2011 Pacific hurricane season
Encyclopedia
The 2011 Pacific hurricane season is an ongoing, annual cycle of tropical cyclone
formation. The season officially started on May 15, 2011, for the eastern Pacific, and started on June 1, 2011, for the central Pacific, both of which ended on November 30, 2011. These dates conventionally delimit the period of each year when most tropical cyclones form in the Pacific basin. However, the formation of tropical cyclones is possible at any time. The season got off to an active start with first storm, Adrian, becoming one of only a handful of tropical cyclones to attain Category 4 status in June. Four other storms, Dora, Eugene, Hilary, and Kenneth attained Category 4 status. Dora was the strongest storm of the year, peaking at 155 mph, just short of Category 5 status. The month of August was about average in terms of the number of storms, with the strongest of the month being Eugene. However, the first half of September had very little activity, due to the return of a La Niña
event. Tropical Depression Eight-E was the only storm in the first half of September, when it dissipated on September 1. Hilary became the second storm to form in September, becoming the fourth Category 4 hurricane (and the 4th major hurricane of the season), during the afternoon hours of September 22. After Hilary, Jova unexpectedly became the 5th major hurricane of the season during the early morning hours of October 10. Tropical Depression Twelve-E killed 80 people in Central America when it made landfall near El Salvador on October 12. On November 19 Kenneth formed as a tropical depression and quickly strengthened into a hurricane on November 21st. Kenneth became the first major hurricane in November and latest-forming major hurricane in the eastern north Pacific basin in the satellite era; the last to do so was Winnie in 1983, which only peaked at Category 1 status. Hurricane Kenneth, however, intensified to attain Category 4 status on November 22, which broke the record.
On May 19, the Climate Prediction Center
released its pre-season outlook. The scientists stated a 70% chance of a below-normal season, a 25% chance of a near-normal season and a 5% chance of an above-normal season. The climatologists expected 9-15 named storms, with 5-8 becoming hurricanes, and 1-3 becoming major hurricanes. The accumulated cyclone energy
was expected to be 45 to 105% of the median. The below-normal activity forecast was because of increased wind shear and a high expectation of El Niño-Southern Oscillation (ENSO)
-neutral conditions (no El Niño or La Niña
) throughout the peak months of July, August and September, together with lingering La Niña conditions at the beginning of the season. However, as of late November, there have already been eleven named storms, ten hurricanes and six major hurricanes.
moved off the coast of El Salvador
, and into the Pacific Ocean. On June 2, the tropical wave developed a well-defined area of low pressure, which produced disorganized weather, several hundred miles from the Pacific coast of Mexico
. By June 7, the low developed sufficiently organized deep convection
to be classified as a tropical cyclone, and the National Hurricane Center
(NHC) designated it as Tropical Depression One-E at 1500 UTC, about 365 mi (590 km) south of Acapulco
. Upon developing, the depression was located over warm sea surface temperature
s, and upper-level wind shear
in its vicinity was forecast to remain conducive for intensification. Caught in weak steering currents, the system further organized while moving little; it was upgraded to Tropical Storm Adrian later that day, with winds of 60 mph (95 km/h). Briefly caught within light steering winds, Adrian tracked toward the north-northwest. Adrian also began exhibiting an eye-like feature, indicating strengthening is present. By nightfall, the eye-like feature developed into a central dense overcast, a large mass of deep convection, (CDO), and at around 0300 UTC on June 9, the NHC upgraded Adrian to a minimal hurricane as it attained sustained winds of 80 mph (130 km/h). Adrian rapidly deepened
, and over the following 24 hours, it is estimated by satellite observations that winds increased from 80 mph (120 km/h) to 140 mph (240 km/h) and its barometric pressure decreased by 43 mbar
(hPa
; 1.27 inHg), going from a category 1 to a category 4 hurricane on the Saffir–Simpson Hurricane Scale (SSHS). Throughout most of June 9, Adrian began transitioning into a annular hurricane
, displaying a large eye around 25 miles (40.2 km) in diameter, circular in shape, and devoid of any convective banding
. Adrian continued to intensity, reaching its peak intensity at around 0300 UTC on June 10 while located about 320 mi (515 km) south-southwest of Manzanillo, Mexico.
When Adrian peaked, it had maximum sustained winds of 140 mph (220 km/h) and a barometric pressure estimated at 944 mbar
(hPa
; 27.88 inHg). During late that morning, convection associated with the Adrian had lessened and cloud tops warmed. Shortly thereafter, Adrian also began moving into a more stable environment with cooler sea surface temperatures and stronger westerly wind shear. By June 11, Adrian's eye completely disappeared on satellite imagery, and it no longer maintained its symmetrical structure. Steered by a low-to-mid-level ridge over the northeastern Pacific, Adrian recurved to the west, traversing sea surface temperatures cooler than 26.5 °C (79.7 °F). Around 1500 UTC on June 11, Adrian weakened back into a tropical storm. Soon enough, that evening, Adrian degenerated into a tight swirl of low-level clouds. Intermittent bursts of deep convection kept satellite intensity estimates at 45 mph (65 km/h); Adrian still degenerated into a tropical depression six hours later, and subsequently decaying into a remnant low-pressure area without convection, at around 1500 UTC on June 12 while located about 585 mi (940 km) southwest of the southernmost tip of Baja California
, even as the system was accelerating to the north-northwest, while rapidly weakening. But Adrian's remnants still had a slim chance to redevelop, as it began to move southward, while it was located southwest of the Baja California
Peninsula. But as Adrian's remnants remained stationary, it slowly weakened. The possibility of Adrian redeveloping disappeared, as wind shear drastically increased, rapidly destroying the remnants of Adrian. During the late afternoon of June 13, the remnants of Hurricane Adrian dissipated completely, due to the strong wind shear. The outer rainbands of Hurricane Adrian brought widespread rainfall in Mexico
.
over the east Pacific, several hundred miles from the coast of Acapulco, Mexico. A quasi-stationary surface low formed in association with the activity, and over the subsequent days convection consolidated in the vicinity of an anticyclone over the southwestern Caribbean
. Curved rainband
s began developing around the center, and on June 19 the system acquired sufficient organization to be classified as a tropical depression. Turning toward the northwest along a weakness in the subtropical ridge
to its north, the depression further strengthened within a favorable environment and was upgraded to Tropical Storm Beatriz at 1800 UTC that day, with winds of 40 mph (65 km/h).
