1990 Pacific hurricane season
Encyclopedia
The 1990 Pacific hurricane season is the fifth most active season on record. 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.
Hurricane Alma became the third earliest tropical cyclone in the Eastern Pacific basin since the satellite era began in 1966, while Trudy is the third strongest October eastern Pacific hurricane on record. Overall, the impact of this season was minimal. Tropical Storm Rachel made two landfalls in Mexico
and brought rain to the United States
. Hurricane Boris brought light showers to California
.
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
. All of the tropical cyclones of this year developed from westward-moving Africa
n tropical wave
s. The season established several tropical storm records for this basin and was marked by several strong hurricanes. There were 21 named tropical cyclones, seven 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.
With the exception of Marie and Polo, these systems developed between 5°
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. In addition, one tropical storm formed in the Central Pacific and eventually crossed the International Dateline before dissipating.
, 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.
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. Alma became the earliest named storm and hurricane in the satellite
era in the east Pacific proper.
limited the amount of the initial strengthening. However, an increase in convective banding led to its upgrade to Tropical Storm Boris on June 4, 500 mi (804.7 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 mph (144.8 km/h) and a minimum central pressure of 977 mb. 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.
The winds in the eyewall of Boris ripped off the sails of the Azure Dream sailboat. Outer rainbands from the storm produced moderate rain in several Mexican states. In Mexico, rainfall peaked at 8.83 in (224.3 mm) near San Lucas, Michoacán
. The remnants of Boris also brought sporadic rainfall over the western United States, with precipitation being reported in Arizona
, California
, Colorado
, Nevada
and Wyoming
. The remnants of Boris were responsible for causing the wettest June in San Diego
since records began in 1850, however, not even 1 in (25.4 mm) of rain fell at that location. Rainfall from the remnant system in the United States peaked at 3.28 in (83.3 mm) over the Santa Rita Mountains
. No other direct damages or casualties were reported from Boris.
Cristina initially had well-established upper-level outflow
. It failed to reach hurricane status, peaking with maximum sustained wind
s of 65 mph (104.6 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. 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.
, 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 230 mi (370.1 km) southwest of Acapulco. Douglas reached peak strength of 65 mph (104.6 km/h) on June 21
A tropical storm warning was issued on June 21, from Punta Tejupan to Cabo Corrientes
before being discontinued on June 22. Tropical Storm Douglas brushed the western coast of Mexico. The center of circulation approached within 17 mi (27.4 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 138 mi (222.1 km) south-southeast of the southern tip of Baja California
. The highest rainfall report from Mexico from Douglas totaled 11.07 in (281.2 mm) at La Huerta. No deaths or damage were reported.
turning in the lower and middle layers of the system's cloudiness on June 25. The center of circulation was located 345 mi (555.2 km) south of Acapulco, Mexico. The system exhibited sufficient organization to be considered Tropical Depression Five-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 rainband
s 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 mph (128.7 km/h), dropping 3.7 in (94 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.
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.
(ITCZ), the National Hurricane Center discontinued advisories on Tropical Depression Six-E, stating that the depression dissipated, and regeneration seemed unlikely.
However, wind shear began to decrease, and convection associated with the remnants of Tropical Depression Six-E quickly began to increase. Although the low-level circulation was near the edge of the deep convection, the National Hurricane Center resumed advisories on Tropical Depression Six-E by July 1. Intensification into a tropical storm was again predicted, but Tropical Depression Six-E remained poorly-defined, and eventually dissipated on July 4.
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, 265 mi (426.5 km) south of Manzanillo
, Mexico. A weakly defined eye formed on July 8, and the storm was upgraded to Hurricane Fausto, 310 mi (498.9 km) south of Cabo San Lucas.
Fausto peaked in strength with winds of 85 mph (140 km/h) and a central pressure of 979 mb on July 9. Fausto passed 40 mi (60 km) north of Socorro Island causing a northwest wind of 40 mph (60 km/h), and 4.3 in (109.2 mm) of rain at that location. The hurricane fluctuated in intensity on July 10, before weakening into a tropical storm later that day, 403 mi (648.6 km) west of Cabo San Lucas. The weakening Fausto moved over continuing cooler waters, and was downgraded to a tropical depression on June 11, 690 mi (1,110.4 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.
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 mph (170 km/h) with a well-defined eye at its center of circulation. 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.
Tropical Depression Nine-E strengthened into Tropical Storm Hernan on July 21 while 684 mi (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 145 mi (230 km) southwest of Clarion Island
. On July 23, Hernan reached its peak strength of 155 mph (250 km/h) and minimum pressure of 928 mb as the center of circulation was 207 mi (335 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.
