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1990 Pacific hurricane season

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1990 Pacific hurricane season
Season summary map
Seasonal boundaries
First system formedMay 12, 1990
Last system dissipatedOctober 31, 1990
Strongest storm
NameTrudy
 • Maximum winds155 mph (250 km/h)
(1-minute sustained)
 • Lowest pressure924 mbar (hPa; 27.29 inHg)
Seasonal statistics
Total depressions26
Total storms21
Hurricanes16
Major hurricanes
(Cat. 3+)
6
Total fatalities0
Total damageUnknown
Pacific hurricane seasons
1988, 1989, 1990, 1991, 1992

The 1990 Pacific hurricane season was the second most active season behind the 1992 season. The 1990 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 slightly exceeded when Hurricane Alma formed on May 12.[1]

Hurricane Alma became the earliest hurricane since the satellite era began, while Trudy remains the second strongest October eastern Pacific hurricane on record. Tropical Storm Rachel made two landfalls in Mexico and brought rain to the United States. Overall, the impact of this season was minimal. Hurricane Boris brought some showers to California.[2]

Season Summary

Saffir-Simpson Hurricane Scale
Hurricanes Hernan (top-left), Iselle (top-right) and Tropical Depression Eleven-E (bottom-right) on July 25, 1990

The 1990 eastern North Pacific hurricane season was active in terms of number of storms that attained at least tropical storm intensity and of Accumulated Cyclone Energy. The season's tropical cyclones all developed from westward-moving African tropical waves. The season established several tropical storm records for this basin and was marked by several strong hurricanes. There were 20 named tropical cyclones, four below the record established by the 1992 Pacific hurricane season two years later, but four more than the long-term average. Sixteen of those named storms, twice the average and four more than the previous record, reached hurricane intensity. Only Cristina, Douglas, Aka, Rachel, and Simon did not reach hurricane strength. Six of those hurricanes reached Category 3 intensity or higher on the Saffir-Simpson Hurricane Scale. Hurricanes Hernan and Trudy were among the strongest ever observed in this area. Alma became the earliest named tropical cyclone for the eastern Pacific ocean east of the 140th meridian west. The eastern Pacific produced four tropical depressions that did not reach tropical storm status.[1]

With the exception of Marie and Polo, these systems developed between and 15°N, east of the longitude of Baja California in the climatologically favored area for tropical cyclogenesis. After their development, most of the tropical cyclones moved on a west to northwest track and dissipated over cool waters without affecting land. Rachel was the only system to make landfall. One tropical storm formed in the Central Pacific and eventually crossed the dateline before dissipating.[2]

Storms

Twenty-four tropical cyclones, including four tropical depressions that failed to attain tropical storm status, developed in the Eastern Pacific Ocean and two tropical cyclones, including one tropical depression that did not strengthen into a tropical storm, formed in the Central Pacific Ocean in 1990.

Hurricane Alma

Category 1 hurricane (SSHWS)
 
DurationMay 12 – May 18
Peak intensity85 mph (140 km/h) (1-min);
979 mbar (hPa)

A tropical wave emerged from Africa on April 29. It then moved across the Atlantic, crossed northern South America, and entered the Pacific Ocean on May 9. Convection started to increase with the wave just to the south of Panama. The wave moved westward and continued to become better organized over the next few days. On May 12, the wave had become organized enough and was designated Tropical Depression One-E.[3]

Tropical Depression One-E moved slowly to the northwest while strengthening slowly due to easterly vertical wind shear. The depression was upgraded to Tropical Storm Alma on May 14. The storm quickly strengthened once the vertical wind shear relaxed and was near hurricane force by the morning of May 15. Hurricane Alma reached its peak intensity early on May 16 with maximum sustained winds of 85 mph (135 km/h). The hurricane entered an area of southwesterly wind shear caused by an upper-level ridge of high pressure. The increasing vertical wind shear and cooler water caused Alma to weaken to a tropical storm. On May 17, the storm continued to weaken and became a depression. The next day, the system dissipated as a tropical cyclone well west of mainland Mexico.[3][4][5][6] Alma became the earliest named storm and hurricane in the satellite era.[3][7]

Hurricane Boris

Category 1 hurricane (SSHWS)
 
DurationJune 2 – June 8
Peak intensity90 mph (150 km/h) (1-min);
977 mbar (hPa)

