2020 Pacific hurricane season
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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 File:2017 Events Collage V2.png, From top left, clockwise: The War Against ISIS at the Battle of Mosul (2016-2017); aftermath of the Manchester Arena bombing; The Solar eclipse of August 21, 2017 ("Great American Eclipse"); North Korea tests a ser ...
. The season officially began on May 15 in the East Pacific Ocean (east of 140°W), and on June 1 in the Central Pacific (from 140°W to the
International Date Line The International Date Line (IDL) is an internationally accepted demarcation on the surface of Earth, running between the South and North Poles and serving as the boundary between one calendar day and the next. It passes through the Pacific O ...
, north of the
equator The equator is a circle of latitude, about in circumference, that divides Earth into the Northern and Southern hemispheres. It is an imaginary line located at 0 degrees latitude, halfway between the North and South poles. The term can als ...
; 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 2020 by the formation of the season's first system, Tropical Depression One-E, on April 25. 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 November 19. The most significant storms of the season were Tropical Storm Amanda and Hurricane Genevieve. Amanda developed near
Central America Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...
in late May and struck
Guatemala Guatemala ( ; ), officially the Republic of Guatemala ( es, República de Guatemala, links=no), is a country in Central America. It is bordered to the north and west by Mexico; to the northeast by Belize and the Caribbean; to the east by H ...
, causing widespread damage in neighboring
El Salvador El Salvador (; , meaning " The Saviour"), officially the Republic of El Salvador ( es, República de El Salvador), is a country in Central America. It is bordered on the northeast by Honduras, on the northwest by Guatemala, and on the south b ...
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 The name Douglas has been used for seven tropical cyclones in the Eastern Pacific Ocean. * Hurricane Douglas (1984) – strongest hurricane of the season, never threatened land * Tropical Storm Douglas (1990) – killed one person in Mexico, where i ...
made an extremely close pass to
Hawaii Hawaii ( ; haw, Hawaii or ) is a state in the Western United States, located in the Pacific Ocean about from the U.S. mainland. It is the only U.S. state outside North America, the only state that is an archipelago, and the only stat ...
, with its weak southern eyewall crossing
Oahu Oahu () (Hawaiian language, Hawaiian: ''Oʻahu'' ()), also known as "The Gathering place#Island of Oʻahu as The Gathering Place, Gathering Place", is the third-largest of the Hawaiian Islands. It is home to roughly one million people—over t ...
, 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 Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...
and
Southern California Southern California (commonly shortened to SoCal) is a geographic and Cultural area, cultural region that generally comprises the southern portion of the U.S. state of California. It includes the Los Angeles metropolitan area, the second most po ...
. 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. __TOC__


Seasonal forecasts

On May 20, 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. The next day, the
National Oceanic and Atmospheric Administration The National Oceanic and Atmospheric Administration (abbreviated as NOAA ) is an United States scientific and regulatory agency within the United States Department of Commerce that forecasts weather, monitors oceanic and atmospheric conditio ...
(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 Accumulated cyclone energy (ACE) is a metric used by various agencies to express the energy released by a tropical cyclone during its lifetime. It is calculating by summing the square of a tropical cyclone's maximum sustained winds, measured ever ...
index of 60% to 135% of the median. Factors they expected to reduce activity were near- or below-average
sea surface temperature Sea surface temperature (SST), or ocean surface temperature, is the ocean temperature close to the surface. The exact meaning of ''surface'' varies according to the measurement method used, but it is between and below the sea surface. Air mass ...
s across the eastern Pacific and the El Niño–Southern Oscillation remaining in the neutral phase, with the possibility of a
La Niña La Niña (; ) is an oceanic and atmospheric phenomenon that is the colder counterpart of as part of the broader El Niño–Southern Oscillation (ENSO) climate pattern. The name ''La Niña'' originates from Spanish for "the girl", by an ...
developing.