Late on June 20, Beatriz was upgraded to a hurricane, with winds of 75 mph (121 km/h) and a pressure of 985 mbar (29.1 inHg). Beatriz continued to strengthen and reached winds of 90 mph (140 km/h) and a pressure reading of 977 mbar (28.9 inHg) while it neared the coast of Mexico. After moving along the coast, it weakened to a tropical storm and dissipated the next day. But the NHC noted that Beatriz's remnants still had a near 0% chance of redeveloping, as they remained almost stationary. But on June 23, convection dissipated, and Beatriz's remnants slowly began to accelerate to the west, as the remnant low dissipated rapidly. Late on June 24, the remnants of Hurricane Beatriz dissipated completely, to the southwest of the Baja California
Peninsula.
associated with a broad area of low pressure. The system slowly organized, and the National Hurricane Center designated the system Tropical Depression Three-E on July 7. Around 8 p.m. PDT (0300 UTC July 8) that night, the tropical depression gained enough organization to be named Calvin. Calvin strengthened into a hurricane and attained peak strength late on July 8 before rapidly weakening on July 9. Calvin degenerated into a remnant low early on July 10. During the next 3 days, Calvin's remnants quickly moved to the west, while dissipating rapidly. On July 13, Calvin's remnants dissipated completely, just to the east of the Central Pacific Ocean.
had moved off the Colombia
n coast. The wave gained convection
as it moved into the southwestern Caribbean Sea
, and the National Hurricane Center
(NHC) began to monitor the disturbance, giving it a 10% chance of development into a tropical cyclone. Over the rest of the day, the storm continued to move westward until it moved ashore on the Nicaragua
/Costa Rica
border the next day. On July 16, the National Hurricane Center began monitoring the area of low pressure off the coast of Guatemala. Slowly organizing, the low pressure area had gained enough strength to be declared Tropical Depression Four-E during the morning hours of July 18. Just three hours later, the system was upgraded to Dora, the fourth tropical storm of the 2011 Pacific hurricane season. Continuing to organize, Dora reached hurricane strength late on July 20, before rapidly intensifying into a major hurricane later the next day. Strengthening further, Dora reached a peak of 155 mph (250 km/h) early on July 21, making it a Category 4 hurricane on the Saffir-Simpson hurricane scale
. However, after entering cooler waters, Dora began to weaken the next day. On July 23, Dora was downgraded to a tropical storm, and the next day, Dora was no longer a tropical cyclone. As a remnant low, the circulation began to curve around the high-pressure area that had steered Dora for much of its existence on July 25. Early on July 26, the remnants of Hurricane Dora dissipated completely, over Central Baja California
.
with winds up to 140 mph (220 km/h). Eugene only maintained Category 4 status briefly, and only six hours later, the hurricane weakened to a Category 3 with winds up to 125 mph (200 km/h). Eugene quickly weakened on August 5 because of unfavorable conditions, dropping from Category 2 status to tropical storm status in only 18 hours. On August 6, Eugene became a post-tropical low as the center of the storm was void of strong convection. During the next few days, Eugene's remnants continued to move westward slowly, while weakening gradually. On August 10, the remnants of Hurricane Eugene dissipated roughly 980 mi (1,555 km) east of Hawaii
.
. While shower activity was initially limited, the National Hurricane Center
upgraded it to Tropical Depression Six-E on August 15, and then to Tropical Storm Fernanda on August 16. During the early hours on August 18 Fernanda crossed 140th meridian west
into the Central Pacific Ocean. Fernanda later weakened to a post-tropical cyclone on August 20. During the next 2 days, Fernanda's remnants moved westwards, passing just to the south of Hawaii
. Soon afterwards, the remnants moved to the west of Hawaii. Early on August 23, the remnants of Tropical Storm Fernanda dissipated completely, to the southwest of the Big Island of Hawaii.
, bringing overcast skies, even though the center of circulation itself moved southeastward slowly and was positioned far southwest of Southern California. Greg's remnants continued to drift westwards, as they weakened rapidly. Late on August 24, the remnants of Hurricane Greg dissipated completely, far west of the southern tip, of the Baja California
Peninsula.
(NHC) began to monitor an area of disturbed weather southwest of the Mexican Riviera
. Initially, poorly organized, environmental conditions were conductive for some development. Shortly thereafter, the cloud patterns improved and overall thunderstorm activity increased. Thunderstorm activity become more concentrated two days later while located 60 mi (96.6 km) south of Zinhuatnejo, and the NHC noted that the disturbance could become a tropical depression within hours. This held true, and at 1500 UTC August 31, the low was upgraded into a tropical depression, but no further intensification was anticipated.
Eight-E soon made landfall on Southwestern Mexico
, and moved north-northwestwards, as it rapidly weakened. Eight-E dissipated to a remnant low several hours later, early on September 1. However, the remnants of Tropical Depression Eight-E survived, and they as they began moving westward, the remnants impacted Western Mexico
. During the early afternoon of September 1, the remnants of Eight-E moved off the western coast of Western Mexico. During the next day, the remnants strengthened slightly in intensity, as it moved northwestward, towards the Baja California
Peninsula. But late on September 2, the remnants of Tropical Depression Eight-E dissipated completely, just southeast of Baja California.
began to show signs of organization, while located several hundred miles to the south-southeast of the Gulf of Tehuantepec
. Moving towards the west, and west-northwest, the disturbance gained enough organization early on September 21 to be declared as a tropical depression
, the ninth of the season. Continuing to organize, the depression strengthened into a tropical storm several hours later. On September 22, the meteorologists declared Hilary as a Category 1 hurricane
, becoming the seventh of the season. On September 22, it rapidly strengthened into a small, Category 4 hurricane, featuring a well-defined eye
and very deep convection.
At 00:00 UTC September 23 (8:00 p.m. AST
September 22), Hilary was upgraded into a major hurricane, the fourth of the season. Continuing to rapidly strengthen, Hilary became a Category 4 hurricane just a few hours later after becoming a Category 3, and reached a peak intensity of 145 mph (235 km/h) at 0600 UTC September 23 (11 p.m. AST September 22). However, the storm began to enter an area of higher wind shear and cooler ocean temperatures on September 24, and Hilary began to weaken. The hurricane weakened back down to a Category 3 hurricane early on September 25, but was later upgraded briefly to a Category 4 again the following afternoon. Several hours later, the storm was once again downgraded into a Category 3 hurricane, and during the afternoon hours of September 27, Hilary was further downgraded into a Category 2 hurricane. Early the following morning, Hilary weakened into a Category 1 hurricane, and weakened into a tropical storm on September 28. Losing a lot of its convection on September 30, the National Hurricane Center noted that Hilary had weakened into a tropical depression. Several hours later, after sustaining no deep convection atop its centre, Hilary was declared a remnant low, located several hundred miles away from any landmasses. But over the next few days, Hilary's remnants continued to move northwestward, as a convectionless vortex. By late on October 2, the convectionless swirl had dissipated over Southern California
.
