The 2020 Pacific hurricane season was a near average Pacific hurricane season in terms of named storms, featuring 17 (including one unnamed tropical storm which was operationally classified as a tropical depression), but well below average season for hurricanes and major hurricanes, with only 4 hurricanes and 3 major hurricanes forming. Additionally, no tropical cyclones formed in the Central Pacific basin for the first time since 2017. The season officially began on May15 in the East Pacific Ocean (east of 140°W), and on June1 in the Central Pacific (from 140°W to the International Date Line, north of the equator; they both ended on November30. These dates conventionally delimit the period of each year when most tropical cyclones form in the respective regions. However, the formation of tropical cyclones is possible at any time of the year, as illustrated in 2020 by the formation of the season's first system, Tropical Depression One-E, on April25. This was the earliest formation of a tropical cyclone on record in the eastern Pacific basin proper. The final system of the season was Tropical Storm Polo, which dissipated on November19.
The most significant storms of the season were Tropical Storm Amanda and Hurricane Genevieve. Amanda developed near Central America in late May and struck Guatemala, causing widespread damage in neighboring El Salvador and killing 40 people amid the COVID-19 pandemic in the latter country. Genevieve passed closely to the tip of the Baja California Peninsula in August, bringing hurricane-force winds and heavy rainfall, killing six and causing an estimated $50 million in damage. Otherwise, impact from other storms was minimal. In late July, Hurricane Douglas made an extremely close pass to Hawaii, with its weak southern eyewall crossing Oahu, causing minor effects. The remnant moisture of Tropical Storm Fausto brought dry thunderstorms and lightning to Northern California, sparking hundreds of fires that contributed to the state's worst fire season in recorded history, and the remnants of Genevieve dropped heavy rainfall in Arizona and Southern California. Tropical Storm Hernan moved very near the coast of southwestern Mexico, causing an additional fatality and several millions of dollars worth of damage. Collectively, the tropical cyclones of this season caused about US$267.91 million in damage and 47 deaths.
On May20, 2020, the Servicio Meteorológico Nacional (SMN) issued its forecast for the season, predicting a total of 15–18 named storms, 8–10 hurricanes, and 4–5 major hurricanes to develop.[3] The next day, the National Oceanic and Atmospheric Administration (NOAA) issued their outlook, calling for a below-normal to near-normal season with 11–18 named storms, 5–10 hurricanes, 1–5 major hurricanes, and an accumulated cyclone energy index of 60% to 135% of the median. Factors they expected to reduce activity were near- or below-average sea surface temperatures across the eastern Pacific and the El Niño–Southern Oscillation remaining in the neutral phase, with the possibility of a La Niña developing.[4]
Tropical Storms Iselle (left) and Hernan (center) on August 26, with Hurricane Laura in the North Atlantic basin in the top right
Although the hurricane season in the eastern Pacific did not officially begin until May15, and on June1 in the central Pacific,[5] activity this year began several weeks prior with the formation of Tropical Depression One-E on April25. This marked the earliest formation of a tropical cyclone on record in the eastern Pacific basin, surpassing 2017's Tropical Storm Adrian.[6] Among relatively unfavorable conditions, the depression soon dissipated without developing further,[7] and activity would not resume in the basin until nearly a month later with the formation of Tropical Depression Two-E near the coast of Guatemala on May 30. This system would later become Tropical Storm Amanda, the first named storm of the season and one of the worst natural disasters in El Salvador in around two decades.[8][9] Not for nearly another month after Amanda, Tropical Depression Three-E would briefly become Tropical Storm Boris on June 25 well out to sea before weakening in the Central Pacific basin.[10][11] A short-lived tropical depression would form near Baja California Sur just 2 days after Boris's dissipation and quickly weaken.[12] Moving into July, Tropical Storm Cristina formed on July 6 and slowly intensified to a peak intensity of 70 miles per hour (110km/h), barely missing hurricane status.[13][14] Activity continued as yet another tropical depression, Six-E, formed on July 13 but quickly dissipated among the unfavorable conditions unfolding in the basin.[15] Two more tropical systems formed in mid July, Tropical Depression Seven-E and Tropical Storm Douglas. Seven-E was short lived and although it did gain tropical storm intensity, it was operationally left unnamed. Douglas strengthened into the first hurricane of the season at 15:00UTC on July 22, marking the fourth–latest date any season had gone without a hurricane. Douglas would later strengthen into a Category 4 hurricane and brush Hawaii with rain and gusty winds.[16]
A burst of activity occurred in early August, with a tropical wave south of Mexico evolving into Tropical Storm Elida on August 9, later to become the second hurricane of the season. Elida was generally short lived, but with the formation of Tropical Depression Ten-E, Tropical Storm Fausto, and Hurricane Genevieve activity continued. Genevieve later became the second major hurricane of the season before briefly effecting Baja California Sur as a minimal hurricane. Two additional tropical cyclones, Tropical Storms Hernan and Iselle, formed in late August. Both were generally weak and did not make landfall, although the former brought heavy flooding and mudslides to western Mexico. Later, on September 5, the remnants of former Atlantic tropical cyclone Nana reformed into a new cyclone in the Pacific named Julio. After Julio, Karina and Lowell formed. Near the end of September, Hurricane Marie formed and rapidly intensified up to Category 4 strength before weakening out to sea, becoming the strongest storm of the season. The only October storm of the season, Norbert, lasted for 10 days. After almost a month of inactivity, Odalys formed on November 3, and dissipated three days later without affecting land. Tropical Storm Polo formed close to the end of the season, but it was also short-lived and weak.