Seasonal summary

Although the hurricane season in the eastern Pacific did not officially begin until May 15, and on June 1 in the central Pacific, activity this year began several weeks prior with the formation of Tropical Depression One-E on April 25. This marked the earliest formation of a tropical cyclone on record in the eastern Pacific basin, surpassing 2017's Tropical Storm Adrian. Among relatively unfavorable conditions, the depression soon dissipated without developing further, 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. 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. A short-lived tropical depression would form near
Baja California Sur Baja California Sur (; 'South Lower California'), officially the Free and Sovereign State of Baja California Sur ( es, Estado Libre y Soberano de Baja California Sur), is the least populated state and the 31st admitted state of the 32 federal ent ...
just 2 days after Boris's dissipation and quickly weaken. Moving into July, Tropical Storm Cristina formed on July 6 and slowly intensified to a peak intensity of , barely missing hurricane status. Activity continued as yet another tropical depression, Six-E, formed on July 13 but quickly dissipated among the unfavorable conditions unfolding in the basin. 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 15:00 UTC on July 22, marking the fourth–latest date any season had gone without a hurricane. Douglas would later strengthen into a
Category 4 hurricane Category, plural categories, may refer to: Philosophy and general uses *Categorization, categories in cognitive science, information science and generally *Category of being * ''Categories'' (Aristotle) *Category (Kant) *Categories (Peirce) *C ...
and brush Hawaii with rain and gusty winds. A burst of activity occurred in early August, with a
tropical wave A tropical wave (also called easterly wave, tropical easterly wave, and African easterly wave), in and around the Atlantic Ocean, is a type of atmospheric trough, an elongated area of relatively low air pressure, oriented north to south, which ...
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 Baja California Sur (; 'South Lower California'), officially the Free and Sovereign State of Baja California Sur ( es, Estado Libre y Soberano de Baja California Sur), is the least populated state and the 31st admitted state of the 32 federal ent ...
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 Nana, Nanna, Na Na or NANA may refer to: People and fictional characters * Nana (given name), including a list of people and characters with the given name * Nana (surname), including a list of people and characters with the surname * Nana (c ...
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 77.3 units. 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 .


Systems


Tropical Depression One-E

A disturbance developed within the
Intertropical Convergence Zone 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 the southeast trade winds converge. It encircles Earth near the thermal e ...
(ITCZ) on April 17, 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 Convection is single or multiphase fluid flow that occurs spontaneously due to the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity (see buoyancy). When the cause of the convec ...
, it was designated as Tropical Depression One-E at 06:00 UTC on April 25 about southwest of
Baja California Sur Baja California Sur (; 'South Lower California'), officially the Free and Sovereign State of Baja California Sur ( es, Estado Libre y Soberano de Baja California Sur), is the least populated state and the 31st admitted state of the 32 federal ent ...
. Moving northwestward, the depression retained organized deep convection until shortly after 00:00 UTC the next day. Dry air and westerly wind shear caused the depression to weaken and degenerate to a remnant low by 12:00 UTC. The remnant low turned west and opened up into a
trough Trough may refer to: In science * Trough (geology), a long depression less steep than a trench * Trough (meteorology), an elongated region of low atmospheric pressure * Trough (physics), the lowest point on a wave * Trough level (medicine), the l ...
at 18:00 UTC on April 27.