The NHC
noted the possibility of up to 10 in (254 mm) of rain in the high-terrain of Guerrero
and Oaxaca
. Tropical cyclone watches and warnings were also issued for portions of the coast. Large swells were also expected. A red (emergency) alert was issued for parts of the coast. Officials urged residents to be prepared to evacuate. The port of Acapulco
was closed for small craft. A moderate to high alert of rain
and wind
was noted.
The storm's outer bands
produced heavy rain
fall over Chiapas
and Tabasco
, with accumulations in Tabasco reaching 8.58 in (217.9 mm) in 24 hours. Several rivers across the region overflowed their banks and flooded nearby areas. In Villahermosa
, heavy rain collapsed drains and many streets were flooded. In addition, cars were stranded in floodwaters. Across Colima
, waves reached 9 to 15 ft (2.7 to 4.6 m).
associated with a broad low pressure area developed several hundred miles to the south-southwest of Acapulco, Mexico. Moving slowly towards the west, the area of disturbed weather quickly organized. Late on October 5, the National Hurricane Center (NHC) noted that the area had a high chance of developing into a tropical cyclone over the next 48 hours. Just several hours later, the NHC began issuing advisories on Tropical Depression Ten-E, several hundred miles to the south of Manzanillo, Mexico. A more gradual type of development took place after then, and the depression was upgraded into Tropical Storm Jova on the afternoon of October 6. Taking advantage of the favorable environment Jova was embedded within, the storm became a hurricane on October 8, and by October 10, the storm was upgraded to a Category 3 hurricane on the Saffir-Simpson hurricane scale. However, shortly thereafter, the storm began an Eyewall replacement cycle
and weakened to a lower-end Category 2 hurricane. After landfall in Mexico, Jova dissipated.
twice and again re-strengthened back to a tropical storm before finally weakening into a tropical depression on October 15. The depression turned west again and dissipated into a remnant low in the late hours of October 16. But the remnants of Tropical Storm Irwin continued to move westward generally, until it dissipated completely, on October 17.
, became much better organized, and was classified as Tropical Depression Twelve-E. The system, pounded Central America, causing landslides and flooding in Guatemala
, Nicaragua
, El Salvador
and South Western Mexico
. Twelve-E dissipated the next day, but its remnants continued to affect Central America, and at least 80 deaths were confirmed.
. For the next 3 days, the disturbance moved towards the west as it gradually organized, displaying intermittent bursts of intense thunderstorm activity. By November 19, the disturbance had gained enough organization to be declared as a tropical depression, the thirteenth of the season. The following day, the depression continued to intensify, and was upgraded to a tropical storm, receiving the name Kenneth. Rapid strengthening was observed on November 21, and Kenneth was upgraded to a Category 1 hurricane. Later that night, the hurricane became a Category 2 with 105 mph sustained winds. The next morning, Kenneth strengthened to become a strong Category 3 hurricane with sustained winds of 125 mph. Rapid intensification continued and the storm was upgraded to a Category 4 hurricane with sustained winds of 145 mph, just a few hours later, as Kenneth reached its peak intensity. The cause for this rapid intensification just days before the end of the season was unclimatologically low wind shear as well as unusually warm waters directly in Kenneth's path. However, Kenneth's rare and astounding intensification was short-lived; immediately Kenneth moved into an environment of colder waters and stronger wind shear, and Kenneth started to rapidly deteriorate. Just 24 hours after Kenneth reached it's peak strength, it dropped below hurricane strength and lost most of it's central convection. Afterwards Kenneth weakened at a slower rate, but by November 25, Kenneth had weakened to a tropical depression, losing almost all of it's convection. Early on November 25, Kenneth weakened to a remnant low, with it's circulation void of any strong convection. But for the next 2 days, the remnant of Hurricane Kenneth continued moving northwestward rapidly, as a convectionless vortex. Late on November 27, the remnant of Kenneth was absorbed by a large storm to its west, to the southeast of Hawaii
, as Kenneth crashed into the stationary storm. (This occured in the eastern border of the Central Pacific Ocean.)
In the first discussion bulletin, Forecaster Robbie Berg commented that it was the latest-forming tropical cyclone in the North Pacific east of 140°W since Tropical Depression Twenty-Two-E on November 24, 1987, and Kenneth was the latest forming named storm since Winnie in 1983. Kenneth strenghened to a major hurricane on November 22, becoming the latest-forming major hurricane in the eastern north Pacific basin in the satellite
era. Kenneth was upgraded to Category 4 a few hours later, becoming the most powerful late-season storm ever recorded in the eastern north Pacific.
in the spring of 2012. The names not retired from this list will be used again in the 2017 season. This is the same list used in the 2005 season
.
For the central Pacific Ocean, four consecutive lists are used, with the names used sequentially until exhausted, rather than until the end of the year, due to the low number of storms each year. The next four names are shown here:
for each storm in the season. Broadly speaking, the ACE is a measure of the power of a 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 calculated for only full advisories on specifically tropical systems reaching or exceeding wind speeds of 34 knots (39 mph, 63 km/h), or tropical storm strength. Accordingly, tropical depressions are not included here. The ACE also does not include subtropical storms. Later the NHC reexamines the data, and produces a final report on each storm, which can lead to the ACE for a storm being revised either upward or downward. Until the final reports are issued, ACEs are, therefore, provisional.
The figures in parentheses are for storms in the Central Pacific basin west of 140°W
; those not in parentheses are for the Eastern Pacific basin.
Tropical cyclone
A tropical cyclone is a storm system characterized by a large low-pressure center and numerous thunderstorms that produce strong winds and heavy rain. Tropical cyclones strengthen when water evaporated from the ocean is released as the saturated air rises, resulting in condensation of water vapor...
formation. The season officially started on May 15, 2011, for the eastern Pacific, and started on June 1, 2011, for the central Pacific, both of which ended on November 30, 2011. These dates conventionally delimit the period of each year when most tropical cyclones form in the Pacific basin. However, the formation of tropical cyclones is possible at any time. The season got off to an active start with first storm, Adrian, becoming one of only a handful of tropical cyclones to attain Category 4 status in June. Four other storms, Dora, Eugene, Hilary, and Kenneth attained Category 4 status. Dora was the strongest storm of the year, peaking at 155 mph, just short of Category 5 status. The month of August was about average in terms of the number of storms, with the strongest of the month being Eugene. However, the first half of September had very little activity, due to the return of a La Niña
La Niña
La Niña is a coupled ocean-atmosphere phenomenon that is the counterpart of El Niño as part of the broader El Niño-Southern Oscillation climate pattern. During a period of La Niña, the sea surface temperature across the equatorial Eastern Central Pacific Ocean will be lower than normal by 3–5 °C...
event. Tropical Depression Eight-E was the only storm in the first half of September, when it dissipated on September 1. Hilary became the second storm to form in September, becoming the fourth Category 4 hurricane (and the 4th major hurricane of the season), during the afternoon hours of September 22. After Hilary, Jova unexpectedly became the 5th major hurricane of the season during the early morning hours of October 10. Tropical Depression Twelve-E killed 80 people in Central America when it made landfall near El Salvador on October 12. On November 19 Kenneth formed as a tropical depression and quickly strengthened into a hurricane on November 21st. Kenneth became the first major hurricane in November and latest-forming major hurricane in the eastern north Pacific basin in the satellite era; the last to do so was Winnie in 1983, which only peaked at Category 1 status. Hurricane Kenneth, however, intensified to attain Category 4 status on November 22, which broke the record.
