There have been 24 recorded tropical and subtropical cyclones in the eastern Pacific basin outside the official Pacific hurricane season. The National Hurricane Center (NHC) monitors the area from North America westward to 140°W, while the Central Pacific Hurricane Center is from 140°W to the International date line, north of the equator. The National Oceanic and Atmospheric Administration (NOAA) currently defines the season as starting May 15 in the eastern Pacific and June 1 for the central Pacific and ending on November 30 for both regions in each calendar year. Occasionally, however, storms develop in late November and persist until December, such as Hurricane Nina of 1957.
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".
A subtropical cyclone is a weather system that has some characteristics of a tropical and an extratropical cyclone.
Traditionally, areas of tropical cyclone formation are divided into seven basins. These include the north Atlantic Ocean, the eastern and western parts of the northern Pacific Ocean, the southwestern Pacific, the southwestern and southeastern Indian Oceans, and the northern Indian Ocean. The western Pacific is the most active and the north Indian the least active. An average of 86 tropical cyclones of tropical storm intensity form annually worldwide, with 47 reaching hurricane/typhoon strength, and 20 becoming intense tropical cyclones, super typhoons, or major hurricanes.
Few off-season tropical cyclones in the east Pacific have affected land, and none of them have made landfall. 115 mph (185 km/h). However, after Tropical Storm Paka crossed the International Date Line, it intensified into a typhoon with winds equivalent to a Category 5 hurricane on the Saffir-Simpson hurricane wind scale. The most recent off-season storm is Tropical Depression One-E in early-May 2018.Only Hurricane Nina caused both property damage and fatalities. The strongest hurricane between December and May was Hurricane Ekeka in 1992, which reached winds of
Hurricane Ekeka was the most intense off-season tropical cyclone on record in the north-eastern pacific basin. The first storm of the 1992 Pacific hurricane season, Ekeka developed on January 28 well to the south of Hawaii. It gradually intensified to reach major hurricane status on February 2, although it subsequently began to weaken due to unfavorable wind shear. It crossed the International Date Line as a weakened tropical storm, and shortly thereafter degraded to tropical depression status. Ekeka continued westward, passing through the Marshall Islands and later over Chuuk State, before dissipating on February 9 about 310 miles (500 km) off the north coast of Papua New Guinea. The storm did not cause any significant damage or deaths.
The 1992 Pacific hurricane season was the most active Pacific hurricane season on record, featuring 27 named storms, and the second-costliest Pacific hurricane season in history, behind only the 2013 season. The season also produced the second-highest ACE value on record in the basin, surpassed by the 2018 season. The season officially started on May 15 in the eastern Pacific, and on June 1 in the central Pacific, and lasted until November 30. These dates conventionally delimit the period of each year when most tropical cyclones form in the northeastern Pacific Ocean. However, these bounds were easily exceeded when Hurricane Ekeka formed on January 28 and again a couple months later with Tropical Storm Hali.
Typhoon Paka, known in the Philippines as Typhoon Rubing, was the last tropical cyclone of the 1997 Pacific hurricane and typhoon season, and was among the strongest Pacific typhoons in the month of December. Paka, which is the Hawaiian name for Pat, developed on November 28 from a trough well to the southwest of Hawaii. The storm tracked generally westward for much of its duration, and on December 7 it crossed into the western Pacific Ocean. Much of its track was characterized by fluctuations in intensity, and on December 10 the cyclone attained typhoon status as it crossed the Marshall Islands. On December 16, Paka struck Guam and Rota with winds of 230 km/h (145 mph), and it strengthened further to reach peak winds on December 18 over open waters as the final super typhoon of the year. Subsequently, it underwent a steady weakening trend, and on December 23 Paka dissipated.