A tropical wave came off the northwest coast of Africa on May 20. The wave did not significantly develop as it moved west across the Atlantic Ocean and Caribbean Sea. Once it crossed Central America into the eastern Pacific Ocean, cloudiness increased considerably with the system on May 31.[8] It became well-enough organized to be upgraded to Tropical Depression Two-E on June 2. After becoming a depression, the system moved to the west-northwestward. Upper-level easterly vertical wind shear limited the amount of the initial strengthening. However, an increase in convective banding led to its upgrade to Tropical Storm Boris on June 4, 435 nautical miles (806 km) southwest of Manzanillo. An anticyclone aloft fostered additional development. By June 5, Boris became a hurricane. The hurricane began to move to the north-northwest in response to a trough off of the West Coast of the United States. Strengthening continued, and the storm reached its peak strength with winds of 90 miles per hour (140 km/h) and a minimum central pressure of 977 millibars (28.9 inHg). The winds in the eyewall of Boris ripped off the sails of the Azzure Dream sailboat. No other direct damages or casualties were reported from Boris.[8][9][10]

The hurricane's cloud pattern became elongated along a southwest-northeast axis on June 6 due to an increased amount of vertical wind shear. Boris was downgraded to a tropical storm later in the day on June 6. The deep convection of the tropical storm decreased, as Boris moved over cooler waters. It was downgraded to a tropical depression on June 7 due to these factors. The depression dissipated as a tropical cyclone on June 8 as the system quickly lost its tropical characteristics. A small circulation remained in the cloud field offshore the northwest coast of Baja California for a few more days.[8][11] Boris' remnants brought rain to the Southwest. Despite causing the wettest June in San Diego since records began in 1850, not even an inch of rain fell at that location.[9][12]

Tropical Storm Cristina

Tropical storm (SSHWS)
 
DurationJune 8 – June 16
Peak intensity65 mph (100 km/h) (1-min);
994 mbar (hPa)

A tropical wave came off the coast of Africa on May 23. It crossed the Atlantic Ocean with minimal development as it moved westward. The wave moved across Central America into the northeastern Pacific Ocean, where convection organized with the system on June 6. The system became well-enough organized to be upgraded to Tropical Depression 3-E on June 8, while 800 nautical miles (1,500 km) south of the southern tip of Baja California. The depression continued to strengthen, and was upgraded to Tropical Storm Cristina on June 9.[13][14]

Cristina initially had well-established upper-level outflow. It failed to reach hurricane status, peaking with maximum sustained winds of 65 miles per hour (105 km/h) due to movement of its associated upper-level anticyclone to the north over Mexico which caused Cristina to be exposed to easterly vertical wind shear. Cristina moved generally northwestward, which eventually placed the storm in cooler waters, and caused the deep convection of the system to dissipate. On June 14, Cristina diminished to a tropical depression. Tropical Depression Cristina moved west-northwestward with the low-level flow. The depression dissipated as a tropical cyclone on June 16, after a lack of deep convection for 48 hours.[13][15]

Tropical Storm Douglas

Tropical storm (SSHWS)
 
DurationJune 19 – June 23
Peak intensity65 mph (100 km/h) (1-min);
992 mbar (hPa)

A tropical wave moved off the northwest coast of Africa on June 5. It continued westward across the tropical North Atlantic and Caribbean Sea without significant development.[16] The wave entered the northeastern Pacific Ocean on June 16, where it generated an area of increased cloudiness. Organization of thunderstorm activity increased late on June 18 and early on June 19. Tropical Depression Four-E formed on June 19, when it was 200 nautical miles (370 km) south of Acapulco, Mexico after evidence of low-level circulation for the past 24 hours. The depression moved in a west-northwest direction, due to a subtropical ridge north of the depression. Satellite analysis indicated that the depression had reached tropical storm force strength, and it was upgraded to Tropical Storm Douglas on June 19, while 200 nautical miles (370 km) southwest of Acapulco. Douglas reached peak strength of 65 miles per hour (105 km/h) on June 21[16][17]

A tropical storm warning was issued on June 21, from Punta Tejupan to Cabo Corrientes before being discontinues on June 22. Tropical Storm Douglas brushed the western coast of Mexico. The center of circulation approached within 15 nautical miles (28 km) of the coast of Mexico on June 22. Douglas then began to weaken because of interaction with the mountainous terrain of Mexico. The system continued to weaken despite warm water temperatures and favorable upper-level conditions. Douglas dissipated early on June 24, while 120 nautical miles (220 km) south-southeast of the southern tip of Baja California. The highest rainfall report from Mexico from Douglas totaled 11.07 inches (281 mm) at La Huerta.[18] No deaths or damage were reported.[16][19]

Hurricane Elida

Category 1 hurricane (SSHWS)
 
DurationJune 26 – July 2
Peak intensity80 mph (130 km/h) (1-min);
990 mbar (hPa)