Seasonal forecasts
| Source | |Named storms | Hurricanes | Average (1981–2010) | 15.6 | 8.6 | 4.1 | ||
|---|---|---|---|---|---|---|---|---|
| Average (1995–2010) | 14 | 7 | 3 | |||||
| Record high activity | 28 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... |
16 1990 Pacific hurricane season 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... (Tie 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... ) |
10 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... |
|||||
| Record low activity | 8 1977 Pacific hurricane season The 1977 Pacific hurricane season was, at the time, the least active in recorded history. Only eight tropical storms formed, and four hurricanes; they would be tied and surpassed, respectively, by the 2010 Pacific hurricane season. There were no major hurricanes; the next time this happened would... (Tie 2010 Pacific hurricane season The 2010 Pacific hurricane season was the least active Pacific hurricane season, in terms of the number of named storms and hurricanes, on record, due to a moderate La Niña, unlike the 2010 Atlantic hurricane season, which was one of the most active on record... ) |
3 2010 Pacific hurricane season The 2010 Pacific hurricane season was the least active Pacific hurricane season, in terms of the number of named storms and hurricanes, on record, due to a moderate La Niña, unlike the 2010 Atlantic hurricane season, which was one of the most active on record... |
0 1977 Pacific hurricane season The 1977 Pacific hurricane season was, at the time, the least active in recorded history. Only eight tropical storms formed, and four hurricanes; they would be tied and surpassed, respectively, by the 2010 Pacific hurricane season. There were no major hurricanes; the next time this happened would... (Tie 2003 Pacific hurricane season The 2003 Pacific hurricane season produced an unusually large number of tropical cyclones which affected Mexico. The most notable cyclones the year were Hurricanes Ignacio and Marty, which killed 2 and 12 people in Mexico, respectively, and were collectively responsible for about... ) |
|||||
| ––––––––––––––––––––––––––––––––––––––––––––––––––––––– | ||||||||
| NOAA | May 19, 2011 | 9–15 | 5–8 | 1–3 | ||||
| ––––––––––––––––––––––––––––––––––––––––––––––––––––––– | ||||||||
| 11 | 10 | 6 | ||||||
On May 19, the Climate Prediction Center
Climate Prediction Center
The Climate Prediction Center is one of the National Centers for Environmental Prediction, which are a part of NOAA's National Weather Service. It is located in Camp Springs, Maryland.-Products:...
released its pre-season outlook. The scientists stated a 70% chance of a below-normal season, a 25% chance of a near-normal season and a 5% chance of an above-normal season. The climatologists expected 9-15 named storms, with 5-8 becoming hurricanes, and 1-3 becoming major hurricanes. The 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...
was expected to be 45 to 105% of the median. The below-normal activity forecast was because of increased wind shear and a high expectation of El Niño-Southern Oscillation (ENSO)
El Niño-Southern Oscillation
El Niño/La Niña-Southern Oscillation, or ENSO, is a quasiperiodic climate pattern that occurs across the tropical Pacific Ocean roughly every five years...
-neutral conditions (no El Niño or La Niña
La Niña
La Niña is a coupled ocean-atmosphere phenomenon that is the counterpart of El Niño as part of the broader El Niño-Southern Oscillation climate pattern. During a period of La Niña, the sea surface temperature across the equatorial Eastern Central Pacific Ocean will be lower than normal by 3–5 °C...
) throughout the peak months of July, August and September, together with lingering La Niña conditions at the beginning of the season. However, as of late November, there have already been eleven named storms, ten hurricanes and six major hurricanes.
Hurricane Adrian
Late on May 31, a tropical waveTropical 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...
moved off the coast of El Salvador
El Salvador
El Salvador or simply Salvador is the smallest and the most densely populated country in Central America. The country's capital city and largest city is San Salvador; Santa Ana and San Miguel are also important cultural and commercial centers in the country and in all of Central America...
, and into the Pacific Ocean. On June 2, the tropical wave developed a well-defined area of low pressure, which produced disorganized weather, several hundred miles from the Pacific coast of 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...
. By June 7, the low developed sufficiently organized deep convection
Atmospheric convection
Atmospheric convection is the result of a parcel-environment instability, or temperature difference, layer in the atmosphere. Different lapse rates within dry and moist air lead to instability. Mixing of air during the day which expands the height of the planetary boundary layer leads to...
to be classified as a tropical cyclone, and the National Hurricane Center
National Hurricane Center
The National Hurricane Center , located at Florida International University in Miami, Florida, is the division of the National Weather Service responsible for tracking and predicting weather systems within the tropics between the Prime Meridian and the 140th meridian west poleward to the 30th...
(NHC) designated it as Tropical Depression One-E at 1500 UTC, about 365 mi (590 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...
. Upon developing, the depression was located over warm sea surface temperature
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...
s, and upper-level 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...
in its vicinity was forecast to remain conducive for intensification. Caught in weak steering currents, the system further organized while moving little; it was upgraded to Tropical Storm Adrian later that day, with winds of 60 mph (95 km/h). Briefly caught within light steering winds, Adrian tracked toward the north-northwest. Adrian also began exhibiting an eye-like feature, indicating strengthening is present. By nightfall, the eye-like feature developed into a central dense overcast, a large mass of deep convection, (CDO), and at around 0300 UTC on June 9, the NHC upgraded Adrian to a minimal hurricane as it attained sustained winds of 80 mph (130 km/h). Adrian rapidly deepened
Rapid deepening
Rapid deepening, also known as rapid intensification, is a meteorological condition that occurs when the minimum sea-level atmospheric pressure of a tropical cyclone decreases drastically in a short period of time. The National Weather Service describes rapid deepening as a decrease of...
, and over the following 24 hours, it is estimated by satellite observations that winds increased from 80 mph (120 km/h) to 140 mph (240 km/h) and its barometric pressure decreased by 43 mbar
Bar (unit)
The bar is a unit of pressure equal to 100 kilopascals, and roughly equal to the atmospheric pressure on Earth at sea level. Other units derived from the bar are the megabar , kilobar , decibar , centibar , and millibar...