Tropical Storm Amanda

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 Guatemala ( ; ), officially the Republic of Guatemala ( es, República de Guatemala, links=no), is a country in Central America. It is bordered to the north and west by Mexico; to the northeast by Belize and the Caribbean; to the east by H ...
and
El Salvador El Salvador (; , meaning " The Saviour"), officially the Republic of El Salvador ( es, República de El Salvador), is a country in Central America. It is bordered on the northeast by Honduras, on the northwest by Guatemala, and on the south b ...
on May 27. Two days later, the system interacted with a
tropical wave A tropical wave (also called easterly wave, tropical easterly wave, and African easterly wave), in and around the Atlantic Ocean, is a type of atmospheric trough, an elongated area of relatively low air pressure, oriented north to south, which ...
that first originated from Africa on May 18. The conglomeration of these features led to the formation of a tropical depression around 18:00 UTC on May 30; it was positioned about south of
Puerto San José Puerto San José is a town on Guatemala's Pacific Ocean coast, in the department of Escuintla. It has a population of 23,887 (2018 census),
, Escuintla. Moving northeastward around the periphery of a large cyclonic gyre over northern
Central America Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...
, the compact depression continued to organize, strengthening into Tropical Storm Amanda at 06:00 UTC the next day. About four hours later, Amanda made landfall at peak intensity near Las Lisas,
Santa Rosa Santa Rosa is the Italian, Portuguese and Spanish name for Saint Rose. Santa Rosa may also refer to: Places Argentina *Santa Rosa, Mendoza, a city * Santa Rosa, Tinogasta, Catamarca * Santa Rosa, Valle Viejo, Catamarca *Santa Rosa, La Pampa * Sa ...
. Amanda rapidly degenerated as it moved inland, with its center dissipating around 18:00 UTC. The remnants of the system moved northward into the
Bay of Campeche The Bay of Campeche ( es, Bahía de Campeche), or Campeche Sound, is a bight (geography), bight in the southern area of the Gulf of Mexico, forming the north side of the Isthmus of Tehuantepec. It is surrounded on three sides by the Mexico, Mexic ...
and redeveloped into the Atlantic's
Tropical Storm Cristobal The name Cristobal has been used for four tropical cyclones in the Atlantic Ocean. Cristobal replaced the name Cesar after the 1996 season. * Tropical Storm Cristobal (2002), a relatively weak tropical storm causing only minor damage in Bermuda * ...
. In El Salvador, torrential rainfall caused significant damage along coastal cities in the country as rivers overflowed and swept away buildings. Amanda killed 14 people in El Salvador, of which at least six died due to flash flooding, and one died from a collapsed home. 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 A sinkhole is a depression or hole in the ground caused by some form of collapse of the surface layer. The term is sometimes used to refer to doline, enclosed depressions that are locally also known as ''vrtače'' and shakeholes, and to openi ...
. El Salvador President
Nayib Bukele Nayib Armando Bukele Ortez (; born 24 July 1981) is a Salvadoran politician and businessman who is the 43rd president of El Salvador, serving since 1 June 2019. He is the first president since José Napoleón Duarte (1984–1989) not to have ...
declared a 15-day national state of emergency due to the storm. 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.


Tropical Storm Boris

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 June 23. Deep convection coalesced with this circulation over the ensuing hours, and a tropical depression developed around 06:00 UTC on June 24. 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 The horse latitudes are the latitudes about 30 degrees north and south of the Equator. They are characterized by sunny skies, calm winds, and very little precipitation. They are also known as Subtropics, subtropical ridges, or highs. It is a h ...
. Nonetheless, it intensified into Tropical Storm Boris around 18:00 UTC on June 25 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 June 28, and Boris degenerated to a remnant area of low pressure by 00:00 UTC that day. The post-tropical cyclone curved west-southwest and dissipated well south-southeast of the
Hawaiian Islands The Hawaiian Islands ( haw, Nā Mokupuni o Hawai‘i) are an archipelago of eight major islands, several atolls, and numerous smaller islets in the North Pacific Ocean, extending some from the island of Hawaii in the south to northernmost Kur ...
on June 30.


Tropical Depression Four-E

A broad area of disturbed weather, at least partially enhanced by a tropical wave, formed near the Gulf of Tehuantepec on June 25. 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 18:00 UTC on June 29. Despite coalescing deeper convection near the center at the time of formation, Tropical Depression Four-E failed to attain winds greater than 30 mph (45 km/h) as it encountered hostile southwesterly wind shear and colder ocean waters. Instead, the system degenerated to a remnant area of low pressure by 18:00 UTC on June 30. The low turned north and dissipated well south of Baja California on July 1.