A tropical wave came off the coast of Africa into the eastern Atlantic Ocean on June 10 and 11. The system moved across the Atlantic and entered into the northeastern Pacific Ocean.[20] The wave became a significant tropical system, with cyclonic turning in the lower and middle layers of the system's cloudiness on June 25. The center of circulation was located 300 nautical miles (560 km) south of Acapulco, Mexico. The system exhibited sufficient organization to be considered Tropical Depression 5-E on June 26. The depression quickly strengthened and became Tropical Storm Elida later that day. The track of Elida was west-northwestward to northwestward from June 27 through June 28. Some rainbands moved over the mountainous region of southwestern Mexico, but no flooding, damage, or casualties were reported as a result. Elida continued strengthening and it was upgraded to a hurricane early on June 28 passing directly over Socorro Island later in the day, right as Elida reached peak strength of 80 miles per hour (130 km/h), dropping 3.7 inches, 94.4 mm of rain on the island. Some windows broke also as a result, and minor structural damage was reported as a result on the island.[20][21]

A high-pressure area to the north forced Elida to move more westward on June 29. Convection began to decrease in the hurricane as it moved into cooler waters, and it weakened to a tropical storm later in the day. It then weakened to a tropical depression on July 1, and dissipated on July 2.[20][22]

Tropical Depression Six-E

Tropical depression (SSHWS)
 
DurationJune 29 – July 4
Peak intensity35 mph (55 km/h) (1-min);

An area of disturbed weather south of Acapulco organized into Tropical Depression Six-E on June 29 and the system began to move northwest. Originally the system was expected to reach tropical storm strength but the persistent vertical wind shear over the system impeded its development. The depression subsequently dissipated on July 4.[23]

Hurricane Fausto

Category 1 hurricane (SSHWS)
 
DurationJuly 6 – July 12
Peak intensity85 mph (140 km/h) (1-min);
979 mbar (hPa)

A tropical wave came off the northwest coast of Africa on June 19. The wave crossed the Atlantic Ocean and Caribbean Sea, into the warm waters of the northeastern Pacific Ocean, on July 2.[24] An area of disturbed weather moved northwards towards the Gulf of Tehuantepec and became Tropical Depression Seven-E early on July 6. The depression moved northwest, and because of increased organization of deep convection, was designated Tropical Storm Fausto on July 7, 230 nautical miles (430 km) south of Manzanillo, Mexico. A weakly defined eye formed on July 8, and the storm was upgraded to Hurricane Fausto, 270 nautical miles (500 km) south of Cabo San Lucas.

Fausto peaked in strength with winds of 85 miles per hour (137 km/h) and a central pressure of 979 millibars (28.9 inHg) on July 9. Fausto passed 35 nautical miles (65 km) north of Socorro Island causing a northwest wind of 40 miles per hour (64 km/h), and 4.3 inches (110 mm) of rain at that location. The hurricane fluctuated in intensity on July 10,[24][25] before weakening into a tropical storm later that day, 350 nautical miles (650 km) west of Cabo San Lucas. The weakening Fausto moved over continuing cooler waters, and was downgraded to a tropical depression on June 11, 600 nautical miles (1,100 km) west of Cabo San Lucas. The depression dissipated as a tropical cyclone on June 13, and its low level circulation of clouds persisted for a few days.[24]

Hurricane Genevieve

Category 2 hurricane (SSHWS)
 
DurationJuly 10 – July 18
Peak intensity105 mph (165 km/h) (1-min);
970 mbar (hPa)

A tropical wave moved off the coast of Africa on June 25 and moved across the Atlantic Ocean and central Caribbean Sea with little development. Within the western Caribbean Sea, convection developed with the wave on July 7.[26] The system became better organized as it moved into the northeastern Pacific Ocean. The system was upgraded to Tropical Depression 8-E on July 11. The depression moved west-northwest, with a good outflow to the north, and gradually strengthened into Tropical Storm Genevieve later that day. Genevieve continued to strengthen, reaching hurricane strength on July 13. The storm approached within 20 nautical miles (37 km) of Socorro Island where a sustained wind of 44 miles per hour (71 km/h) and gust of 50 miles per hour (80 km/h) were reported, before the weather equipment on the island failed.