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.
, Mexico. 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.
The hurricane continued to move west-northwest through its duration, and reached its peak strength of 120 mph (193.1 km/h) on July 25. Iselle crossed Socorro Island, which recorded a 70 mi/h sustained wind and heavy rain on July 25. 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 588 mi (946.3 km) southwest of San Diego.
. On August 10, Tropical Storm Aka peaked with maximum sustained winds of 60 mph (96.6 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. Aka weakened back into a depression and dissipated two days later on August 15.
while developing significant convection before it moved into northwest Mexico, which brought rainfall amounts of over 10 in (254 mm) to local areas within the state of Sonora
. The remnant disturbance moved into the American Southwest on August 11.
, 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 mi (965.6 km) south-southeast of Hilo, Hawaii.
became better organized and strengthened into Tropical Depression Twelve-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.
on August 14. While Fran dissipated shortly after that, the tropical wave progressed into the northeastern Pacific Ocean. The wave spawned Tropical Depression Fourteen-E 808 mi (1,300.3 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 mph (136.8 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.
on August 22. The thunderstorm activity organized sufficiently for the system to be upgraded to Tropical Depression Fifteen-E on August 23 while 298 mi (479.6 km) southeast of Acapulco, Mexico. The depression moved west-northwestward and strengthened into a tropical storm 217 mi (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 286 mi (460.3 km) southwest of Cabo San Lucas. As the high to the north continued to strengthen, the hurricane turned west-southwest.
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.
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 522 mi (840.1 km) south-southwest of Clarion Island. Marie reached its peak intensity of 140 mph (225.3 km/h) on September 11. The hurricane crossed into the central North Pacific on September 14 as a hurricane with maximum sustained winds of 110 mph (177 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.
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 mph (128.7 km/h) sustained winds that day. Turning north of due west, 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.
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.
. 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.
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 mph (120.7 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. There were no casualties or damages caused by Polo.
. On September 27, the organized thunderstorm area was upgraded to Tropical Depression Twenty One-E while 230 mi (370.1 km) south of Acapulco
. The depression developed slowly, and became a tropical storm on September 30. As Rachel briefly moved northward, before re-curving and accelerating towards the Mexican coast. The storm passed over the southern portion of Baja California Sur
on October 2. Rachel 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. Rachel decayed rapidly over land, and the final public advisory on Rachel was issued early on October 3. its remnants continued accelerating over Texas until they lost their identity.
The highest rainfall total from the system in Mexico
totaled 9.85 in (250.2 mm) at Santa Anita near the tip of Baja California. Across norther, Mexico, thousands were homeless, and 18 people died. In Texas
, Rachel's remnants caused heavy rain. Flooding occurred in the Big Bend area.
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 ITCZ 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 578 mi (930.2 km) south of Cabo San Lucas, Mexico.
The depression continued to develop and was upgraded to Tropical Storm Simon on October 10 while 604 mi (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 mph (112.7 km/h) by late on October 11. 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.
Except for Socorro Island, Trudy had no impact on land. The island reported hurricane force winds for seven hours. Trudy also had an unusually large eye, which was as large as 58 mi (93.3 km) wide. Trudy is the third-strongest Pacific hurricane in October, behind Kenna
of the 2002 season and Rick
of the 2009 season.
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
.
. 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.
One name from the Central Pacific list was used - Aka. It was the first usage for that name.
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
. However, these bounds were slightly exceeded when Hurricane Alma formed on May 12.
Hurricane Alma became the third earliest tropical cyclone in the Eastern Pacific basin since the satellite era began in 1966, while Trudy is the third strongest October eastern Pacific hurricane on record. Overall, the impact of this season was minimal. Tropical Storm Rachel made two landfalls in Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
and brought rain to the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. Hurricane Boris brought light showers to California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
.
Season summary
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
was active in terms of number of storms that attained at least tropical storm intensity and of Accumulated Cyclone Energy
Accumulated cyclone energy
Accumulated cyclone energy is a measure used by the National Oceanic and Atmospheric Administration to express the activity of individual tropical cyclones and entire tropical cyclone seasons, particularly the North Atlantic hurricane season. It uses an approximation of the energy used by a...
. All of the tropical cyclones of this year developed from westward-moving Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
n tropical wave
Tropical wave
Tropical waves, easterly waves, or tropical easterly waves, also known as African easterly waves in the Atlantic region, are a type of atmospheric trough, an elongated area of relatively low air pressure, oriented north to south, which move from east to west across the tropics causing areas of...
s. The season established several tropical storm records for this basin and was marked by several strong hurricanes. There were 21 named tropical cyclones, seven 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
Saffir-Simpson Hurricane Scale
The Saffir–Simpson Hurricane Scale , or the Saffir–Simpson Hurricane Wind Scale , classifies hurricanes — Western Hemisphere tropical cyclones that exceed the intensities of tropical depressions and tropical storms — into five categories distinguished by the intensities of their sustained winds...