The beginning of HURDAT, the official Pacific hurricane database maintained by the NHC, is 1949. Since then, thirteen storms have occurred 2,000 mi (3,220 km) off the Mexican coastline, including one in December.outside the official bounds of hurricane season in the eastern and central north Pacific, respectively. In addition, the CPHC reports nine off-season storms from 1900–1952 with another off-season tropical cyclone occurring in 1832. There have been documents published in the Monthly Weather Review reporting additional off-season storms within
The Hurricane Databases (HURDAT), managed by the National Hurricane Center, are two separate databases that contain details on tropical cyclones, that have occurred within the Atlantic Ocean and Eastern Pacific Ocean since either 1851 or 1949.
The Monthly Weather Review is a peer-reviewed scientific journal published by the American Meteorological Society. It covers research related to analysis and prediction of observed and modeled circulations of the atmosphere, including technique development, data assimilation, model validation, and relevant case studies. This includes papers on numerical techniques and data assimilation techniques that apply to the atmosphere and/or ocean environment. The editor-in-chief is David M. Schultz.
The wind speeds listed are maximum one-minute average sustained winds. The category refers to the intensity on the Saffir–Simpson hurricane wind scale; TS stands for tropical storm, and TD for tropical depression.
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.
Tropical cyclones are unofficially ranked on one of five tropical cyclone intensity scales, according to their maximum sustained winds and which tropical cyclone basin(s) they are located in. Only a few scales of classifications are used officially by the meteorological agencies monitoring the tropical cyclones, but some alternative scales also exist, such as accumulated cyclone energy, the Power Dissipation Index, the Integrated Kinetic Energy Index, and the Hurricane Severity Index.
|Storm||Season||Duration||Peak classification|| Maximum|
|"Froc Cyclone"||1902||December 23, 1902 – January 2, 1903||Unknown||Unknown|
|"Zikawei Cyclone"||1904||November 26 – December 4||Unknown||Unknown|
|"Hurd Cyclone"||1904||December 23–30||Unknown||Unknown|
|"Gauthier Cyclone"||1906||May 3–10||Unknown||Unknown|
|Unnamed||1938||January 2–5||Unknown||Unknown||The Monthly Weather Review was uncertain if the storm was a tropical cyclone|
|Nina||1957||November 29 – December 6||Category 1 hurricane||85 mph (140 km/h)||Caused $100,000 in damage and four fatalities in Hawaii|
|Carmen||1980||April 4–8||Tropical storm||50 mph (80 km/h)|
|Winnie||1983||December 4–7||Category 1 hurricane||90 mph (150 km/h)||Strongest east Pacific tropical cyclone in the month of December|
|Winona||1989||January 9–15||Tropical storm||45 mph (75 km/h)|
|Alma||1990||May 12–20||Category 1 hurricane||85 mph (140 km/h)|
|Ekeka||1992||January 28 – February 3||Category 3 hurricane||115 mph (185 km/h)||Strongest off-season east Pacific tropical cyclone|
|Hali||1992||March 28–30||Tropical storm||50 mph (80 km/h)|
|One-E||1996||May 13–16||Tropical storm||50 mph (80 km/h)||Assumed to have caused two deaths after the ship Solar Wind was lost at sea|
|Paka||1997||December 2–7||Tropical storm||65 mph (100 km/h)||Later became a super typhoon in the West Pacific|
|Omeka||2010||December 18–22||Tropical storm||60 mph (95 km/h)||Was subtropical from December 18 – 20 in central Pacific, was in the western Pacific from December 20 – 22, and tropical on December 22 onward in the central Pacific|
|Aletta||2012||May 14–19||Tropical storm||50 mph (80 km/h)|
|Nine-C||2015||December 31||Tropical depression||35 mph (55 km/h)||Latest formation of a tropical cyclone in the eastern Pacific basin.|
|Pali||2016||January 7 – January 15||Category 2 hurricane||100 mph (155 km/h)||Earliest formation of a tropical cyclone in the eastern Pacific basin.|
|Adrian||2017||May 9–10||Tropical storm||45 mph (75 km/h)||Earliest formation of a tropical cyclone in the eastern Pacific basin proper (east of 140°W).|
|One-E||2018||May 10–11||Tropical depression||35 mph (55 km/h)||2nd Earliest formation of a tropical cyclone in the eastern Pacific basin proper (east of 140°W).|
Several off-season tropical cyclones have affected land. Hurricane Nina in early December 1957 prompted evacuations in Hawaii and caused $100,000 (1957 USD) in damage in the state. The storm also killed four people and produced 35 ft (10 m) waves. Hurricane Winnie in December 1983 caused minor rainfall in parts of Mexico. The unnamed tropical storm of 1996 was assumed to have killed two people when it sank a trimaran called the Solar Wind. After becoming a typhoon, Paka caused significant damage in the Marshall Islands, Guam, and the Northern Mariana Islands. Overall, Paka caused $580 million (1997 USD) in damage, enough to warrant retirement of the name. None of these impacting systems made landfall.