The hurricane began to turn west because of the strengthening and growing ridge to its north. Increasing outflow aloft began to form, and the hurricane reached its peak strength of 105 miles per hour (169 km/h) with a well-defined eye at its center of circulation.[26][27][28] Genevieve turned northwest on July 16 into an area with strong vertical wind shear and low water temperatures. The hurricane quickly weakened into a tropical storm on July 17 and then into a tropical depression on July 18. Genevieve dissipated as a tropical cyclone later in the day, reduced to a circulation in the stratocumulus cloud field.[26]

Hurricane Hernan

Category 4 hurricane (SSHWS)
 
DurationJuly 19 – July 31
Peak intensity155 mph (250 km/h) (1-min);
928 mbar (hPa)

A tropical wave that moved off the northwest coast of Africa on July 4 passed through the Atlantic Ocean and Caribbean Sea without significant development.[29] The wave moved across Central America into the northeastern Pacific Ocean on July 15. Thunderstorm activity increased in the system between July 16 and 18 before rainbands became present within the tropical disturbance on July 19. Tropical Depression Nine-E formed later that day while 490 nautical miles (910 km) southwest of Acapulco, Mexico.[1]

Tropical Depression Nine-E strengthened into Tropical Storm Hernan on July 21 while 600 nautical miles (1,100 km) south of Cabo San Lucas. The tropical storm continued to strengthen and as it moved to the northwest, and became a hurricane late on July 21. Hernan continued to strengthen and as it passed while 125 nautical miles (232 km) southwest of Clarion Island, and 220 nautical miles (410 km) south-southwest of Socorro Island. On July 23, Hernan reached its peak strength of 155 miles per hour (249 km/h) and minimum pressure of 928 millibars (27.4 inHg) as the center of circulation was 180 nautical miles (330 km) south-southwest of Clarion Island. On July 24, concentric eyewalls (one eyewall located inside another) formed around the center of Hernan, which was the first time this pattern had been observed with an eastern Pacific hurricane.[29][30]

Hernan kept Category 4 hurricane intensity for four more days and hurricane strength for six days overall. The hurricane weakened into a tropical storm on July 28 as it moved over cooler waters. Hernan turned more to the west as its low level center became separated from its thunderstorm activity and was steering by a surface high-pressure system to its north. Hernan moved over cooler waters, dissipating as a tropical cyclone early on July 31.[29][31]

Hurricane Iselle

Category 3 hurricane (SSHWS)
 
DurationJuly 20 – July 30
Peak intensity120 mph (195 km/h) (1-min);
958 mbar (hPa)

A tropical wave moved off the coast of Africa on July 7. The wave moved west, but it was not until it moved across the Caribbean Sea that the wave's convection organized.[32] The system entered into the northeastern Pacific Ocean with concentrated convection and a surface center of circulation while southeast of Acapulco. Moving west-northwest, Tropical Depression Ten-E formed on July 20 and developed into Tropical Storm Iselle the next day. The storm continued strengthening while in the proximity of Hurricane Hernan, becoming a hurricane on July 22.[1]

The hurricane continued to move west-northwest through its lifespan, and reached its peak strength of 120 miles per hour (190 km/h) on July 25. Iselle's track came close to Socorro Island, which recorded a 70 mph (110 km/h) sustained wind and heavy rain on July 25.[32][33][34] The hurricane weakened on following days after it moved over cooler waters, downgraded to a tropical storm on July 28 and subsequently into a tropical depression on July 30. The depression dissipated later that day, after losing its low-level circulation.[32][34][35]

Tropical Depression Eleven-E

Tropical depression (SSHWS)
 
DurationJuly 24 – July 26
Peak intensity30 mph (45 km/h) (1-min);

On July 24 a tropical disturbance behind Hurricane Hernan strengthened into a tropical depression. Due to its nearness of the hurricane to its west, the development of the depression was hindered due to vertical wind shear from the outflow of Hernan. This wind shear dissipated the depression on July 26, and its remnants were absorbed by the nearby cyclone. No damages or casualties were caused by the depression as it was well out to sea.[36]

Tropical Storm Aka

Tropical storm (SSHWS)
 
DurationAugust 7 – August 15
Peak intensity65 mph (100 km/h) (1-min);
Unknown mbar (hPa)

Tropical Storm Aka was the only tropical storm to form in the central North Pacific during 1990. An area of disturbed weather began to organize on August 6. By August 7, the system became well-enough organized to become designated Tropical depression One-C. The depression intensified into a tropical storm while moving west, to the south of the Hawaiian Islands. On August 10, Tropical Storm Aka peaked with maximum sustained winds of 60 miles per hour (97 km/h). The storm continued to move west and approached Johnston Island, though the island's weather did not deteriorate. The tropical storm crossed the International Date Line on August 13.[37] Aka weakened back into a depression and dissipated two days later on August 15.[1]

Tropical Depression Two-C

Tropical depression (SSHWS)
 
DurationAugust 10 – August 13
Peak intensity35 mph (55 km/h) (1-min);