Tropical Storm Cristina

A tropical wave emerged off the west coast of Africa on June 20 and crossed into the East Pacific on July 3, where it interacted with the monsoon trough and began to organize. This system developed a defined surface low on July 6 and was classified as a tropical depression about 435 mi (705 km) south of
Acapulco Acapulco de Juárez (), commonly called Acapulco ( , also , nah, Acapolco), is a city and major seaport in the state of Guerrero on the Pacific Coast of Mexico, south of Mexico City. Acapulco is located on a deep, semicircular bay and has bee ...
, Guerrero. Steered along a northwest trajectory by a mid-level ridge, the depression traversed a region of favorable conditions which enabled slow intensification. Initial predictions from the NHC suggested significant strengthening of the cyclone. However, Cristina instead encountered cooler waters and eventually drier air; it reached its peak intensity late on July 10 with winds of 70 mph (110 km/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 18:00 UTC on July 12 and degenerated into a trough on July 15 about halfway between Hawaii and Baja California Sur.


Tropical Depression Six-E

A tropical wave, emerging off Africa on July 2, 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 July 13, a burst of extremely deep convection led to the redevelopment of a new circulation, and the system organized into a tropical depression around 12:00 UTC 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 18:00 UTC on July 14.


Unnamed Tropical Storm (Seven-E)

A tropical wave left Africa on July 6 and emerged into the East Pacific on July 13. It moved west and steadily coalesced despite an environment of cool ocean waters and dry air. At 00:00 UTC on July 20, 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 40 mph (65 km/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 06:00 UTC on July 21, The system degenerated to a remnant low. The low then spun down and dissipated by 00:00 UTC on July 22.


Hurricane Douglas

Douglas originated from a tropical wave that departed Africa on July 8. It reached the East Pacific on July 15, where environmental conditions fostered its development into a tropical depression at 00:00 UTC on July 20 about 805 mi (1,295 km) 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 18:00 UTC on July 22. A period of rapid intensification was underway at this point, and over a 30-hour period, its winds increased to 130 mph (215 km/h) on July 24. 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 July 27, the center of Douglas passed just 60 mi (95 km) north of Oahu; despite its proximity, effects were negligible. Increasing wind shear caused the hurricane to rapidly unfold on July 28, resulting in its degradation to a remnant low at 12:00 UTC 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 July 30.


Hurricane Elida

A tropical wave emerged off Africa on July 26 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 18:00 UTC on August 8. 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 August 9 and then rapidly the following day, attaining hurricane strength around 18:00 UTC on August 10. An eye developed within the storm's compact and symmetrical central dense overcast, and Elida reached peak winds of 105 mph (165 km/h) by 12:00 UTC 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 00:00 UTC on August 13 while positioned west of Baja California Sur. The low turned north before opening up into a trough a little over 24 hours later.


Tropical Depression Ten-E

An area of disturbed weather formed within the monsoon trough southwest of Baja California on August 11. It moved west and gradually organized, becoming a tropical depression at 06:00 UTC on August 13 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 35 mph (55 km/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 12:00 UTC on August 16. It opened up into a trough the next day.


Tropical Storm Fausto

A tropical wave entered the East Pacific on August 9 and spawned the development of a tropical depression around 00:00 UTC on August 16, 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 12:00 UTC on August 17, far away from land. The low moved west and opened up into a trough about a day later. A large plume of moisture brought northwards by Fausto generated massive thunderstorms across a large portion of
Northern California Northern California (colloquially known as NorCal) is a geographic and cultural region that generally comprises the northern portion of the U.S. state of California. Spanning the state's northernmost 48 counties, its main population centers incl ...
, beginning on August 16. 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 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. The massive SCU Lightning Complex, August Complex, CZU Lightning Complex, and
North Complex North Complex is a feature on Earth's Moon, a group of hills in the Hadley–Apennine region. It was an intended destination for the astronauts of the Apollo 15 mission, but due to problems extracting a rock core near the landing site, there wa ...
fires were connected to the thunderstorms associated with Fausto.