The Accumulated Cyclone Energy (ACE) index for the 2020 Pacific hurricane season (Eastern Pacific and Central Pacific combined) as calculated by Colorado State University using data from the National Hurricane Center was 77.3units.[nb 1][18] Broadly speaking, ACE is a measure of the power of a tropical or subtropical storm multiplied by the length of time it existed. It is only calculated for full advisories on specific tropical and subtropical systems reaching or exceeding wind speeds of 39 miles per hour (63km/h).
A disturbance developed within the Intertropical Convergence Zone (ITCZ) on April17, aided by the passage of a convectively-coupled kelvin wave (CCKW) – an eastward-propagating area of enhanced thunderstorm activity near the equator. The disturbance moved westward within the ITCZ over the next several days, and after developing a well-defined center and organized convection, it was designated as Tropical Depression One-E at 06:00UTC on April25 about 805mi (1,295km) southwest of Baja California Sur. Moving northwestward, the depression retained organized deep convection until shortly after 00:00UTC the next day. Dry air and westerly wind shear caused the depression to weaken and degenerate to a remnant low by 12:00UTC. The remnant low turned west and opened up into a trough at 18:00UTC on April27.[19]
The combination of an upper level low over northeastern Mexico and a passing CCKW over the East Pacific caused an area of low pressure to form south of Guatemala and El Salvador on May27. Two days later, the system interacted with a tropical wave that first originated from Africa on May18. The conglomeration of these features led to the formation of a tropical depression around 18:00UTC on May30; it was positioned about 115mi (185km) south of Puerto San José, Escuintla. Moving northeastward around the periphery of a large cyclonic gyre over northern Central America, the compact depression continued to organize, strengthening into Tropical Storm Amanda at 06:00UTC the next day. About four hours later, Amanda made landfall at peak intensity near Las Lisas, Santa Rosa. Amanda rapidly degenerated as it moved inland, with its center dissipating around 18:00UTC. The remnants of the system moved northward into the Bay of Campeche and redeveloped into the Atlantic's Tropical Storm Cristobal.[20]
In El Salvador, torrential rainfall caused significant damage along coastal cities in the country as rivers overflowed and swept away buildings.[21] Amanda killed 14 people in El Salvador,[22] of which at least six died due to flash flooding, and one died from a collapsed home.[23] More than 900 homes were damaged across the country and 1,200 families were evacuated to 51 shelters across La Libertad, San Salvador, Sonsonate, and San Vicente. In the capital, San Salvador, 50 houses were destroyed and 23 vehicles fell into a sinkhole.[24][25] El Salvador President Nayib Bukele declared a 15-day national state of emergency due to the storm.[23] Movement restrictions in place for the ongoing COVID-19 pandemic were temporarily lifted to allow people to purchase medicines, while hardware stores were allowed to open with limited capacity so people could purchase equipment for repairs.[24]
The interaction between a tropical wave, a preexisting area of disturbed weather, and the favorable phase of the Madden-Julian Oscillation (MJO) led to the formation of a surface low late on June23. Deep convection coalesced with this circulation over the ensuing hours, and a tropical depression developed around 06:00UTC on June24. The system struggled via the effects of nearby dry air and some wind shear as it moved west to west-northwest under the subtropical ridge. Nonetheless, it intensified into Tropical Storm Boris around 18:00UTC on June25 when deep convection was most prevalent. A further increase in upper-level winds prevented Boris from strengthening beyond minimal tropical storm intensity, and it instead weakened to a tropical depression again twelve hours later before crossing into the Central Pacific basin. All associated thunderstorm activity dissipated by June28, and Boris degenerated to a remnant area of low pressure by 00:00UTC that day. The post-tropical cyclone curved west-southwest and dissipated well south-southeast of the Hawaiian Islands on June30.[26]
A broad area of disturbed weather, at least partially enhanced by a tropical wave, formed near the Gulf of Tehuantepec on June25. The system paralleled the Mexican coastline and only slowly organized over the coming days, eventually meeting the criteria to be designated a tropical depression around 18:00UTC on June29. Despite coalescing deeper convection near the center at the time of formation, Tropical Depression Four-E failed to attain winds greater than 30mph (45km/h) as it encountered hostile southwesterly wind shear and colder ocean waters. Instead, the system degenerated to a remnant area of low pressure by 18:00UTC on June30. The low turned north and dissipated well south of Baja California on July1.[27]