(hPa
Pascal (unit)
The pascal is the SI derived unit of pressure, internal pressure, stress, Young's modulus and tensile strength, named after the French mathematician, physicist, inventor, writer, and philosopher Blaise Pascal. It is a measure of force per unit area, defined as one newton per square metre...
; 1.27 inHg), going from a category 1 to a category 4 hurricane on the Saffir–Simpson Hurricane Scale (SSHS). Throughout most of June 9, Adrian began transitioning into a annular hurricane
Annular hurricane
An annular hurricane, also known as a truck tire or doughnut hurricane, is a tropical cyclone in the Atlantic or Eastern Pacific Oceans that features a large, symmetric eye surrounded by a thick ring of intense convection. This type of storm is not prone to the fluctuations in intensity associated...
, displaying a large eye around 25 miles (40.2 km) in diameter, circular in shape, and devoid of any convective banding
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...
. Adrian continued to intensity, reaching its peak intensity at around 0300 UTC on June 10 while located about 320 mi (515 km) south-southwest of Manzanillo, Mexico.
When Adrian peaked, it had maximum sustained winds of 140 mph (220 km/h) and a barometric pressure estimated at 944 mbar
Bar (unit)
The bar is a unit of pressure equal to 100 kilopascals, and roughly equal to the atmospheric pressure on Earth at sea level. Other units derived from the bar are the megabar , kilobar , decibar , centibar , and millibar...
(hPa
Pascal (unit)
The pascal is the SI derived unit of pressure, internal pressure, stress, Young's modulus and tensile strength, named after the French mathematician, physicist, inventor, writer, and philosopher Blaise Pascal. It is a measure of force per unit area, defined as one newton per square metre...
; 27.88 inHg). During late that morning, convection associated with the Adrian had lessened and cloud tops warmed. Shortly thereafter, Adrian also began moving into a more stable environment with cooler sea surface temperatures and stronger westerly wind shear. By June 11, Adrian's eye completely disappeared on satellite imagery, and it no longer maintained its symmetrical structure. Steered by a low-to-mid-level ridge over the northeastern Pacific, Adrian recurved to the west, traversing sea surface temperatures cooler than 26.5 °C (79.7 °F). Around 1500 UTC on June 11, Adrian weakened back into a tropical storm. Soon enough, that evening, Adrian degenerated into a tight swirl of low-level clouds. Intermittent bursts of deep convection kept satellite intensity estimates at 45 mph (65 km/h); Adrian still degenerated into a tropical depression six hours later, and subsequently decaying into a remnant low-pressure area without convection, at around 1500 UTC on June 12 while located about 585 mi (940 km) southwest of the southernmost tip of Baja California
Baja California Peninsula
The Baja California peninsula , is a peninsula in northwestern Mexico. Its land mass separates the Pacific Ocean from the Gulf of California. The Peninsula extends from Mexicali, Baja California in the north to Cabo San Lucas, Baja California Sur in the south.The total area of the Baja California...
, even as the system was accelerating to the north-northwest, while rapidly weakening. But Adrian's remnants still had a slim chance to redevelop, as it began to move southward, while it was located southwest of the 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...
Peninsula. But as Adrian's remnants remained stationary, it slowly weakened. The possibility of Adrian redeveloping disappeared, as wind shear drastically increased, rapidly destroying the remnants of Adrian. During the late afternoon of June 13, the remnants of Hurricane Adrian dissipated completely, due to the strong wind shear. The outer rainbands of Hurricane Adrian brought widespread rainfall 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...
.
Hurricane Beatriz
On June 14, the NHC noted a large area of scattered showers and thunderstorms associated with a monsoon troughMonsoon trough
The monsoon trough is that portion of the Intertropical Convergence Zone which extends into or through a monsoon circulation, as depicted by a line on a weather map showing the locations of minimum sea level pressure, and as such, is a convergence zone between the wind patterns of the southern and...
over the east Pacific, several hundred miles from the coast of Acapulco, Mexico. A quasi-stationary surface low formed in association with the activity, and over the subsequent days convection consolidated in the vicinity of an anticyclone over the southwestern Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
. Curved 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 began developing around the center, and on June 19 the system acquired sufficient organization to be classified as a tropical depression. Turning toward the northwest along a weakness in the 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...
to its north, the depression further strengthened within a favorable environment and was upgraded to Tropical Storm Beatriz at 1800 UTC that day, with winds of 40 mph (65 km/h).
Late on June 20, Beatriz was upgraded to a hurricane, with winds of 75 mph (121 km/h) and a pressure of 985 mbar (29.1 inHg). Beatriz continued to strengthen and reached winds of 90 mph (140 km/h) and a pressure reading of 977 mbar (28.9 inHg) while it neared the coast of Mexico. After moving along the coast, it weakened to a tropical storm and dissipated the next day. But the NHC noted that Beatriz's remnants still had a near 0% chance of redeveloping, as they remained almost stationary. But on June 23, convection dissipated, and Beatriz's remnants slowly began to accelerate to the west, as the remnant low dissipated rapidly. Late on June 24, the remnants of Hurricane Beatriz dissipated completely, to the southwest of the 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...
Peninsula.
Hurricane Calvin
On July 5, an area of showers and thunderstorms formed 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...
associated with a broad area of low pressure. The system slowly organized, and the National Hurricane Center designated the system Tropical Depression Three-E on July 7. Around 8 p.m. PDT (0300 UTC July 8) that night, the tropical depression gained enough organization to be named Calvin. Calvin strengthened into a hurricane and attained peak strength late on July 8 before rapidly weakening on July 9. Calvin degenerated into a remnant low early on July 10. During the next 3 days, Calvin's remnants quickly moved to the west, while dissipating rapidly. On July 13, Calvin's remnants dissipated completely, just to the east of the Central Pacific Ocean.
Hurricane Dora
In the early morning hours of July 14, a tropical waveTropical 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...
had moved off the Colombia
Colombia
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...
n coast. The wave gained 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....
as it moved into the southwestern Caribbean Sea
Caribbean Sea
The Caribbean Sea is a sea of the Atlantic Ocean located in the tropics of the Western hemisphere. It is bounded by Mexico and Central America to the west and southwest, to the north by the Greater Antilles, and to the east by the Lesser Antilles....
, and the National Hurricane Center
National Hurricane Center
The National Hurricane Center , located at Florida International University in Miami, Florida, is the division of the National Weather Service responsible for tracking and predicting weather systems within the tropics between the Prime Meridian and the 140th meridian west poleward to the 30th...