. Hurricanes Hernan and Trudy were among the strongest ever observed in this area. Alma became the earliest named tropical cyclone for the eastern Pacific
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
ocean east of the 140th meridian west
140th meridian west
The meridian 140° west of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, North America, the Pacific Ocean, the Southern Ocean, and Antarctica to the South Pole....
. The eastern Pacific produced four tropical depressions that did not reach tropical storm status.
With the exception of Marie and Polo, these systems developed between 5°
5th parallel north
The 5th parallel north is a circle of latitude that is 5 degrees north of the Earth's equatorial plane. It crosses the Atlantic Ocean, Africa, the Indian Ocean, Southeast Asia, the Pacific Ocean and South America....
and 15°N
15th parallel north
The 15th parallel north is a circle of latitude that is 15 degrees north of the Earth's equatorial plane. It crosses Africa, Asia, the Indian Ocean, the Pacific Ocean, Central America, the Caribbean and the Atlantic Ocean....
, east of the longitude of Baja California
Baja California
Baja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...
in the climatologically
Climate
Climate encompasses the statistics of temperature, humidity, atmospheric pressure, wind, rainfall, atmospheric particle count and other meteorological elemental measurements in a given region over long periods...
favored area for tropical cyclogenesis
Tropical cyclogenesis
Tropical cyclogenesis is the term that describes the development and strengthening of a tropical cyclone in the atmosphere. The mechanisms through which tropical cyclogenesis occurs are distinctly different from those through which mid-latitude cyclogenesis occurs...
. 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. In addition, one tropical storm formed in the Central Pacific and eventually crossed the International Dateline before dissipating.
Hurricane Alma
A tropical wave emerged from Africa on April 29. It then moved across the Atlantic, crossed northern South AmericaSouth America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
, and entered the Pacific Ocean on May 9. Convection
Convection
Convection is the movement of molecules within fluids and rheids. It cannot take place in solids, since neither bulk current flows nor significant diffusion can take place in solids....
started to increase with the wave just to the south of Panama
Panama
Panama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...
. 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.
Tropical Depression One-E moved slowly to the northwest while strengthening slowly due to easterly vertical wind shear
Wind shear
Wind shear, sometimes referred to as windshear or wind gradient, is a difference in wind speed and direction over a relatively short distance in the atmosphere...
. 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
Ridge
A ridge is a geological feature consisting of a chain of mountains or hills that form a continuous elevated crest for some distance. Ridges are usually termed hills or mountains as well, depending on size. There are several main types of ridges:...
of high pressure
High pressure
High pressure in science and engineering is studying the effects of high pressure on materials and the design and construction of devices, such as a diamond anvil cell, which can create high pressure...
. The increasing vertical wind shear and cooler water
Sea surface temperature
Sea surface temperature is the water temperature close to the oceans surface. The exact meaning of surface varies according to the measurement method used, but it is between and below the sea surface. Air masses in the Earth's atmosphere are highly modified by sea surface temperatures within a...
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. Alma became the earliest named storm and hurricane in the satellite
Weather satellite
The weather satellite is a type of satellite that is primarily used to monitor the weather and climate of the Earth. Satellites can be either polar orbiting, seeing the same swath of the Earth every 12 hours, or geostationary, hovering over the same spot on Earth by orbiting over the equator while...
era in the east Pacific proper.
Hurricane Boris
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. 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 shearWind shear
Wind shear, sometimes referred to as windshear or wind gradient, is a difference in wind speed and direction over a relatively short distance in the atmosphere...
limited the amount of the initial strengthening. However, an increase in convective banding led to its upgrade to Tropical Storm Boris on June 4, 500 mi (804.7 km) southwest of Manzanillo. An anticyclone
Anticyclone
An anticyclone is a weather phenomenon defined by the United States' National Weather Service's glossary as "[a] large-scale circulation of winds around a central region of high atmospheric pressure, clockwise in the Northern Hemisphere, counterclockwise in the Southern Hemisphere"...
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
West Coast of the United States
West Coast or Pacific Coast are terms for the westernmost coastal states of the United States. The term most often refers to the states of California, Oregon, and Washington. Although not part of the contiguous United States, Alaska and Hawaii do border the Pacific Ocean but can't be included in...