A tropical wave emerged off the west coast of Africa on June20 and crossed into the East Pacific on July3, where it interacted with the monsoon trough and began to organize. This system developed a defined surface low on July6 and was classified as a tropical depression about 435mi (705km) south of Acapulco, Guerrero. Steered along a northwest trajectory by a mid-level ridge, the depression traversed a region of favorable conditions which enabled slow intensification.[28] Initial predictions from the NHC suggested significant strengthening of the cyclone.[29] However, Cristina instead encountered cooler waters and eventually drier air; it reached its peak intensity late on July10 with winds of 70mph (110km/h) as it passed west of Socorro Island. Thereafter, the cyclone turned west along the south side of the subtropical ridge and steady weakened. The storm degraded into a remnant low around 18:00UTC on July12 and degenerated into a trough on July15 about halfway between Hawaii and Baja California Sur.[28]
A tropical wave, emerging off Africa on July2, fractured over the western Atlantic several days later. The southern wave axis continued into the eastern Pacific, where its interaction with the monsoon trough resulted in the formation of an area of low pressure. This low failed to organize for a few days as it was hindered by strong northeasterly wind shear, and indeed it briefly opened up into a trough. On July13, a burst of extremely deep convection led to the redevelopment of a new circulation, and the system organized into a tropical depression around 12:00UTC that day. As the cyclone moved west-northwest away from Mexico, its associated convection waned, preventing the system from intensifying to a tropical storm. Instead, Tropical Depression Six-E dissipated into an open trough once again around 18:00UTC on July14.[30]
A tropical wave left Africa on July6 and emerged into the East Pacific on July13. It moved west and steadily coalesced despite an environment of cool ocean waters and dry air. At 00:00UTC on July20, the disturbance organized into a tropical depression. In real time, the depression was not assessed to have intensified further. However, a post-season review of satellite wind data revealed that it briefly became a 40mph (65km/h) tropical storm around the time it displayed a well-defined rainband in its western quadrant. This peak in intensity was short-lived as the system became devoid of deep convection; by 06:00UTC on July21, The system degenerated to a remnant low. The low then spun down and dissipated by 00:00UTC on July22.[31]
Douglas originated from a tropical wave that departed Africa on July8. It reached the East Pacific on July15, where environmental conditions fostered its development into a tropical depression at 00:00UTC on July20 about 805mi (1,295km) southwest of Baja California Sur. It strengthened into Tropical Storm Douglas eighteen hours later, and though it suffered a brief dry air intrusion, the storm further organized into a hurricane by 18:00UTC on July22. A period of rapid intensification was underway at this point, and over a 30-hour period, its winds increased to 130mph (215km/h) on July24. Shortly thereafter, the hurricane crossed into the Central Pacific on a course toward Hawaii. Cooler ocean waters led to gradual weakening of the hurricane as it approached the state. On July27, the center of Douglas passed just 60mi (95km) north of Oahu;[32] despite its proximity, effects were negligible.[33] Increasing wind shear caused the hurricane to rapidly unfold on July28, resulting in its degradation to a remnant low at 12:00UTC the next day well to the southeast of Midway Atoll. The low opened up into a trough just west of the International Date Line on July30.[32]
A tropical wave emerged off Africa on July26 and split over the Caribbean several days later, with the southern portion of the wave continuing into the eastern Pacific. A small low developed in association with this wave, eventually organizing into a tropical depression by 18:00UTC on August8. Twelve hours later, the depression intensified into Tropical Storm Elida while paralleling the coastline of Mexico. Owing to favorable environmental conditions, Elida intensified steadily on August9 and then rapidly the following day, attaining hurricane strength around 18:00UTC on August10. An eye developed within the storm's compact and symmetrical central dense overcast, and Elida reached peak winds of 105mph (165km/h) by 12:00UTC the next morning. Ultimately, the influence of dry air and cooler waters caused the storm to swiftly weaken, and it degenerated to a remnant area of low pressure by 00:00UTC on August13 while positioned west of Baja California Sur. The low turned north before opening up into a trough a little over 24hours later.[34]
An area of disturbed weather formed within the monsoon trough southwest of Baja California on August11. It moved west and gradually organized, becoming a tropical depression at 06:00UTC on August13 while located over the open East Pacific. The system tracked over warm ocean waters, but it was persistently hindered by strong northeasterly wind shear. Thus, it maintained peak winds of 35mph (55km/h) and failed to ever become a tropical storm. The depression moved erratically as ridging to its north weakened. After a few days of producing intermittent convection, the system degenerated to a remnant low around 12:00UTC on August16. It opened up into a trough the next day.[35]