Hurricane Genevieve

A tropical wave crossed Central America on August 13, becoming the season's next tropical depression around 12:00 UTC on August 16 while located about south of Puerto Ángel,
Oaxaca Oaxaca ( , also , , from nci, Huāxyacac ), officially the Free and Sovereign State of Oaxaca ( es, Estado Libre y Soberano de Oaxaca), is one of the 32 states that compose the political divisions of Mexico, Federative Entities of Mexico. It is ...
. Favorable environmental conditions supported its rapid development while it moved northwest parallel to Mexico. It intensified into Tropical Storm Genevieve at 18:00 UTC on August 16 and became a hurricane around 12:00 UTC the next morning. Within the ensuing 24-hour period, Genevieve's maximum winds increased from 75 mph (120 km/h) to 130 mph (215 km/h), equivalent to a Category 4 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 18:00 UTC on August 21. It dissipated a little under a day later. Genevieve's close pass to Baja California Sur brought its strong winds onshore, with a peak sustained wind of and gust of observed at
Cabo San Lucas Cabo San Lucas (, "Saint Luke Cape"), or simply just Cabo, is a resort city at the southern tip of the Baja California Peninsula, in the Mexican state of Baja California Sur. As at the 2020 Census, the population of the city was 202,694 inhabitan ...
Marina. Isolated rainfall totals around overspread Oaxaca and Guerrero, and a storm-peak accumulation of occurred at Cabo San Lucas. Resultant flooding caused some damage to hydraulic, highway, and electrical systems throughout Baja California Sur; total damage topped $50 million. 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.


Tropical Storm Hernan

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 06:00 UTC on August 26. Broad in nature and under the influence of easterly wind shear, Hernan attained peak winds of 45 mph (75 km/h) on August 27 but began to rapidly weaken the next day as it moved north just offshore the Mexico coastline. It degenerated to a remnant low at 18:00 UTC on August 28. 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. In Mexico, 97,000 customers lost electricity. Hernan dropped heavy rainfall across southwestern Mexico, peaking at in Jalisco. causing flash flooding and mudslides in several states. At least 400 people were evacuated in Jalisco, and 18 people stuck on their roof in the state had to be rescued. In
Cihuatlán Cihuatlán is a coastal municipality in the Mexican state of Jalisco. Its main city is also named Cihuatlán. Etymology The word Cihuatlán is compounded of two words of Nahuatl origin, a language spoken in central Mexico since the seventh cent ...
, roughly 365 residents evacuated into shelters. A sinkhole shut down a portion of
Mexican Federal Highway 80 Federal Highway 80 (''Carretera Federal 80'') connects Tampico, Tamaulipas, to San Patricio, Jalisco. Federal Highway 80 connects the city of Guadalajara to the south coast in Jalisco. The highway runs through the towns of Acatlán de Juárez, V ...
between Santa Cruz and San Patricio, a mudslide closed down another part of the freeway near
Lázaro Cárdenas Lázaro Cárdenas del Río (; 21 May 1895 – 19 October 1970) was a Mexican army officer and politician who served as president of Mexico from 1934 to 1940. Born in Jiquilpan, Michoacán, to a working-class family, Cárdenas joined the M ...
. 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. Several schools were damaged by Hernan in the state of Colima. In Tamala, a parota tree fell on a road, blocking traffic. In Manzanillo, some homes and streets were damaged and covered with mud. In Nayarit, a mudslide occurred on a hill behind a populated neighborhood in Xalisco, however, no damage has been reported from this incident. Despite Hernan weakening into a tropical depression before landfall in
Baja California Sur Baja California Sur (; 'South Lower California'), officially the Free and Sovereign State of Baja California Sur ( es, Estado Libre y Soberano de Baja California Sur), is the least populated state and the 31st admitted state of the 32 federal ent ...
, local weather services in the area advised residents to take extreme precautions. Total damage from Hernan in Mexico was estimated at MXN$594.05 million pesos (US$26.91 million) by a federal Damage Assessment Committee.