Tropical Depression Two-C was the second and last tropical cyclone to form in the north-central Pacific Ocean. The depression formed from a tropical disturbance well southeast of Hawaii which became much better organized on the night of August 10. The tropical depression moved in a west northwest direction for the next 18 hours and then changed to a west-southwest track on August 11. As it turned more to the southwest, the depression weakened until it dissipated on August 13 about 600 miles (970 km) south-southeast of Hilo, Hawaii.[38]

Tropical Depression Twelve-E

Tropical depression (SSHWS)
 
DurationAugust 17 – August 19
Peak intensity35 mph (55 km/h) (1-min);

A persistent area of thunderstorm activity southwest of Puerto Vallarta became better organized and strengthened into Tropical Depression 12-E on August 17. Moving northwest, the system developed slowly as it was embedded within the Intertropical Convergence Zone. Easterly shear kept the system from reaching tropical storm strength and caused its ultimate dissipation on August 19. No damages or fatalities were caused by this depression.[39]

Hurricane Julio

Category 3 hurricane (SSHWS)
 
DurationAugust 17 – August 24
Peak intensity115 mph (185 km/h) (1-min);
960 mbar (hPa)

A tropical wave moved off the western coast of Africa on August 5, moving across the Atlantic Ocean and Caribbean Sea without significant development.[40] The system entered the northeastern Pacific Ocean, and became well-enough organized to be upgraded to Tropical Depression Thirteen-E on August 17 while centered 350 nautical miles (650 km) south of Acapulco, Mexico. The depression moved on a west-northwestward track and strengthened, becoming Tropical Storm Julio on August 18. Strengthening continued and Julio reached hurricane strength on August 19. The cyclone peaked with maximum sustained winds of 115 miles per hour (185 km/h) on August 21. The storm turned westward and began weakening. Julio regained tropical storm status on August 23 and tropical depression status on August 24 before dissipating as a tropical cyclone later that day. No damage was reported from Julio.[40]

Hurricane Kenna

Category 1 hurricane (SSHWS)
 
DurationAugust 21 – August 30
Peak intensity85 mph (140 km/h) (1-min);
980 mbar (hPa)

A tropical wave moved off the coast of Africa on August 9. This wave spawned Tropical Storm Fran on August 13, before it moved through the southern Windward Islands on August 14. While Fran dissipated shortly after that, the tropical wave progressed into the northeastern Pacific Ocean.[41]

The wave spawned Tropical Depression Fourteen-E 700 nautical miles (1,300 km) east-southeast of Hurricane Julio. The depression moved westward for the next several days. As Julio weakened, the depression began to increase in strength. It became Tropical Storm Kenna on August 22 and continued to strengthen into a hurricane on August 25, peaking with winds of 85 miles per hour (137 km/h) the next day. On August 26, a strong frontal trough weakened the high pressure system to the storm's north, causing a turn to the north during the next few days. The hurricane weakened in response to cooler water and increasing vertical wind shear, which removed convection from its center. Kenna weakened back to tropical storm strength on August 28, then into a tropical depression on August 29. The system dissipated as a tropical cyclone on August 30.[41][42][43]

Hurricane Lowell

Category 1 hurricane (SSHWS)
 
DurationAugust 23 – September 1
Peak intensity75 mph (120 km/h) (1-min);
986 mbar (hPa)

A tropical wave moved off the northwestern coast of Africa into the Atlantic Ocean on August 11. After moving across the Atlantic and Caribbean Sea without development, the system moved through the Intertropical Convergence Zone of the northeastern Pacific Ocean.[44] The cloudiness moved northward toward the Gulf of Tehuantepec on August 22. The thunderstorm activity organized sufficiently for the system to be upgraded to Tropical Depression Fifteen-E on August 23 while 260 nautical miles (480 km) southeast of Acapulco, Mexico. The depression moved west-northwestward and strengthened into a tropical storm 190 nautical miles (350 km) south-southwest of Puerto Vallarta on August 25. The storm began to turn more westward due to a strengthening high pressure system to its north and was upgraded to a hurricane on August 27 while 250 nautical miles (460 km) southwest of Cabo San Lucas. As the high to the north continued to strengthen, the hurricane turned west-southwest.[44]

Thunderstorm activity with the hurricane began to weaken and Lowell was downgraded back to tropical storm status on August 28. The tropical storm then turned to a north-northwestward with the storm passing over cooler waters. On August 31, the storm was downgraded to a tropical depression, with only minimal amounts of deep convection remaining within its circulation. Lowell dissipated as a tropical cyclone on September 1, though a low-level circulation of clouds could be seen on satellite imagery for the next few days. No damage or casualties was reported as a result of Lowell.[44][45]

Hurricane Marie

Category 4 hurricane (SSHWS)
 
DurationSeptember 7 – September 21
Peak intensity140 mph (220 km/h) (1-min);
944 mbar (hPa)