A tropical wave entered the East Pacific on August9 and spawned the development of a tropical depression around 00:00UTC on August16, despite ongoing easterly wind shear. The depression intensified into Tropical Storm Fausto six hours later, but it was immediately stripped of its convection and thus fell back to a tropical depression only six hours after earning a name. Fausto curved toward the west and moved over colder waters, which further enabled its weakening. The system degenerated to a remnant low around 12:00UTC on August17, far away from land. The low moved west and opened up into a trough about a day later.[36]
A large plume of moisture brought northwards by Fausto generated massive thunderstorms across a large portion of Northern California, beginning on August 16.[37] These storms produced mostly dry lightning with little to no rain, with almost 11,000 lightning strikes occurring in the state between August 16 and 17. The lightning from these storms sparked 367[38]fires across the state, several of which became very large in a short period of time, threatening thousands of structures and forcing thousands of people to evacuate.[39] The massive SCU Lightning Complex, August Complex, CZU Lightning Complex, and North Complex fires were connected to the thunderstorms associated with Fausto.[40]
A tropical wave crossed Central America on August13, becoming the season's next tropical depression around 12:00UTC on August16 while located about 300mi (485km) south of Puerto Ángel, Oaxaca. Favorable environmental conditions supported its rapid development while it moved northwest parallel to Mexico. It intensified into Tropical Storm Genevieve at 18:00UTC on August16 and became a hurricane around 12:00UTC the next morning. Within the ensuing 24-hour period, Genevieve's maximum winds increased from 75mph (120km/h) to 130mph (215km/h), equivalent to a Category4 hurricane, as it harbored a well-defined eye on satellite imagery. A weakening trend began almost immediately as the storm faced higher southwesterly wind shear and a track over colder waters left by Tropical Storm Elida. The system curved north for a time, nearly moving onshore Baja California Sur before it bent back northwest. This track over colder waters caused Genevieve to lose convection and degenerate to a remnant low around 18:00UTC on August21. It dissipated a little under a day later.[41]
Genevieve's close pass to Baja California Sur brought its strong winds onshore, with a peak sustained wind of 70mph (110km/h) and gust of 90mph (140km/h) observed at Cabo San Lucas Marina. Isolated rainfall totals around 4in (100mm) overspread Oaxaca and Guerrero, and a storm-peak accumulation of 11.2in (280mm) occurred at Cabo San Lucas. Resultant flooding caused some damage to hydraulic, highway, and electrical systems throughout Baja California Sur; total damage topped $50million. Six people were killed: two via landslides and two via swollen rivers in Oaxaca, plus two from drownings at the resort of Los Cabos in Baja California Sur.[41]
The favorable phase of the MJO moved across the East Pacific, enhancing the monsoon trough and spawning an area of disturbed weather. Three areas of low pressure formed along this trough, with the first one developing into Tropical Storm Hernan around 06:00UTC on August26. Broad in nature and under the influence of easterly wind shear, Hernan attained peak winds of 45mph (75km/h) on August27 but began to rapidly weaken the next day as it moved north just offshore the Mexico coastline. It degenerated to a remnant low at 18:00UTC on August28. The low curved west around a broad circulation that contained the developing Tropical Storm Iselle before being absorbed by that feature later in the day.[42]
In Mexico, 97,000 customers lost electricity.[43] Hernan dropped heavy rainfall across southwestern Mexico, peaking at 23.24in (590mm) in Jalisco.[44] causing flash flooding and mudslides in several states.[45] At least 400 people were evacuated in Jalisco,[46] and 18 people stuck on their roof in the state had to be rescued.[47] In Cihuatlán, roughly 365 residents evacuated into shelters.[48] A sinkhole shut down a portion of Mexican Federal Highway 80 between Santa Cruz and San Patricio, a mudslide closed down another part of the freeway near Lázaro Cárdenas. The Cuixmala River overflowed its banks, causing parts of Mexican Federal Highway 200 to shut down. The town of La Manzanilla was mostly inundated by floodwaters which caused a bridge near the town to collapse.[49] Several schools were damaged by Hernan in the state of Colima.[50] In Tamala, a parota tree fell on a road, blocking traffic.[51] In Manzanillo, some homes and streets were damaged and covered with mud.[52] In Nayarit, a mudslide occurred on a hill behind a populated neighborhood in Xalisco, however, no damage has been reported from this incident.[53] Despite Hernan weakening into a tropical depression before landfall in Baja California Sur, local weather services in the area advised residents to take extreme precautions.[54] Total damage from Hernan in Mexico was estimated at MXN$594.05million pesos (US$26.91million) by a federal Damage Assessment Committee.[55]
