedly organized into a tropical depression later in the day. Initially, the depression was well defined, but it soon degraded due to unfavorable conditions. It began to strengthen on August 5, becoming Tropical Storm Ileana. On August 6, Ileana peaked with winds of 65 mph (100 km/h) and a pressure of 998 mbar. Ileana began to develop an eyewall structure soon after, but became intertwined with nearby Hurricane John. John disrupted Ileana and ultimately absorbed it on August 7.
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