Tropical Storm Iselle

Within the broad cyclonic circulation across Central America and adjacent waters, a westward-moving tropical wave spawned an area of low pressure on August 23. This low, originally weak and ill-defined, was enhanced by a CCKW two days later. Following increased organization, it became a tropical depression around 12:00 UTC on August 26 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 Deformation is the rate of change of shape of fluid bodies. Meteorologically, this quantity is very important in the formation of atmospheric fronts, in the explanation of cloud shapes, and in the diffusion of materials and properties.Djurić, D ...
that aided in deep convection. Iselle reached peak winds of 60 mph (95 km/h) early on August 28 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 18:00 UTC on August 30, and that low dissipated 24 hours later just offshore Baja California Sur.


Tropical Storm Julio

On September 3, the Atlantic's
Hurricane Nana The name Nana has been used for three tropical cyclones in the Atlantic Ocean. * Hurricane Nana (1990) – a Category 1 hurricane that never threatened land. * Tropical Storm Nana (2008) – short-lived weak tropical storm that remained at sea. * ...
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 85 mi (140 km) southwest of Puerto Angel, Oaxaca, at 00:00 UTC on September 5. The new storm moved unusually quick toward the west-northwest and reached peak winds of 45 mph (75 km/h) on September 6 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 06:00 UTC on September 7. The next day, its remnants were absorbed by a broad area of low pressure southwest of Socorro Island.


Tropical Storm Karina

A tropical wave departed Africa on August 26 and emerged into the East Pacific by September 7, where it only slowly developed. By 18:00 UTC on September 12, a new tropical depression formed about 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 06:00 UTC on September 13. Shear decreased the following day, allowing Karina to attain peak winds of 60 mph (95 km/h) on September 15. Ocean waters eventually began to decrease, causing a weakening trend that resulted in Karina's degeneration to a remnant low at 18:00 UTC on September 16. The low turned west and opened up into a trough early on September 18.


Tropical Storm Lowell

A trough developed south of the Atlantic's Tropical Storm Beta on September 28, 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 18:00 UTC on September 20. It was located about south-southeast of Baja California Sur then. Hostile wind shear initially prevented the depression from intensifying, but it lessened somewhat on September 21, allowing the system to become Tropical Storm Lowell around 18:00 UTC that day. Lowell attained peak winds of 50 mph (85 km/h) on September 23, 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 18:00 UTC on September 25. The low moved west and opened up into a trough on September 28 well east of the Big Island.


Hurricane Marie

A tropical wave interacted with the monsoon trough south of Mexico and an overarching CCKW, resulting in a broad disturbance on September 24. The system moved west-northwest, coalescing into a tropical depression around 06:00 UTC on September 29 while located about 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 00:00 UTC on October 1; within 30 hours, it reached its peak as a Category 4 hurricane with winds of 140 mph (220 km/h). Marie displayed a well-defined eye surrounded by cloud tops as cool as 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 18:00 UTC on October 6. A brief burst of convection nudged the low northward on October 7, but the cyclone curved west-southwest and opened up into a trough three days later, just after crossing into the Central Pacific.


Tropical Storm Norbert

A tropical wave left Africa on September 19 and moved over Central America on September 29. It gradually became more concentrated south of Mexico, developing into a tropical depression about southwest of Acapulco at 06:00 UTC on October 5. 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 60 mph (95 km/h) on October 6, 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 00:00 UTC on October 10, the system opened up into a trough south of Manzanillo. 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 18:00 UTC on October 13. It regained tropical storm status and reached a secondary peak of 45 mph (75 km/h) on October 14. 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 00:00 UTC on October 15 and dissipated less than 12 hours later to the west of Baja California Sur.