A tropical wave moved off the northwestern coast of Africa on August 16. The wave moved west through the Atlantic Ocean and Caribbean sea without significant development.[46] The wave moved across Central America and into the northeastern Pacific Ocean, on August 29. Isolated convection with the system increased while south of the Gulf of Tehuantepec as the system moved northwest parallel to the southwest coast of Mexico. Once convective activity increased, the system was upgraded to Tropical Depression Sixteen-E on September 7 while centered 570 nautical miles (1,060 km) southwest of Clarion Island.[46]

A weaker than normal high pressure system controlled the movement of the depression, and the system moved slowly to the west through its lifetme. The depression strengthened into Tropical Storm Marie on September 8, and into a hurricane on September 9, while 840 nautical miles (1,560 km) south-southwest of Clarion Island. Marie reached its peak intensity of 140 miles per hour (230 km/h) on September 11.[46] The hurricane crossed into the central North Pacific on September 14 as a hurricane with maximum sustained winds of 110 miles per hour (180 km/h). The hurricane weakened thereafter and on September 17 Marie regained tropical storm status. The system weakened into a tropical depression on September 19 and dissipated as a tropical cyclone on September 21 near the Hawaiian coast. No casualties or damages were caused by Marie.[47]

Hurricane Norbert

Category 1 hurricane (SSHWS)
 
DurationSeptember 10 – September 19
Peak intensity80 mph (130 km/h) (1-min);
983 mbar (hPa)

A tropical wave moved off the coast of Africa and across the Atlantic Ocean and Caribbean Sea without significant development. The wave entered the northeastern Pacific Ocean and began to show signs of organized thunderstorm development.[48] Tropical Depression Seventeen-E formed on September 10 while centered 660 nautical miles (1,220 km) south-southwest of Cabo San Lucas, Mexico. The depression became better organized and strengthened into Tropical Storm Norbert later in the day.

On September 12, Norbert absorbed Tropical Depression Eighteen-E which was in close proximity. Norbert strengthened as it moved north-northwestward. The tropical storm was upgraded to a hurricane on September 14, and formed an eye on September 15. The storm reached its peak strength of 80 miles per hour (130 km/h) sustained winds that day. Turning north of due west,[48] Norbert then weakened as it moved over cooler waters. It was downgraded to a tropical storm later on September 15, and then to a tropical depression on September 18. Norbert dissipated as a tropical cyclone on September 19 after losing all its deep convection.[48][49]

Tropical Depression Eighteen-E

Tropical depression (SSHWS)
 
DurationSeptember 11 – September 12
Peak intensity35 mph (55 km/h) (1-min);

On September 11, a tropical depression formed southwest of Cabo San Lucas very near of Norbert, which hindered the development of this depression. Later that day, it was forecast that this depression would absorb Norbert. However, Norbert absorbed this tropical depression instead.[50]

Hurricane Odile

Category 4 hurricane (SSHWS)
 
DurationSeptember 23 – October 2
Peak intensity145 mph (230 km/h) (1-min);
935 mbar (hPa)

A tropical wave move off the coast of Africa on September 5, and crossed the Atlantic waters, the Caribbean Sea and eventually into the Pacific Ocean as a weak system.[51] An area of convection entered into the northeastern Pacific Ocean a few hundred miles south of Acapulco, Mexico. On September 2, Tropical Depression Nineteen-E formed from this convection, while 650 nautical miles (1,200 km) south-southeast from the southern tip of Baja California. The depression moved on a west-northwestward track, rounding the southwest side of a strong high pressure system. The depression continued to strengthen and was upgraded to Tropical Storm Odile on September 24 and into a hurricane on September 25. Its intensity peaked with maximum sustained winds of 145 miles per hour (233 km/h) on September 26.[51]

The hurricane began to turn more northwestward in response to a high-pressure system weakening to its north. Odile began to weaken as it moved over cooler waters on September 28. The cyclone regained tropical storm status on September 29 while it slowly progressed northward. The system weakened into a tropical depression status on September 30. Once it lost its deep convection, Odile was steered southwestward by the low-level flow, before it dissipated as a tropical cyclone on October 2. Its remaining low-level circulation of clouds continued on a southwestward course thereafter.[51][52]

Hurricane Polo

Category 1 hurricane (SSHWS)
DurationSeptember 28 – October 1
Peak intensity75 mph (120 km/h) (1-min);
987 mbar (hPa)

Polo originated from a tropical wave that moved off the African coast on September 2 which spawned Tropical Storm Isidore in the Atlantic basin. On September 14, the system increased in convection as it was moving to the west and approaching Central America. The southern extent of the wave crossed into the Pacific Ocean on September 18.[53]