. Strengthening continued, and the storm reached its peak strength with winds of 90 mph (144.8 km/h) and a minimum central pressure of 977 mb. 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.
The winds in the eyewall of Boris ripped off the sails of the Azure Dream sailboat. Outer rainbands from the storm produced moderate rain in several Mexican states. In Mexico, rainfall peaked at 8.83 in (224.3 mm) near San Lucas, Michoacán
San Lucas, Michoacán
San Lucas is a municipality located in the Mexican state of Michoacán. The municipality has an area of 474.41 square kilometres and is bordered to the north by the municipality of Tiquicheo, to the east and south by the state of Guerrero, and to the west by Huetamo. The municipality had a...
. The remnants of Boris also brought sporadic rainfall over the western United States, with precipitation being reported in Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...
, California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...
, Nevada
Nevada
Nevada is a state in the western, mountain west, and southwestern regions of the United States. With an area of and a population of about 2.7 million, it is the 7th-largest and 35th-most populous state. Over two-thirds of Nevada's people live in the Las Vegas metropolitan area, which contains its...
and Wyoming
Wyoming
Wyoming is a state in the mountain region of the Western United States. The western two thirds of the state is covered mostly with the mountain ranges and rangelands in the foothills of the Eastern Rocky Mountains, while the eastern third of the state is high elevation prairie known as the High...
. The remnants of Boris were responsible for causing the wettest June in San Diego
San Diego, California
San Diego is the eighth-largest city in the United States and second-largest city in California. The city is located on the coast of the Pacific Ocean in Southern California, immediately adjacent to the Mexican border. The birthplace of California, San Diego is known for its mild year-round...
since records began in 1850, however, not even 1 in (25.4 mm) of rain fell at that location. Rainfall from the remnant system in the United States peaked at 3.28 in (83.3 mm) over the Santa Rita Mountains
Santa Rita Mountains
The Santa Rita Mountains, located about 65 km southeast of Tucson, Arizona, extend 42 km from north to south, then trending southeast. They merge again southeastwards into the Patagonia Mountains, trending northwest by southeast...
. No other direct damages or casualties were reported from Boris.
Tropical Storm Cristina
A tropical wave emerged into the Atlantic Ocean off the coast of Africa on May 28. 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 Three-E on June 8, while 920 mi (1,480.6 km) south of the southern tip of Baja California. The depression continued to strengthen, and was upgraded to Tropical Storm Cristina on June 9.Cristina initially had well-established upper-level outflow
Outflow (meteorology)
Outflow, in meteorology, is air that flows outwards from a storm system. It is associated with ridging, or anticyclonic flow. In the low levels of the troposphere, outflow radiates from thunderstorms in the form of a wedge of rain-cooled air, which is visible as a thin rope-like cloud on weather...
. It failed to reach hurricane status, peaking with maximum sustained wind
Maximum sustained wind
The maximum sustained winds associated with a tropical cyclone are a common indicator of the intensity of the storm. Within a mature tropical cyclone, they are found within the eyewall at a distance defined as the radius of maximum wind, or RMW. Unlike gusts, the value of these winds are...
s of 65 mph (104.6 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. 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.
Tropical Storm Douglas
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. 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 230 mi (370.1 km) south of AcapulcoAcapulco
Acapulco is a city, municipality and major sea port in the state of Guerrero on the Pacific coast of Mexico, southwest from Mexico City. Acapulco is located on a deep, semi-circular bay and has been a port since the early colonial period of Mexico’s history...
, 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
Subtropical ridge
The subtropical ridge is a significant belt of high pressure situated around the latitudes of 30°N in the Northern Hemisphere and 30°S in the Southern Hemisphere. It is characterized by mostly calm winds, which acts to reduce air quality under its axis by causing fog overnight, and haze during...
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 230 mi (370.1 km) southwest of Acapulco. Douglas reached peak strength of 65 mph (104.6 km/h) on June 21
A tropical storm warning was issued on June 21, from Punta Tejupan to Cabo Corrientes
Cabo Corrientes
Cabo Corrientes is a cape on the Pacific coast of the Mexican state of Jalisco. It marks the southernmost point of the Bahía de Banderas, upon which the port and resort city of Puerto Vallarta stands. The municipality in which the cape lies is also called Cabo Corrientes.Cabo Corrientes is a...
before being discontinued on June 22. Tropical Storm Douglas brushed the western coast of Mexico. The center of circulation approached within 17 mi (27.4 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 138 mi (222.1 km) south-southeast of the southern tip of Baja California
Baja California
Baja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...