Tropical Storm Odalys

A tropical wave passed over Central America and entered the Eastern Pacific basin on October 29. Its associated thunderstorm activity remained relatively disorganized until November 1, when a broad area of low pressure developed within the system. By 18:00 UTC on November 3, the NHC determined the system was sufficiently organized to be designated Tropical Storm Odalys while it was centered about 730 mi (1,175 km) 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 00:00 UTC on November 5, the system reached its peak intensity with winds of 50 mph (85 km/h). Wind shear increased further shortly afterwards, causing Odalys to weaken quickly and eventually become a post-tropical cyclone at 18:00 UTC on November 5. Its shallow remnants turned southwest under the influence of a strong high-pressure area and dissipated by November 8.


Tropical Storm Polo

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 November 14, 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 18:00 UTC on November 17 to the southwest of Baja California Sur. The depression intensified into Tropical Storm Polo six hours later and reached peak winds of 45 mph (75 km/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 November 19. By 18:00 UTC 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 November 21.


Storm names

The following list of names was used for named storms that formed in the North Pacific Ocean east of 140°W during 2020. This is the same list used for the 2014 season, with the exception of the name Odalys, which replaced
Odile Odile is a feminine given name of French origin, and may refer to: Characters * Odile, the evil black swan of ''Swan Lake'' * Odile de Caray, in the 1966 film ''Eye of the Devil'' * Odile, a principal character in the 1964 Jean-Luc Godard film ' ...
. 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. For storms that form in the North Pacific from 140°W to the
International Date Line The International Date Line (IDL) is an internationally accepted demarcation on the surface of Earth, running between the South and North Poles and serving as the boundary between one calendar day and the next. It passes through the Pacific O ...
, 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. No storms formed within the area in 2020. Named storms in the table above that crossed into the area during the season are noted (*).


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.


See also

* Tropical cyclones in 2020 * Weather of 2020 *
2020 Atlantic hurricane season The 2020 Atlantic hurricane season featured a total of 31 tropical or subtropical cyclones, making it the most active Atlantic hurricane season on record. All but one cyclone became a named storm. Of the 30 named storms, 14 deve ...
*
2020 Pacific typhoon season The 2020 Pacific typhoon season was the first with below-average tropical cyclone activity since 2001, with 23 named storms, 10 of which became typhoons and only 2 became super typhoons. This low activity was a consequence of La Niña that per ...
*
2020 North Indian Ocean cyclone season The 2020 North Indian Ocean cyclone season was the costliest North Indian Ocean cyclone season on record, mostly due to the devastating Cyclone Amphan. The North Indian Ocean cyclone season has no official bounds, but cyclones tend to form betwe ...
* South-West Indian Ocean cyclone seasons: 2019–20,
2020–21 The dash is a punctuation mark consisting of a long horizontal line. It is similar in appearance to the hyphen but is longer and sometimes higher from the baseline. The most common versions are the endash , generally longer than the hyphen b ...
* Australian region cyclone seasons: 2019–20,
2020–21 The dash is a punctuation mark consisting of a long horizontal line. It is similar in appearance to the hyphen but is longer and sometimes higher from the baseline. The most common versions are the endash , generally longer than the hyphen b ...
* South Pacific cyclone seasons: 2019–20,
2020–21 The dash is a punctuation mark consisting of a long horizontal line. It is similar in appearance to the hyphen but is longer and sometimes higher from the baseline. The most common versions are the endash , generally longer than the hyphen b ...


Notes


References


External links


National Hurricane Center WebsiteNational Hurricane Center's Eastern Pacific Tropical Weather OutlookServicio Meteorológico Nacional Website

Joint Typhoon Warning Center

NHC 2020 Pacific hurricane season archive
{{Tropical cyclone season, 2020 Pacific hurricane seasons Tropical cyclones in 2020