The wave continued westward and related thunderstorm activity increased during the following week. The convective system organized into Tropical Depression Twenty-E on September 28 nearly midway between Mexico and Hawaii. Initially, the depression drifted toward the northwest due to a large upper-level trough located to its west. Polo strengthened rapidly into a hurricane early on September 30, with its winds peaking at 75 miles per hour (121 km/h). Since the storm was very small, vertical wind shear caused significant weakening thereafter. On October 1, Polo regained tropical storm strength as it was crossing into the north Central Pacific basin. It dissipated as a tropical cyclone later that day.[53] There were no casualties or damages caused by Polo.[54]

Tropical Storm Rachel

Tropical storm (SSHWS)
 
DurationSeptember 27 – October 3
Peak intensity65 mph (100 km/h) (1-min);
994 mbar (hPa)

In mid-September, a weak tropical wave moved off the coast of Northwest Africa. It moved westward and entered the eastern Pacific Ocean early on September 23. Cloudiness became concentrated with the system south of the Gulf of Tehuantepec. On September 27, the organized thunderstorm area was upgraded to Tropical Depression Twenty One-E while 200 nautical miles (370 km) south of Acapulco, Mexico. The depression developed slowly, and became a tropical storm on September 30 500 nautical miles (930 km) south of Cabo San Lucas, Mexico. As Rachel moved northwest, a low over California steered it on a more northerly course. Rachel recurved and accelerated with a quickening forward speed towards the Mexican coast. The storm passed over the southern portion of Baja California on October 2. Rachel's center of circulation made its final landfall midway between Los Mochis and Culiacán, and became the only system to make landfall from the eastern north Pacific ocean in 1990.[55][56][57] In Mexico, Baja Calfornia Sur, Sinaloa, and Chihuahua states were impacted by Rachel.[58]

Rachel decayed rapidly over land, and its remnants continued accelerating over Texas until they lost their identity. The last public advisory on the depression was issued on October 2 as the system dissipated as a tropical cyclone. The highest rainfall total from the system in Mexico totaled 9.85 inches (250 mm) at Santa Anita/Los Cabos near the tip of Baja California.[59] No reports of damage or casualties were received from Mexico. In Texas, Rachel's remnants caused heavy rain. Flooding occurred in the Big Bend area.[55][56][57][60]

Tropical Storm Simon

Tropical storm (SSHWS)
 
DurationOctober 9 – October 14
Peak intensity70 mph (110 km/h) (1-min);
990 mbar (hPa)

A weakly defined tropical wave moved off the northwest coast of Africa on September 20, and crossed the northern portion of the tropical Atlantic and northern South America without significant organization.[61] The wave moved into the northeastern Pacific waters, off the coast of Colombia on September 30. As the wave passed over southern Central America, rainbands and cloudiness increased with the system between October 1 and October 3, before the system merged with the Intertropical Convergence Zone from October 4 to October 6. Signs of convective organization reappeared on October 8, and by October 9, the system was upgraded to Tropical Depression Twenty Two-E 500 nautical miles (930 km) south of Cabo San Lucas, Mexico.

The depression continued to develop and was upgraded to Tropical Storm Simon on October 10 while 525 nautical miles (972 km) south-southwest of Cabo San Lucas. Due to a high-pressure system to the north-northwest, Simon continued on a west-northwestward path. The tropical storm continued to strengthen to its peak intensity of 70 miles per hour (110 km/h) by late on October 11.[61] Simon passed over cooler waters and weakened back into a tropical depression on October 13. The depression moved on a westward course, and the low-level circulation was displaced from its deep convection during the following day. Simon then dissipated as a tropical cyclone early on October 15 across the open waters of the northeast Pacific.[61]

Hurricane Trudy

Category 4 hurricane (SSHWS)
 
DurationOctober 16 – November 1
Peak intensity155 mph (250 km/h) (1-min);
924 mbar (hPa)

A tropical wave moved across the northeast Pacific ocean and formed a tropical depression south of Mexico on October 16. It strengthened at a moderate pace and reached hurricane intensity on October 18. Trudy entered a favorable environment and explosively intensified, reaching its first peak in strength on October 20. At that time, an upper-level trough drifted Trudy north. and increased vertical shear, which substantially weakened the system back to tropical storm strength. The trough outran the storm and was replaced by a ridge which turned the storm back to the west and led to its re-intensification to a Category 4 hurricane. Another upper level trough approached which pulled Trudy northward once again, and sheared the hurricane apart. The cyclone dissipated on November 1. Eventually, some of its moisture spread over parts of Mexico and the United States.[62]