The Marshall Islands, officially the Republic of the Marshall Islands, is an island country and a United States associated state near the equator in the Pacific Ocean, slightly west of the International Date Line. Geographically, the country is part of the larger island group of Micronesia. The country's population of 53,158 people is spread out over 29 coral atolls, comprising 1,156 individual islands and islets.
Guam is an unincorporated and organized territory of the United States in Micronesia in the western Pacific Ocean. It is the easternmost point and territory of the United States, along with the Northern Mariana Islands. The capital city of Guam is Hagåtña and the most populous city is Dededo. The inhabitants of Guam are called Guamanians, and they are American citizens by birth. Indigenous Guamanians are the Chamorros, who are related to other Austronesian natives of Eastern Indonesia, the Philippines, and Taiwan. Guam has been a member of the Pacific Community since 1983.
The Northern Mariana Islands, officially the Commonwealth of the Northern Mariana Islands, is an insular area and commonwealth of the United States consisting of 14 islands in the northwestern Pacific Ocean. The CNMI includes the 14 northernmost islands in the Mariana Archipelago except the southernmost island of the chain, Guam, which is a separate U.S. territory. The CNMI and Guam are the westernmost point and territory of the United States.
In the official east Pacific hurricane database, which dates back to 1949, the first storm to occur outside of the current season was Hurricane Nina in 1957. In the database, thirteen tropical cyclones have existed between December and May, most recently Hurricane Pali in 2016. 1989 was not listed in the database, despite forming south of Hawaii. In addition, there were at least eight tropical cyclones before the start of the official database, many of which existed near Hawaii. Storms were most likely to occur in December, followed by January and May. Only one cyclone each was reported in the two months of March and April. Of all off-season tropical cyclones, the "Froc Cyclone" lasted longest, spanning 12 days and two calendar years. The year with the most off-season storms was tied between 1904 and 1992, with a total of two tropical cyclones. No Pacific hurricane season had both a pre-season and post-season storm.Tropical Storm Winona in January
The 1979 Atlantic hurricane season was the first season to include both male and female names, as well as the common six-year rotating lists of tropical cyclone names. The season officially began on June 1, and lasted until November 30. These dates conventionally delimit the period of each year when most tropical cyclones form in the Atlantic basin. It was slightly below average, with nine systems reaching tropical storm intensity. The first system, an unnumbered tropical depression, developed north of Puerto Rico on June 9. Two days later, Tropical Depression One formed and produced severe flooding in Jamaica, with 40 deaths and about $27 million (1979 USD) in damage. Tropical Storm Ana caused minimal impact in the Lesser Antilles. Hurricane Bob spawned tornadoes and produced minor wind damage along the Gulf Coast of the United States, primarily in Louisiana, while the remnants caused flooding, especially in Indiana. Tropical Storm Claudette caused extensive flooding, due to torrential rainfall. There were two deaths and damaged totaled $750 million.