Within the broad cyclonic circulation across Central America and adjacent waters, a westward-moving tropical wave spawned an area of low pressure on August23. This low, originally weak and ill-defined, was enhanced by a CCKW two days later. Following increased organization, it became a tropical depression around 12:00UTC on August26 while positioned well southwest of Baja California Sur. The depression strengthened into Tropical Storm Iselle six hours later. The newly formed system encountered strong east-northeasterly wind shear, but the effects of this shear were offset by strong diffluence that aided in deep convection. Iselle reached peak winds of 60mph (95km/h) early on August28 when it displayed semblance of a mid-level eye on microwave imagery. As the cyclone moved north-northeast, though, it encountered a more hostile environment and began to weaken. The system degenerated to a remnant low at 18:00UTC on August30, and that low dissipated 24hours later just offshore Baja California Sur.[56]
On September3, the Atlantic's Hurricane Nana made landfall in southern Belize. It crossed Mexico over the next day, with its low-level center dissipating but its mid-level remnants continuing into the East Pacific. Plentiful convection spawned a new circulation and yielded tropical storm-force winds, resulting in the designation of Tropical Storm Julio about 85mi (140km) southwest of Puerto Angel, Oaxaca, at 00:00UTC on September5. The new storm moved unusually quick toward the west-northwest and reached peak winds of 45mph (75km/h) on September6 when a concentrated burst of thunderstorms developed over its center. An uptick in easterly wind shear prevented additional development, and Julio instead opened up into a trough around 06:00UTC on September7. The next day, its remnants were absorbed by a broad area of low pressure southwest of Socorro Island.[57]
A tropical wave departed Africa on August26 and emerged into the East Pacific by September7, where it only slowly developed. By 18:00UTC on September12, a new tropical depression formed about 540mi (870km) south-southwest of Baja California Sur. The system moved west-northwest on the southwest side of a ridge throughout its duration. In the wake of its formation, the depression struggled with northeasterly wind shear which kept the center exposed. Despite this, it intensified into Tropical Storm Karina around 06:00UTC on September13. Shear decreased the following day, allowing Karina to attain peak winds of 60mph (95km/h) on September15. Ocean waters eventually began to decrease, causing a weakening trend that resulted in Karina's degeneration to a remnant low at 18:00UTC on September16. The low turned west and opened up into a trough early on September18.[58]
A trough developed south of the Atlantic's Tropical Storm Beta on September28, stretching from the southwestern Gulf of Mexico into the East Pacific. A disturbance formed on the southern end of this trough, eventually organizing into a tropical depression at 18:00UTC on September20. It was located about 575mi (925km) south-southeast of Baja California Sur then. Hostile wind shear initially prevented the depression from intensifying, but it lessened somewhat on September21, allowing the system to become Tropical Storm Lowell around 18:00UTC that day. Lowell attained peak winds of 50mph (85km/h) on September23, but it began to weaken later that day while encountering stronger wind shear and cooler ocean waters. Deep convection was gradually stripped from the cyclone's center, and Lowell degenerated to a remnant low at 18:00UTC on September25. The low moved west and opened up into a trough on September28 well east of the Big Island.[59]
A tropical wave interacted with the monsoon trough south of Mexico and an overarching CCKW, resulting in a broad disturbance on September24. The system moved west-northwest, coalescing into a tropical depression around 06:00UTC on September29 while located about 415mi (670km) southwest of Manzanillo. Twelve hours later, it became Tropical Storm Marie. The nascent storm moved through an environment of warm ocean waters, abundant moisture, and decreasing northeasterly wind shear which facilitated its rapid organization. Marie became a hurricane at 00:00UTC on October1; within 30hours, it reached its peak as a Category4 hurricane with winds of 140mph (220km/h). Marie displayed a well-defined eye surrounded by cloud tops as cool as −105°F (−75°C) around this time. Inner core processes modulated Marie's strength for a time, but it eventually crossed into cooler waters, drier air, and higher southwesterly wind shear. These factors caused it to degenerate to a remnant low by 18:00UTC on October6. A brief burst of convection nudged the low northward on October7, but the cyclone curved west-southwest and opened up into a trough three days later, just after crossing into the Central Pacific.[60]