Except for Socorro Island, Trudy had no impact on land. The island reported hurricane force winds for seven hours.[62] Trudy also had an unusually large eye, which was as large as 50 nautical miles (93 km) wide.[63] Trudy is the ninth-strongest Pacific hurricane overall and the second strongest October storm, behind Kenna of the 2002 season.[1]

Hurricane Vance

Category 2 hurricane (SSHWS)
 
DurationOctober 21 – October 31
Peak intensity100 mph (155 km/h) (1-min);
975 mbar (hPa)

An area of disturbed weather, possibly related to a tropical wave, organized into Tropical Depression Twenty Four-E on October 21. It strengthened into Tropical Storm Vance early on October 23 and then into a hurricane two days later. Vance moved parallel to the west coast of Mexico and approached the southern tip of the Baja California Peninsula. Before it could strike land, a high-pressure area blocked Vance's path and forced the storm to transcribe a small clockwise loop over a two-day period. During the loop, Vance encountered wind shear and cool waters stirred up by Trudy as well as earlier in Vance's life cycle. Vance weakened to a tropical storm on October 27 and a depression on October 30. The cyclone dissipated late on October 31.[64] The formation of Vance, the season's 20th tropical storm, made 1990 the busiest season since 1985.[1]

Accumulated Cyclone Energy (ACE) Rating

ACE (104 kt2) – Storm
1 44.75 Trudy 12 6.57 Lowell
2 33.08 Marie 13 5.30 Elida
3 30.57 Hernan 14 5.12 Boris
4 21.9 Iselle 15 (4.93) Aka
5 18.36 Odile 16 4.61 Alma
6 12.65 Julio 17 3.78 Cristina
7 11.68 Genevieve 18 3.67 Simon
8 10.37 Vance 19 3.36 Douglas
9   9.72 Kenna 20 2.51 Rachel
10   7.97 Norbert 21 1.96 Polo
11   6.59 Fausto
Total= 245.52 (4.93)

The table on the right shows the ACE for each storm in the season. ACE is, broadly speaking, a measure of the power of the hurricane multiplied by the length of time it existed, so storms that last a long time, as well as particularly strong hurricanes, have high ACEs. ACE is only calculated for full advisories on tropical systems at or exceeding 34 knots (39 mph, 63 km/h) or tropical storm strength.

The figures in parentheses are for storms in the Central Pacific basin west of 140°W; those not in parenthesis are for the Eastern Pacific basin.

The cumulative ACE for the Eastern Pacific this season fell within the official "Above Normal" grading, being one of the most active. This occurred because the season had many intense storms that lasted for a long period of time. Also it is important to note that this is the second highest ACE, only behind the 1992 Pacific hurricane season.[1]

1990 storm names

The following names were used for named storms that formed in the eastern Pacific in 1990. No names were retired, so it was used again in the 1996 season. This is the same list used for the 1984 season. Storms were named Trudy and Vance for the first time in 1990. Names that were not assigned are marked in gray.

  • Alma
  • Boris
  • Cristina
  • Douglas
  • Elida
  • Fausto
  • Genevieve
  • Hernan
  • Iselle
  • Julio
  • Kenna
  • Lowell
  • Marie
  • Norbert
  • Odile
  • Polo
  • Rachel
  • Simon
  • Trudy
  • Vance
  • Winnie (unused)
  • Xavier (unused)
  • Yolanda (unused)
  • Zeke (unused)

One name from the Central Pacific list was used - Aka. It was the first usage for that name.

See also

Template:Tcportal

References

  1. ^ a b c d e f g h National Hurricane Center (2010). "Eastern Pacific Hurricane Database". Atlantic Oceanographic and Meteorological Laboratory. Retrieved 2010-04-26.
  2. ^ a b Lixion Avila (1990). "Eastern North Pacific Season of 1990" (PDF). Monthly Weather Review. National Hurricane Center. Retrieved 2006-12-20.
  3. ^ a b c Robert A. Case (1990). "Hurricane Alma Prelim 1". National Hurricane Center. Retrieved 2006-12-01.
  4. ^ Max Mayfield (1990). "Tropical Cyclone Discussion Tropical Depression One-E". National Hurricane Center. Retrieved 2007-11-24.
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  8. ^ a b c Max Mayfield (1990). "Hurricane Boris Prelim 1". National Hurricane Center. Retrieved 2006-12-01.
  9. ^ a b Max Mayfield (1990). "Hurricane Boris Prelim 2". National Hurricane Center. Retrieved 2006-12-01.
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  13. ^ a b Lixion Avalia (1990). "Tropical Storm Cristina Prelim 1". National Hurricane Center. Retrieved 2006-12-01.
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Template:1990-1999 Pacific hurricane seasons