. The highest rainfall report from Mexico from Douglas totaled 11.07 in (281.2 mm) at La Huerta. No deaths or damage were reported.
Hurricane Elida
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. The wave became a significant tropical system, with cyclonicCyclone
In meteorology, a cyclone is an area of closed, circular fluid motion rotating in the same direction as the Earth. This is usually characterized by inward spiraling winds that rotate anticlockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere of the Earth. Most large-scale...
turning in the lower and middle layers of the system's cloudiness on June 25. The center of circulation was located 345 mi (555.2 km) south of Acapulco, Mexico. The system exhibited sufficient organization to be considered Tropical Depression Five-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 rainband
Rainband
A rainband is a cloud and precipitation structure associated with an area of rainfall which is significantly elongated. Rainbands can be stratiform or convective, and are generated by differences in temperature. When noted on weather radar imagery, this precipitation elongation is referred to as...
s 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
Socorro Island
Socorro Island is a small volcanic island in the Revillagigedo Islands, a Mexican possession lying some 600 kilometers off the country's western coast at 18°48'N, 110°59'W. The size is 16.5 by 11.5 km, with an area of 132 km².- Geology :...
later in the day, right as Elida reached peak strength of 80 mph (128.7 km/h), dropping 3.7 in (94 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.
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.
Tropical Depression Six-E
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 and near hurricane intensity by late on July 2 or early on July 3, however persistent vertical wind shear over the system impeded its development. After convection began to merge into the Intertropical Convergence ZoneIntertropical Convergence Zone
The Intertropical Convergence Zone , known by sailors as The Doldrums, is the area encircling the earth near the equator where winds originating in the northern and southern hemispheres come together....
(ITCZ), the National Hurricane Center discontinued advisories on Tropical Depression Six-E, stating that the depression dissipated, and regeneration seemed unlikely.
However, wind shear began to decrease, and convection associated with the remnants of Tropical Depression Six-E quickly began to increase. Although the low-level circulation was near the edge of the deep convection, the National Hurricane Center resumed advisories on Tropical Depression Six-E by July 1. Intensification into a tropical storm was again predicted, but Tropical Depression Six-E remained poorly-defined, and eventually dissipated on July 4.
Hurricane Fausto
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. An area of disturbed weather moved northwards towards the Gulf of TehuantepecGulf of Tehuantepec
Gulf of Tehuantepec is a large body of water on the Pacific coast of the Isthmus of Tehuantepec, southeastern Mexico, at . Most of the hurricanes that form in the Eastern Pacific organize in or near this body of water...
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, 265 mi (426.5 km) south of Manzanillo
Manzanillo, Colima
The name Manzanillo refers to the city as well as its surrounding municipality in the Mexican state of Colima. The city, located on the Pacific Ocean, contains Mexico's busiest port. Manzanillo was the third port created by the Spanish in the Pacific during the New Spain period...
, Mexico. A weakly defined eye formed on July 8, and the storm was upgraded to Hurricane Fausto, 310 mi (498.9 km) south of Cabo San Lucas.
Fausto peaked in strength with winds of 85 mph (140 km/h) and a central pressure of 979 mb on July 9. Fausto passed 40 mi (60 km) north of Socorro Island causing a northwest wind of 40 mph (60 km/h), and 4.3 in (109.2 mm) of rain at that location. The hurricane fluctuated in intensity on July 10, before weakening into a tropical storm later that day, 403 mi (648.6 km) west of Cabo San Lucas. The weakening Fausto moved over continuing cooler waters, and was downgraded to a tropical depression on June 11, 690 mi (1,110.4 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.
Hurricane Genevieve
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. The system became better organized as it moved into the northeastern Pacific Ocean. The system was upgraded to Tropical Depression Eight-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 23 mi (37 km) of Socorro Island where a sustained wind of 44 mph (70.8 km/h) and gust of 50 mph (80.5 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 mph (170 km/h) with a well-defined eye at its center of circulation. 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
Stratocumulus cloud
A Stratocumulus cloud belongs to a class of clouds characterized by large dark, rounded masses, usually in groups, lines, or waves, the individual elements being larger than those in altocumuli, and the whole being at a lower altitude, usually below 2,400 m...
field.
Hurricane Hernan
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. 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 565 mi (910 km) southwest of Acapulco, Mexico.Tropical Depression Nine-E strengthened into Tropical Storm Hernan on July 21 while 684 mi (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 145 mi (230 km) southwest of Clarion Island
Clarion Island
Isla Clarión, formerly called Santa Rosa, is the second largest, westernmost and most remote of the Revillagigedo Islands, west of Socorro Island and over from the Mexican mainland and an area ². It has three prominent peaks. The westernmost and tallest peak, Monte Gallegos, is high...