(NHC) began to monitor the disturbance, giving it a 10% chance of development into a tropical cyclone. Over the rest of the day, the storm continued to move westward until it moved ashore on the Nicaragua
Nicaragua
Nicaragua is the largest country in the Central American American isthmus, bordered by Honduras to the north and Costa Rica to the south. The country is situated between 11 and 14 degrees north of the Equator in the Northern Hemisphere, which places it entirely within the tropics. The Pacific Ocean...
/Costa Rica
Costa Rica
Costa Rica , officially the Republic of Costa Rica is a multilingual, multiethnic and multicultural country in Central America, bordered by Nicaragua to the north, Panama to the southeast, the Pacific Ocean to the west and the Caribbean Sea to the east....
border the next day. On July 16, the National Hurricane Center began monitoring the area of low pressure off the coast of Guatemala. Slowly organizing, the low pressure area had gained enough strength to be declared Tropical Depression Four-E during the morning hours of July 18. Just three hours later, the system was upgraded to Dora, the fourth tropical storm of the 2011 Pacific hurricane season. Continuing to organize, Dora reached hurricane strength late on July 20, before rapidly intensifying into a major hurricane later the next day. Strengthening further, Dora reached a peak of 155 mph (250 km/h) early on July 21, making it a Category 4 hurricane 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...
. However, after entering cooler waters, Dora began to weaken the next day. On July 23, Dora was downgraded to a tropical storm, and the next day, Dora was no longer a tropical cyclone. As a remnant low, the circulation began to curve around the high-pressure area that had steered Dora for much of its existence on July 25. Early on July 26, the remnants of Hurricane Dora dissipated completely, over Central 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...
.
Hurricane Eugene
On early July 31, a tropical wave developed into a tropical depression in the eastern Pacific a few hundred miles south of Mexico. Meteorologists numbered it "Five-E". It was upgraded to Tropical Storm Eugene only 6 hours after becoming a tropical depression. On the afternoon of August 1, Eugene strengthened into a Category 1 hurricane on the Saffir-Simpson Hurricane Scale. The next day Eugene further strengthened into a Category 2 hurricane. Early on August 3 Eugene further strengthened into a Category 3 hurricane, making it the third major hurricane of the season. Eugene was expected to weaken after becoming a Category 3. However, on the afternoon of August 3, Eugene strengthened into a Category 4 hurricane on the Saffir-Simpson Hurricane ScaleSaffir-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...
with winds up to 140 mph (220 km/h). Eugene only maintained Category 4 status briefly, and only six hours later, the hurricane weakened to a Category 3 with winds up to 125 mph (200 km/h). Eugene quickly weakened on August 5 because of unfavorable conditions, dropping from Category 2 status to tropical storm status in only 18 hours. On August 6, Eugene became a post-tropical low as the center of the storm was void of strong convection. During the next few days, Eugene's remnants continued to move westward slowly, while weakening gradually. On August 10, the remnants of Hurricane Eugene dissipated roughly 980 mi (1,555 km) east of Hawaii
Hawaii
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...
.
Tropical Storm Fernanda
During the afternoon hours on August 13 an area with a group of thunderstorms associated with an area of low pressure formed over the open PacificPacific 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...
. While shower activity was initially limited, the National Hurricane Center
National Hurricane Center
The National Hurricane Center , located at Florida International University in Miami, Florida, is the division of the National Weather Service responsible for tracking and predicting weather systems within the tropics between the Prime Meridian and the 140th meridian west poleward to the 30th...
upgraded it to Tropical Depression Six-E on August 15, and then to Tropical Storm Fernanda on August 16. During the early hours on August 18 Fernanda crossed 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....
into the Central Pacific Ocean. Fernanda later weakened to a post-tropical cyclone on August 20. During the next 2 days, Fernanda's remnants moved westwards, passing just to the south of Hawaii
Hawaii
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...
. Soon afterwards, the remnants moved to the west of Hawaii. Early on August 23, the remnants of Tropical Storm Fernanda dissipated completely, to the southwest of the Big Island of Hawaii.
Hurricane Greg
On the afternoon of August 16, a vigorous area of low pressure developed into Tropical Depression Seven-E. It was upgraded to Tropical Storm Greg 12 hours after formation. The storm steadily intensified over 85 °F (29.4 °C) sea surface temperatures and it reached hurricane status late on August 17 with maximum sustained winds of 75 mph. Greg continued strengthening to attain peak winds of 85 mph and a pressure of 980 mbar. Soon afterward, the storm began to gradually weaken due to cooler waters and higher wind shear and on August 19, Greg weakened to tropical storm strength, with maximum sustained winds of 65 mph. The storm continued to weaken as it encountered unfavorable wind shear and as it began to traverse cooler waters, and on August 20 Greg had weakened to a tropical depression. Greg maintained tropical depression status until August 21, when it degenerated into a remnant low. During that day, Greg's remnants moved northeastward due to a High Pressure System. From late on August 22, until the early afternoon of August 23, Greg's remnants impacted southern CaliforniaSouthern California
Southern California is a megaregion, or megapolitan area, in the southern area of the U.S. state of California. Large urban areas include Greater Los Angeles and Greater San Diego. The urban area stretches along the coast from Ventura through the Southland and Inland Empire to San Diego...
, bringing overcast skies, even though the center of circulation itself moved southeastward slowly and was positioned far southwest of Southern California. Greg's remnants continued to drift westwards, as they weakened rapidly. Late on August 24, the remnants of Hurricane Greg dissipated completely, far west of the southern tip, of the 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...
Peninsula.
Tropical Depression Eight-E
The National Hurricane CenterNational Hurricane Center
The National Hurricane Center , located at Florida International University in Miami, Florida, is the division of the National Weather Service responsible for tracking and predicting weather systems within the tropics between the Prime Meridian and the 140th meridian west poleward to the 30th...
(NHC) began to monitor an area of disturbed weather southwest of the Mexican Riviera
Mexican Riviera
The Mexican Riviera refers collectively to twenty cities and lagoons lying on the western coast of Mexico. Although there are long distances between these cities, they are often referred to as the Mexican Riviera because of their popularity among tourists. Cruise ships often visit three or four of...
. Initially, poorly organized, environmental conditions were conductive for some development. Shortly thereafter, the cloud patterns improved and overall thunderstorm activity increased. Thunderstorm activity become more concentrated two days later while located 60 mi (96.6 km) south of Zinhuatnejo, and the NHC noted that the disturbance could become a tropical depression within hours. This held true, and at 1500 UTC August 31, the low was upgraded into a tropical depression, but no further intensification was anticipated.
Eight-E soon made landfall on Southwestern Mexico
Southwestern Mexico
Southwestern Mexico is a region of Mexico, formed by the states of Chiapas, Guerrero and Oaxaca.Because of its population is mostly indigenous people, these states are famous for the deep roots of their traditions, holidays, crafts and great food...