A tropical wave left Africa on September19 and moved over Central America on September29. It gradually became more concentrated south of Mexico, developing into a tropical depression about 635mi (1,020km) southwest of Acapulco at 06:00UTC on October5. The system moved northwest and it intensified amid favorable environmental conditions. Spiral banding increased near the center, signaling its intensification to Tropical Storm Norbert twelve hours after formation. Norbert attained peak winds of 60mph (95km/h) on October6, but it encountered drier air and increasing westerly wind shear. Convection burst intermittently over subsequent days, but the cyclone weakened as it underwent a cyclonic loop. Around 00:00UTC on October10, the system opened up into a trough south of Manzanillo.[61]
The remnants of Norbert moved generally northwest and continued to face unfavorable wind shear. However, sporadic bursts of convection led to a new mid-level center and eventually a surface one as well. These features aligned, and thunderstorm activity increased, leading to Norbert's redesignation as a tropical depression near 18:00UTC on October13. It regained tropical storm status and reached a secondary peak of 45mph (75km/h) on October14. Just as its previous stint as a tropical cyclone, though, the cyclone encountered hostile conditions and began to weaken. It degenerated to a remnant low near 00:00UTC on October15 and dissipated less than 12hours later to the west of Baja California Sur.[61]
A tropical wave passed over Central America and entered the Eastern Pacific basin on October29. Its associated thunderstorm activity remained relatively disorganized until November1, when a broad area of low pressure developed within the system. By 18:00UTC on November3, the NHC determined the system was sufficiently organized to be designated Tropical Storm Odalys while it was centered about 730mi (1,175km) southwest of Baja California Sur. Odalys intensified somewhat over the next few days while moving west-northwest despite strong wind shear and dry air impinging on the system. At 00:00UTC on November5, the system reached its peak intensity with winds of 50mph (85km/h). Wind shear increased further shortly afterwards, causing Odalys to weaken quickly and eventually become a post-tropical cyclone at 18:00UTC on November5. Its shallow remnants turned southwest under the influence of a strong high-pressure area and dissipated by November8.[62]
The season's final storm developed from an area of convection within the monsoon trough that may have been enhanced by a Gulf of Tehuantepec gap wind event over preceding days. On November14, a broad area of low pressure formed. Both the low and associated thunderstorm activity gained cohesion over the coming days, resulting in the formation of a tropical depression around 18:00UTC on November17 to the southwest of Baja California Sur. The depression intensified into Tropical Storm Polo six hours later and reached peak winds of 45mph (75km/h) the following morning. As the system moved west-northwest, it encountered an increasingly hostile environment, and Polo weakened to a tropical depression early on November19. By 18:00UTC that day, the cyclone degenerated to a remnant area of low pressure that moved west and then west-southwest prior to dissipating into an open trough on November21.[63]
The following list of names was used for named storms that formed in the North Pacific Ocean east of 140°W during 2020.[64] This is the same list used for the 2014 season, with the exception of the name Odalys, which replaced Odile. The name Odalys was used for the first time this year. No names were retired following the season, so this list will be used again for the 2026 season.[65]
For storms that form in the North Pacific from 140°W to the International Date Line, the names come from a series of four rotating lists. Names are used one after the other without regard to year, and when the bottom of one list is reached, the next named storm receives the name at the top of the next list.[65] No storms formed within the area in 2020. Named storms in the table above that crossed into the area during the season are noted (*).[66]
Season effects
This is a table of all of the storms that formed in the 2020 Pacific hurricane season. It includes their name, duration (within the basin), peak classification and intensities, areas affected, damage, and death totals. Deaths in parentheses are additional and indirect (an example of an indirect death would be a traffic accident), but were still related to that storm. Damage and deaths include totals while the storm was extratropical, a wave, or a low, and all of the damage figures are in 2020 USD.
↑ The total represents the sum of the squares of the maximum sustained wind speed (knots) for every (sub)tropical storm's intensity of over 33knots (38mph, 61km/h), divided by 10,000 while they are above that threshold; therefore, tropical depressions are not included.