. On July 23, Hernan reached its peak strength of 155 mph (250 km/h) and minimum pressure of 928 mb as the center of circulation was 207 mi (335 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.
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.
Hurricane Iselle
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. 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 20 393 mi (632.5 km) south of Puerto ÁngelPuerto Ángel
Puerto Ángel is a small coastal town in the Mexican state of Oaxaca located in the municipality of San Pedro Pochutla. It, along with San Agustinillo and Playa Zipolite are known as the "Riviera Oaxaqueña. It is located 9 km south of city of Pochutla fifty km west of Huatulco and eighty km...
, Mexico. 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.
The hurricane continued to move west-northwest through its duration, and reached its peak strength of 120 mph (193.1 km/h) on July 25. Iselle crossed Socorro Island, which recorded a 70 mi/h sustained wind and heavy rain on July 25. 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 588 mi (946.3 km) southwest of San Diego.
Tropical Depression Eleven-E
On July 24 a tropical disturbance behind Hurricane Hernan strengthened into a tropical depression. Due to the lose proximity of Hernan 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.Tropical Storm Aka
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 IslandsHawaiian Islands
The Hawaiian Islands are an archipelago of eight major islands, several atolls, numerous smaller islets, and undersea seamounts in the North Pacific Ocean, extending some 1,500 miles from the island of Hawaii in the south to northernmost Kure Atoll...
. On August 10, Tropical Storm Aka peaked with maximum sustained winds of 60 mph (96.6 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. Aka weakened back into a depression and dissipated two days later on August 15.
Tropical Depression Diana
Hurricane Diana struck eastern Mexico and managed to hold together, remaining a tropical depression as it entered the eastern Pacific Ocean late on August 8. Although Tropical Depression Diana entered the eastern Pacific, the National Hurricane Center did not re-classify the system. No re-intensification occurred after the system entered the eastern Pacific, and it had dissipated as a tropical cyclone by the following day. The remnant tropical disturbance recurved through the Gulf of CaliforniaGulf of California
The Gulf of California is a body of water that separates the Baja California Peninsula from the Mexican mainland...
while developing significant convection before it moved into northwest Mexico, which brought rainfall amounts of over 10 in (254 mm) to local areas within the state of Sonora
Sonora
Sonora officially Estado Libre y Soberano de Sonora is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided into 72 municipalities; the capital city is Hermosillo....
. The remnant disturbance moved into the American Southwest on August 11.
Tropical Depression Two-C
Tropical Depression Two-C was the second and last tropical cyclone to develop within the north-central Pacific Ocean in 1990. The depression developed from a tropical disturbance well southeast of HawaiiHawaii
Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...
, 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 mi (965.6 km) south-southeast of Hilo, Hawaii.
Tropical Depression Twelve-E
A persistent area of thunderstorm activity southwest of Puerto VallartaPuerto Vallarta
Puerto Vallarta is a Mexican balneario resort city situated on the Pacific Ocean's Bahía de Banderas.The 2010 census reported Puerto Vallarta's population as 255,725 making it the sixth-largest city in the state of Jalisco...
became better organized and strengthened into Tropical Depression Twelve-E on August 17. Moving northwest, the system developed slowly as it was embedded within the Intertropical Convergence Zone
Intertropical Convergence Zone
The Intertropical Convergence Zone , known by sailors as The Doldrums, is the area encircling the earth near the equator where winds originating in the northern and southern hemispheres come together....
. Easterly shear
Wind shear
Wind shear, sometimes referred to as windshear or wind gradient, is a difference in wind speed and direction over a relatively short distance in the atmosphere...
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.
Hurricane Julio
A tropical wave moved off the western coast of Africa on August 5, moving across the Atlantic Ocean and Caribbean Sea without significant development. 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 404 mi (650.2 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 mph (185.1 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.Hurricane Kenna
A tropical wave moved off the coast of Africa on August 9, and spawned Tropical Storm Fran four days later, before it moved through the southern Windward IslandsWindward Islands
The Windward Islands are the southern islands of the Lesser Antilles, within the West Indies.-Name and geography:The Windward Islands are called such because they were more windward to sailing ships arriving in the New World than the Leeward Islands, given that the prevailing trade winds in the...
on August 14. While Fran dissipated shortly after that, the tropical wave progressed into the northeastern Pacific Ocean. The wave spawned Tropical Depression Fourteen-E 808 mi (1,300.3 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 mph (136.8 km/h) the next day. On August 26, a strong frontal trough
Weather front
A weather front is a boundary separating two masses of air of different densities, and is the principal cause of meteorological phenomena. In surface weather analyses, fronts are depicted using various colored lines and symbols, depending on the type of front...