, and moved north-northwestwards, as it rapidly weakened. Eight-E dissipated to a remnant low several hours later, early on September 1. However, the remnants of Tropical Depression Eight-E survived, and they as they began moving westward, the remnants impacted Western Mexico
Western Mexico
The Western Mexico is a region of United Mexican States, formed by the states of Jalisco, Nayarit, Colima and Michoacan, also includes the Revillagigedo Islands, Marías Islands and several smaller islands...
. During the early afternoon of September 1, the remnants of Eight-E moved off the western coast of Western Mexico. During the next day, the remnants strengthened slightly in intensity, as it moved northwestward, towards the 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...
Peninsula. But late on September 2, the remnants of Tropical Depression Eight-E dissipated completely, just southeast of Baja California.
Hurricane Hilary
On September 18, a broad area of low pressure associated with minimal shower and thunderstorm activityAtmospheric convection
Atmospheric convection is the result of a parcel-environment instability, or temperature difference, layer in the atmosphere. Different lapse rates within dry and moist air lead to instability. Mixing of air during the day which expands the height of the planetary boundary layer leads to...
began to show signs of organization, while located several hundred miles to the south-southeast of the Gulf of Tehuantepec
Gulf 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...
. Moving towards the west, and west-northwest, the disturbance gained enough organization early on September 21 to be declared as a tropical depression
Tropical cyclone
A tropical cyclone is a storm system characterized by a large low-pressure center and numerous thunderstorms that produce strong winds and heavy rain. Tropical cyclones strengthen when water evaporated from the ocean is released as the saturated air rises, resulting in condensation of water vapor...
, the ninth of the season. Continuing to organize, the depression strengthened into a tropical storm several hours later. On September 22, the meteorologists declared Hilary as a Category 1 hurricane
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...
, becoming the seventh of the season. On September 22, it rapidly strengthened into a small, Category 4 hurricane, featuring a well-defined eye
Eye (cyclone)
The eye is a region of mostly calm weather found at the center of strong tropical cyclones. The eye of a storm is a roughly circular area and typically 30–65 km in diameter. It is surrounded by the eyewall, a ring of towering thunderstorms where the second most severe weather of a cyclone...
and very deep convection.
At 00:00 UTC September 23 (8:00 p.m. AST
Atlantic Standard Time Zone
The Atlantic Standard Time Zone is a geographical region that keeps time by subtracting four hours from either Coordinated Universal Time or Greenwich Mean Time , resulting in UTC-4 or GMT-4...
September 22), Hilary was upgraded into a major hurricane, the fourth of the season. Continuing to rapidly strengthen, Hilary became a Category 4 hurricane just a few hours later after becoming a Category 3, and reached a peak intensity of 145 mph (235 km/h) at 0600 UTC September 23 (11 p.m. AST September 22). However, the storm began to enter an area of higher wind shear and cooler ocean temperatures on September 24, and Hilary began to weaken. The hurricane weakened back down to a Category 3 hurricane early on September 25, but was later upgraded briefly to a Category 4 again the following afternoon. Several hours later, the storm was once again downgraded into a Category 3 hurricane, and during the afternoon hours of September 27, Hilary was further downgraded into a Category 2 hurricane. Early the following morning, Hilary weakened into a Category 1 hurricane, and weakened into a tropical storm on September 28. Losing a lot of its convection on September 30, the National Hurricane Center noted that Hilary had weakened into a tropical depression. Several hours later, after sustaining no deep convection atop its centre, Hilary was declared a remnant low, located several hundred miles away from any landmasses. But over the next few days, Hilary's remnants continued to move northwestward, as a convectionless vortex. By late on October 2, the convectionless swirl had dissipated over Southern California
Southern California
Southern California is a megaregion, or megapolitan area, in the southern area of the U.S. state of California. Large urban areas include Greater Los Angeles and Greater San Diego. The urban area stretches along the coast from Ventura through the Southland and Inland Empire to San Diego...
.
The NHC
National Hurricane Center
The National Hurricane Center , located at Florida International University in Miami, Florida, is the division of the National Weather Service responsible for tracking and predicting weather systems within the tropics between the Prime Meridian and the 140th meridian west poleward to the 30th...
noted the possibility of up to 10 in (254 mm) of rain in the high-terrain of Guerrero
Guerrero
Guerrero officially Estado Libre y Soberano de Guerrero is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 81 municipalities and its capital city is Chilpancingo....
and Oaxaca
Oaxaca
Oaxaca , , officially Estado Libre y Soberano de Oaxaca is one of the 31 states which, along with the Federal District, comprise the 32 federative entities of Mexico. It is divided into 571 municipalities; of which 418 are governed by the system of customs and traditions...
. Tropical cyclone watches and warnings were also issued for portions of the coast. Large swells were also expected. A red (emergency) alert was issued for parts of the coast. Officials urged residents to be prepared to evacuate. The port 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...
was closed for small craft. A moderate to high alert of rain
Rain
Rain is liquid precipitation, as opposed to non-liquid kinds of precipitation such as snow, hail and sleet. Rain requires the presence of a thick layer of the atmosphere to have temperatures above the melting point of water near and above the Earth's surface...
and wind
Wind
Wind is the flow of gases on a large scale. On Earth, wind consists of the bulk movement of air. In outer space, solar wind is the movement of gases or charged particles from the sun through space, while planetary wind is the outgassing of light chemical elements from a planet's atmosphere into space...
was noted.
The storm's outer bands
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...
produced heavy rain
Heavy Rain
Heavy Rain is an interactive drama psychological thriller video game created by Quantic Dream exclusively for the PlayStation 3. The game is written and directed by Quantic Dream's founder and CEO David Cage....
fall over Chiapas
Chiapas
Chiapas officially Estado Libre y Soberano de Chiapas is one of the 31 states that, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 118 municipalities and its capital city is Tuxtla Gutierrez. Other important cites in Chiapas include San Cristóbal de las...
and Tabasco
Tabasco
Tabasco officially Estado Libre y Soberano de Tabasco is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 17 municipalities and its capital city is Villahermosa....
, with accumulations in Tabasco reaching 8.58 in (217.9 mm) in 24 hours. Several rivers across the region overflowed their banks and flooded nearby areas. In Villahermosa
Villahermosa
Like most of the Tabasco, Villahermosa has a tropical climate. The city specifically features a tropical monsoon climate. Temperatures during spring and summer seasons reach upwards of 40°C , with humidity levels hovering around 30% during the same period...
, heavy rain collapsed drains and many streets were flooded. In addition, cars were stranded in floodwaters. Across Colima
Colima
Colima is one of the 31 states which, with the Federal District, make up the 32 Federal Entities of Mexico. It shares its name with its capital and main city, Colima....