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The 2013 Pacific hurricane season was an above average Pacific hurricane season with 21 tropical cyclones forming. Of these, 20 became named storms – 18 in the Eastern Pacific basin, and 2 in the Central Pacific basin. Of the 18 named storms in the east, 9 became hurricanes, with one, Raymond, becoming the season's only major hurricane. In the central, neither named storm became a hurricane. It was also a below-normal season in terms of Accumulated cyclone energy (ACE), as many of its systems were weak and short-lived. The season officially began on May 15 in the Eastern Pacific and started on June 1 in the Central Pacific; both ended on November 30. These dates conventionally delimit the period of each year when most tropical development occurs in these North Pacific basins. The first cyclone, Tropical Storm Alvin, formed on May 15, and the last, Tropical Storm Sonia, dissipated on November 4. It was below average only Category 3 storm was since 1981.
The 2014 Pacific hurricane season was one of the busiest and costliest Pacific hurricane seasons since the keeping of reliable records began in 1949. 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 these regions of the Pacific.
The 2015 Pacific hurricane season is the second-most active Pacific hurricane season on record, with 26 named storms, only behind the 1992 season. A record-tying 16 of those storms became hurricanes, and a record 11 storms further intensified into major hurricanes throughout the season. The Central Pacific, the portion of the Northeast Pacific Ocean between the International Date Line and the 140th meridian west, had its most active year on record, with 16 tropical cyclones forming in or entering the basin. Moreover, the season was the third-most active season in terms of accumulated cyclone energy, amassing a total of 290 units. The season officially started 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 Northeast Pacific basin. However, the formation of tropical cyclones is possible at any time of the year. This was shown when a tropical depression formed on December 31. The above-average activity during the season was attributed in part to the very strong 2014–2016 El Niño event.
The 2016 Pacific hurricane season was tied as the fifth-most active Pacific hurricane season on record, alongside the 2014 season. Throughout the course of the year, a total of 22 named storms, 13 hurricanes and six major hurricanes were observed within the basin. Although the season was very active, it was considerably less active than the previous season, with large gaps of inactivity at the beginning and towards the end of the season. It officially started 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 these regions of the Pacific Ocean. However, tropical development is possible at any time of the year, as demonstrated by the formation of Hurricane Pali on January 7, the earliest Central Pacific tropical cyclone on record. After Pali, however, no tropical cyclones developed in either region until a short-lived depression on June 6. Also, there were no additional named storms until July 2, when Tropical Storm Agatha formed, becoming the latest first-named Eastern Pacific tropical storm since Tropical Storm Ava in 1969.
The 2017 Pacific hurricane season was an above average Pacific hurricane season in terms of named storms, though less active than the previous three, featuring eighteen named storms, nine hurricanes, and four major hurricanes. Despite the considerable amount of activity, most of the storms were weak and short-lived. The season officially started on May 15 in the eastern 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 respective regions. However, the formation of tropical cyclones is possible at any time of the year, as illustrated in 2017 by the formation of the season's first named storm, Tropical Storm Adrian, on May 9. At the time, this was the earliest formation of a tropical storm on record in the eastern Pacific basin proper. The season saw near-average activity in terms of accumulated cyclone energy (ACE), in stark contrast to the extremely active seasons in 2014, 2015, and 2016; and for the first time since 2012, no tropical cyclones formed in the Central Pacific basin. However, for the third year in a row, the season featured above-average activity in July, with the ACE value being the fifth highest for the month. Damage across the basin reached $375.28 million (2017 USD), while 45 people were killed by the various storms.
The 2010 Pacific hurricane season was one of the least active seasons on record, featuring the fewest named storms since 1977. The season officially started on May 15 in the eastern Pacific—east of 140°W—and on June 1 in the central Pacific—between the International Date Line and 140°W—and lasted until November 30. These dates typically cover the period of each year when most tropical cyclones form in the eastern Pacific basin. The season's first storm, Tropical Storm Agatha, developed on May 29; the season's final storm, Tropical Storm Omeka, degenerated on December 21.
The 2012 Pacific hurricane season was an above-average year in which seventeen named storms formed. The hurricane season officially began on May 15 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 regions. These dates conventionally delimit the period during each year when most tropical cyclones form in the northeastern Pacific Ocean. This year, the first storm of the season, Tropical Storm Aletta, formed on May 14, and the last, Tropical Storm Rosa, dissipated on November 3.
The 2013 Pacific hurricane season was an above-average year in which twenty named storms developed. The hurricane season officially began on May 15 in the East Pacific, coinciding with the formation of Tropical Storm Alvin, and on June 1 in the Central Pacific; it ended on November 30 in both basins. These dates conventionally delimit the period during each year when most tropical cyclones form. The final system of the year, Tropical Storm Sonia, dissipated on November 4.