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.
Hurricane Lowell
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. The cloudiness moved northward toward the Gulf of TehuantepecGulf of Tehuantepec
Gulf of Tehuantepec is a large body of water on the Pacific coast of the Isthmus of Tehuantepec, southeastern Mexico, at . Most of the hurricanes that form in the Eastern Pacific organize in or near this body of water...
on August 22. The thunderstorm activity organized sufficiently for the system to be upgraded to Tropical Depression Fifteen-E on August 23 while 298 mi (479.6 km) southeast of Acapulco, Mexico. The depression moved west-northwestward and strengthened into a tropical storm 217 mi (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 286 mi (460.3 km) southwest of Cabo San Lucas. As the high to the north continued to strengthen, the hurricane turned west-southwest.
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.
Hurricane Marie
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. 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 659 mi (1,060 km) southwest of Clarion Island.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 522 mi (840.1 km) south-southwest of Clarion Island. Marie reached its peak intensity of 140 mph (225.3 km/h) on September 11. The hurricane crossed into the central North Pacific on September 14 as a hurricane with maximum sustained winds of 110 mph (177 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.
Hurricane Norbert
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. Tropical Depression Seventeen-E formed on September 10 while centered 758 mi (1,219.9 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 mph (128.7 km/h) sustained winds that day. Turning north of due west, 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.
Tropical Depression Eighteen-E
On September 12, satellite images indicated that the eighteenth tropical depression of the season formed southwest of Cabo San Lucas. Located in close proximity to Tropical Storm Norbert, the depression would soon enter a region of colder sea surface temperatures, and the National Hurricane Center noted that only very little intensification was possible. As predicted, Norbert hindered further intensification of Tropical Depression Eighteen-E. The National Hurricane Center noted six hours later that the depression would likely be absorbed into Norbert. The National Hurricane Center later believe that Tropical Depression Eighteen-E was "dominating" the interaction between the two systems, and was forecast to absorb Norbert. Unlike the latter prediction, Norbert absorbed Tropical Depression Eighteen-E later that day.Hurricane Odile
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. 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 746 mi (1,200.6 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 mph (233.4 km/h) on September 26.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.
Hurricane Polo
Polo originated from a tropical wave that moved off the African coast on September 2 which spawned Hurricane Isidore in the Atlantic basin1990 Atlantic hurricane season
The 1990 Atlantic hurricane season was the most active Atlantic hurricane season since 1969. It officially began on June 1, 1990, and lasted until November 30, 1990. These dates conventionally delimit the period of each year when most tropical cyclones form 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.
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 mph (120.7 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. There were no casualties or damages caused by Polo.
Tropical Storm Rachel
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 TehuantepecGulf of Tehuantepec
Gulf of Tehuantepec is a large body of water on the Pacific coast of the Isthmus of Tehuantepec, southeastern Mexico, at . Most of the hurricanes that form in the Eastern Pacific organize in or near this body of water...
. On September 27, the organized thunderstorm area was upgraded to Tropical Depression Twenty One-E while 230 mi (370.1 km) south of Acapulco
Acapulco
Acapulco is a city, municipality and major sea port in the state of Guerrero on the Pacific coast of Mexico, southwest from Mexico City. Acapulco is located on a deep, semi-circular bay and has been a port since the early colonial period of Mexico’s history...
. The depression developed slowly, and became a tropical storm on September 30. As Rachel briefly moved northward, before re-curving and accelerating towards the Mexican coast. The storm passed over the southern portion of Baja California Sur
Baja California Sur
Baja California Sur , is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. Before becoming a state on October 8, 1974, the area was known as the South Territory of Baja California. It has an area of , or 3.57% of the land mass of Mexico and comprises...
on October 2. Rachel made its final landfall midway between Los Mochis
Los Mochis
Los Mochis is a coastal city in northern Sinaloa, Mexico. It serves as the municipal seat of the municipality of Ahome. As of the 2010 census, the population was 256,613, which was 61 percent of the municipality's population....
and Culiacán
Culiacán
Culiacán is a city in northwestern Mexico, the largest city in the state of Sinaloa as well as its capital and capital of the municipality of Culiacán. With 675,773 inhabitants in the city , and 858,638 in the municipality, it is the largest city in the state of Sinaloa...
, and became the only system to make landfall from the eastern north Pacific ocean in 1990. Rachel decayed rapidly over land, and the final public advisory on Rachel was issued early on October 3. its remnants continued accelerating over Texas until they lost their identity.