Hurricane Kenna was at the time tied as the second-most intense Pacific hurricane to strike the west coast of Mexico. Kenna was the sixteenth tropical depression, thirteenth tropical storm, seventh hurricane, sixth major hurricane, and third Category 5 hurricane of the 2002 Pacific hurricane season. After forming on October 22 to the south of Mexico from a tropical wave, forecasters consistently predicted the storm to strengthen much less than it actually did. Moving into an area of favorable upper-level conditions and warm sea surface temperatures, Kenna quickly strengthened to reach peak winds of 165 mph (270 km/h) as a Category 5 hurricane, on October 25, while located about 255 mi (410 km) southwest of Puerto Vallarta, Jalisco. Weakening as it turned to the northeast, the hurricane made landfall near San Blas, Nayarit as a Category 4 hurricane, with sustained winds of 140 mph (220 km/h), before dissipating on October 26 over the Sierra Madre Occidental mountains.
The 1911 Atlantic hurricane season was relatively inactive, with only six known tropical cyclones forming in the Atlantic during the summer and fall. There were three suspected tropical depressions, including one that began the season in February and one that ended the season when it dissipated in December. Three storms intensified into hurricanes, two of which attained Category 2 status on the modern-day Saffir–Simpson Hurricane Scale. Storm data is largely based on the Atlantic hurricane database, which underwent a thorough revision for the period between 1911 and 1914 in 2005.
A Pacific hurricane is a mature tropical cyclone that develops within the eastern and central Pacific Ocean to the east of 180°W, north of the equator. For tropical cyclone warning purposes, the northern Pacific is divided into three regions: the eastern, central, and western, while the southern Pacific is divided into 2 sections, the Australian region and the southern Pacific basin between 160°E and 120°W. Identical phenomena in the western north Pacific are called typhoons. This separation between the two basins has a practical convenience, however, as tropical cyclones rarely form in the central north Pacific due to high vertical wind shear, and few cross the dateline.
Hurricane Nina was the final tropical storm and hurricane of the 1957 Pacific hurricane season and the last storm to form during the active Central Pacific hurricane season this year. This storm was named "Nina" because during this time, hurricanes in this basin were given names from the typhoon naming lists. This storm was the last to form during a series of typhoons to form in the Pacific in November.
Hurricane Hiki was the third-wettest tropical cyclone on record in the United States, behind Hurricane Lane in 2018, and Hurricane Harvey in 2017. It was also considered the first official hurricane in the vicinity of the Hawaiian Islands. The fourth tropical cyclone of the 1950 Pacific hurricane season, Hiki formed as a tropical depression to the southeast of Hawaii on August 12. On the following day, the depression headed northwestward and intensified into Tropical Storm Hiki. While paralleling the Hawaiian Islands on August 16, Hiki strengthened into a hurricane. Around that time, the storm peaked with maximum sustained winds of 85 mph (140 km/h). The following day, Hiki curved southwestward on August 17. Two days later, the hurricane resumed moving northwestward and weakened to a tropical storm shortly thereafter. Around midday on August 21, Hiki weakened to a tropical depression and dissipated about six hours later.
Hurricane Dora was the strongest tropical cyclone in the northeastern Pacific in 2011. Dora developed from a tropical wave south of Honduras on July 18. Moving northwestward in favorable conditions, the system quickly intensified to tropical storm status and attained hurricane intensity the next day. Rapid intensification ensued shortly thereafter, bringing the storm to its peak intensity on July 21 as a Category 4 hurricane, with a minimum barometric pressure of 929 mbar and maximum sustained winds of 155 mph (250 km/h). However, the storm's path into an area with cool sea surface temperatures and wind shear caused Dora to quickly deteriorate and weaken. By July 24, Dora had degenerated into a remnant low-pressure area west of the Baja California Peninsula. Dora brought stormy conditions to the southwestern Mexico coast and the Baja California Peninsula throughout its existence. Remaining off the coast from its formation to dissipation, Dora's effects on land were slight. However, the outer rainbands of the hurricane caused flooding and mudslides in southern Mexico and Guatemala, while rough surf toppled a lighthouse and damaged 60 restaurants along the coast. The hurricane's remnants contributed to heightened shower and thunderstorm activity across New Mexico and Arizona in late July.
The 2018 Pacific hurricane season produced the highest accumulated cyclone energy (ACE) value on record in the Eastern Pacific basin. 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.