The 2018 Pacific hurricane season was one of the most active Pacific hurricane seasons on record, producing the highest accumulated cyclone energy value on record in the basin. The season had the fourth-highest number of named storms – 23, tied with 1982. The season also featured eight landfalls, six of which occurred in Mexico. 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. However, tropical cyclone formation is possible at any time of the year, as illustrated when the first tropical depression formed on May 10, five days prior to the official start of the season.
The 2019 Pacific hurricane season was an above average season which produced nineteen named storms, most of which were rather weak and short-lived. Only seven hurricanes formed, the fewest since 2010. The season officially began 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. This season was one of the latest-starting Pacific hurricane seasons on record, with the first tropical cyclone, Hurricane Alvin, forming on June 25. The final system, Tropical Depression Twenty-One-E, dissipated on November 18.
The 2021 Atlantic hurricane season was the third-most active Atlantic hurricane season on record in terms of number of tropical cyclones, although many of them were weak and short-lived. With 21 named storms forming, it became the second season in a row and third overall in which the designated 21-name list of storm names was exhausted. Seven of those storms strengthened into a hurricane, four of which reached major hurricane intensity, which is slightly above-average. The season officially began on June 1 and ended on November 30. These dates historically describe the period in each year when most Atlantic tropical cyclones form. However, subtropical or tropical cyclogenesis is possible at any time of the year, as demonstrated by the development of Tropical Storm Ana on May 22, making this the seventh consecutive year in which a storm developed outside of the official season.
The 2021 Pacific hurricane season was a moderately active Pacific hurricane season, with above-average activity in terms of number of named storms, but below-average activity in terms of major hurricanes, as 19 named storms, 8 hurricanes, and 2 major hurricanes formed in all. It also had a near-normal accumulated cyclone energy (ACE). The season officially began on May 15, 2021 in the Eastern Pacific Ocean, and on June 1, 2021, in the Central Pacific in the Northern Hemisphere. The season ended in both regions on November 30, 2021. These dates historically describe the period each year when most tropical cyclogenesis occurs in these regions of the Pacific and are adopted by convention. However, the formation of tropical cyclones is possible at any time of the year, as illustrated by the formation of Tropical Storm Andres on May 9, which was the earliest forming tropical storm on record in the Eastern Pacific. Conversely, 2021 was the second consecutive season in which no tropical cyclones formed in the Central Pacific.
The 2022 Pacific hurricane season was a slightly above average hurricane season in the eastern North Pacific basin, with nineteen named storms, ten hurricanes, and four major hurricanes. Two of the storms crossed into the basin from the Atlantic. In the central North Pacific basin, no tropical cyclones formed. The season officially began on May 15 in the eastern Pacific, and on June 1 in the central; both ended on November 30. These dates historically describe the period each year when most tropical cyclogenesis occurs in these regions of the Pacific and are adopted by convention.
The 2020 Pacific hurricane season was an event in the annual cycle of tropical cyclone formation, in which tropical cyclones form in the Eastern Pacific Ocean. The season officially started on May 15 in the Eastern Pacific—east of 140°W—and began on June 1 in the Central Pacific—the region between the International Date Line and 140°W–and ended on November 30. These dates typically cover the period of each year when most tropical cyclones form in the Eastern Pacific basin according to the National Hurricane Center. However, tropical cyclones sometimes form outside the bounds of an official season, as was evidenced by the formation of Tropical Depression One-E on April 25. The season effectively ended with the dissipation of its final storm, Tropical Storm Polo, on November 19.
The 2023 Pacific hurricane season was an active and destructive Pacific hurricane season. In the Eastern Pacific basin, 17 named storms formed; 10 of those became hurricanes, of which 8 strengthened into major hurricanes – double the seasonal average. In the Central Pacific basin, no tropical cyclones formed for the fourth consecutive season, though four entered into the basin from the east. Collectively, the season had an above-normal accumulated cyclone energy (ACE) value of approximately 168 units. This season saw the return of El Niño and its associated warmer sea surface temperatures in the basin, which fueled the rapid intensification of several powerful storms. It officially began on May 15, 2023 in the Eastern Pacific, and on June 1 in the Central; both ended on November 30. These dates, adopted by convention, historically describe the period in each year when most tropical cyclogenesis occurs in these regions of the Pacific.
↑ "[California Event Report: Wildfire]". National Centers for Environmental Information. National Weather Service Forecast Office in Sacramento, California. 2020. Retrieved January 12, 2021.
↑ National Hurricane Operations Plan(PDF) (Report). Washington, D.C.: NOAA Office of the Federal Coordinator for Meteorological Services and Supporting Research. May 2020. p.3-9. Retrieved January 27, 2024.
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