The highest rainfall total from the system in Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
totaled 9.85 in (250.2 mm) at Santa Anita near the tip of Baja California. Across norther, Mexico, thousands were homeless, and 18 people died. In Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
, Rachel's remnants caused heavy rain. Flooding occurred in the Big Bend area.
Tropical Storm Simon
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. The wave moved into the northeastern Pacific waters, off the coast of ColombiaColombia
Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...
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 ITCZ 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 578 mi (930.2 km) south of Cabo San Lucas, Mexico.
The depression continued to develop and was upgraded to Tropical Storm Simon on October 10 while 604 mi (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 mph (112.7 km/h) by late on October 11. 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.
Hurricane Trudy
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.Except for Socorro Island, Trudy had no impact on land. The island reported hurricane force winds for seven hours. Trudy also had an unusually large eye, which was as large as 58 mi (93.3 km) wide. Trudy is the third-strongest Pacific hurricane in October, behind Kenna
Hurricane Kenna
Hurricane Kenna was the second-most intense Pacific hurricane to strike the west coast of Mexico in recorded history. 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...
of the 2002 season and Rick
Hurricane Rick (2009)
Hurricane Rick was the second-most intense Pacific hurricane on record and the strongest ever to form during October. Developing south of Mexico on October 15, 2009, Hurricane Rick traversed an area favoring rapid intensification, allowing it to become a hurricane within 24 hours of being...
of the 2009 season.
Hurricane Vance
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 its duration. Vance weakened to a tropical storm on October 27 and a depression on October 30. The cyclone dissipated late on October 31.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
Accumulated cyclone energy
Accumulated cyclone energy is a measure used by the National Oceanic and Atmospheric Administration to express the activity of individual tropical cyclones and entire tropical cyclone seasons, particularly the North Atlantic hurricane season. It uses an approximation of the energy used by a...
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
140th meridian west
The meridian 140° west of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, North America, the Pacific Ocean, the Southern Ocean, and Antarctica to the South Pole....
; 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
1992 Pacific hurricane season
The 1992 Pacific hurricane season was the most active Pacific hurricane season on record. The most notable storm was Hurricane Iniki, which caused billions of dollars of damage to the Hawaiian Islands. Hurricanes Lester, Virgil, Winifred, and Orlene also made landfall and killed several people, but...
.
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 season1996 Pacific hurricane season
The 1996 Pacific hurricane season was an event in tropical cyclone formation and the third least active Pacific hurricane season in recorded history, behind 1977 and 2010. It officially began May 15, 1996 in the eastern north Pacific and on June 1, 1996 in the central north Pacific. It ended on...
. This is the same list used for the 1984 season
1984 Pacific hurricane season
The 1984 Pacific hurricane season officially started May 15, 1984 in the eastern Pacific, and June 1, 1984 in the central Pacific, and lasted until November 30, 1984. These dates conventionally delimit the period of each year when most tropical cyclones form in the northeastern Pacific...
. Storms were named Trudy and Vance for the first time in 1990. Names that were not assigned are marked in gray.
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One name from the Central Pacific list was used - Aka. It was the first usage for that name.
See also
- List of Pacific hurricanes
- List of Pacific hurricane seasons
- 1990 Atlantic hurricane season1990 Atlantic hurricane seasonThe 1990 Atlantic hurricane season was the most active Atlantic hurricane season since 1969. It officially began on June 1, 1990, and lasted until November 30, 1990. These dates conventionally delimit the period of each year when most tropical cyclones form in the Atlantic basin...
- 1990 Pacific typhoon season1990 Pacific typhoon seasonTropical Storm Lewis was a minimal tropical storm that only held said intensity for 2 days.-Severe Tropical Storm Nathan :A tropical disturbance trekked across the Philippines in mid June, upon entering the South China Sea a depression formed. The depression was upgraded to Tropical Storm Nathan...
- 1990 North Indian Ocean cyclone season1990 North Indian Ocean cyclone seasonOn April 17, an area of convective activity formed to the east of Sri Lanka, and organized itself rapidly before a Tropical Cyclone Formation Alert, was issued later that day. It was designated as Tropical Depression 01B by the JTWC early the next day...
- Southern Hemisphere tropical cyclone seasons: 1989–90, 1990–91
- South Pacific tropical cyclone seasons: 1989–90, 1990-911990–91 South Pacific cyclone seasonThe 1990–91 South Pacific cyclone season was one of the least active cyclone seasons, with only three tropical cyclones occurring within the South Pacific to the east of 160°E. The season officially ran from November 1, 1990, to April 30, 1991 with the first disturbance of the season forming on...