, waves reached 9 to 15 ft (2.7 to 4.6 m).
Hurricane Jova
During the late hours of October 4, an area of showers and thunderstormsAtmospheric convection
Atmospheric convection is the result of a parcel-environment instability, or temperature difference, layer in the atmosphere. Different lapse rates within dry and moist air lead to instability. Mixing of air during the day which expands the height of the planetary boundary layer leads to...
associated with a broad low pressure area developed several hundred miles to the south-southwest of Acapulco, Mexico. Moving slowly towards the west, the area of disturbed weather quickly organized. Late on October 5, the National Hurricane Center (NHC) noted that the area had a high chance of developing into a tropical cyclone over the next 48 hours. Just several hours later, the NHC began issuing advisories on Tropical Depression Ten-E, several hundred miles to the south of Manzanillo, Mexico. A more gradual type of development took place after then, and the depression was upgraded into Tropical Storm Jova on the afternoon of October 6. Taking advantage of the favorable environment Jova was embedded within, the storm became a hurricane on October 8, and by October 10, the storm was upgraded to a Category 3 hurricane on the Saffir-Simpson hurricane scale. However, shortly thereafter, the storm began an Eyewall replacement cycle
Eyewall replacement cycle
Eyewall replacement cycles, also called concentric eyewall cycles, naturally occur in intense tropical cyclones, generally with winds greater than 185 km/h , or major hurricanes...
and weakened to a lower-end Category 2 hurricane. After landfall in Mexico, Jova dissipated.
Hurricane Irwin
The origins of Hurricane Irwin can be tracked back to an area of showers and thunderstorms associated with a low pressure area that developed several hundred miles to the south of Mexico. Moving towards the west and west-northwest, the low pressure quickly gained organization, and during the pre-dawn hours of October 6, the National Hurricane Center began issuing advisories on newly formed Tropical Depression Eleven-E. Later on October 6, Tropical Depression Eleven-E strengthened to Tropical Storm Irwin, and it became a hurricane the next day. The next day it weakened to a tropical storm. Unlike most tropical cyclones that form in the eastern Pacific ocean, Irwin's track was very unusual. The system which originally started moving westward, turned north, then east and again back south, and east until dissipation, on October 17, as a remnant low. Also, between October 11 and 14, Irwin weakened into a tropical depressionSaffir-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...
twice and again re-strengthened back to a tropical storm before finally weakening into a tropical depression on October 15. The depression turned west again and dissipated into a remnant low in the late hours of October 16. But the remnants of Tropical Storm Irwin continued to move westward generally, until it dissipated completely, on October 17.
Tropical Depression Twelve-E
On October 12, an area of low pressure just 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...
, became much better organized, and was classified as Tropical Depression Twelve-E. The system, pounded Central America, causing landslides and flooding in Guatemala
Guatemala
Guatemala is a country in Central America bordered by Mexico to the north and west, the Pacific Ocean to the southwest, Belize to the northeast, the Caribbean to the east, and Honduras and El Salvador to the southeast...
, Nicaragua
Nicaragua
Nicaragua is the largest country in the Central American American isthmus, bordered by Honduras to the north and Costa Rica to the south. The country is situated between 11 and 14 degrees north of the Equator in the Northern Hemisphere, which places it entirely within the tropics. The Pacific Ocean...
, El Salvador
El Salvador
El Salvador or simply Salvador is the smallest and the most densely populated country in Central America. The country's capital city and largest city is San Salvador; Santa Ana and San Miguel are also important cultural and commercial centers in the country and in all of Central America...
and South Western 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...
. Twelve-E dissipated the next day, but its remnants continued to affect Central America, and at least 80 deaths were confirmed.
Hurricane Kenneth
Early on November 16, an area of disturbed weather formed several hundred miles to the south of the southern coast of GuatemalaGuatemala
Guatemala is a country in Central America bordered by Mexico to the north and west, the Pacific Ocean to the southwest, Belize to the northeast, the Caribbean to the east, and Honduras and El Salvador to the southeast...
. For the next 3 days, the disturbance moved towards the west as it gradually organized, displaying intermittent bursts of intense thunderstorm activity. By November 19, the disturbance had gained enough organization to be declared as a tropical depression, the thirteenth of the season. The following day, the depression continued to intensify, and was upgraded to a tropical storm, receiving the name Kenneth. Rapid strengthening was observed on November 21, and Kenneth was upgraded to a Category 1 hurricane. Later that night, the hurricane became a Category 2 with 105 mph sustained winds. The next morning, Kenneth strengthened to become a strong Category 3 hurricane with sustained winds of 125 mph. Rapid intensification continued and the storm was upgraded to a Category 4 hurricane with sustained winds of 145 mph, just a few hours later, as Kenneth reached its peak intensity. The cause for this rapid intensification just days before the end of the season was unclimatologically low wind shear as well as unusually warm waters directly in Kenneth's path. However, Kenneth's rare and astounding intensification was short-lived; immediately Kenneth moved into an environment of colder waters and stronger wind shear, and Kenneth started to rapidly deteriorate. Just 24 hours after Kenneth reached it's peak strength, it dropped below hurricane strength and lost most of it's central convection. Afterwards Kenneth weakened at a slower rate, but by November 25, Kenneth had weakened to a tropical depression, losing almost all of it's convection. Early on November 25, Kenneth weakened to a remnant low, with it's circulation void of any strong convection. But for the next 2 days, the remnant of Hurricane Kenneth continued moving northwestward rapidly, as a convectionless vortex. Late on November 27, the remnant of Kenneth was absorbed by a large storm to its west, to the southeast of Hawaii
Hawaii
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...
, as Kenneth crashed into the stationary storm. (This occured in the eastern border of the Central Pacific Ocean.)
In the first discussion bulletin, Forecaster Robbie Berg commented that it was the latest-forming tropical cyclone in the North Pacific east of 140°W since Tropical Depression Twenty-Two-E on November 24, 1987, and Kenneth was the latest forming named storm since Winnie in 1983. Kenneth strenghened to a major hurricane on November 22, becoming the latest-forming major hurricane in the eastern north Pacific basin in the satellite
Satellite
In the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....
era. Kenneth was upgraded to Category 4 a few hours later, becoming the most powerful late-season storm ever recorded in the eastern north Pacific.
Storm names
The following names will be used for named storms that form in the North East Pacific in 2011. Retired names, if any, will be announced by the World Meteorological OrganizationWorld Meteorological Organization
The World Meteorological Organization is an intergovernmental organization with a membership of 189 Member States and Territories. It originated from the International Meteorological Organization , which was founded in 1873...
in the spring of 2012. The names not retired from this list will be used again in the 2017 season. This is the same list used in the 2005 season
2005 Pacific hurricane season
The 2005 Pacific hurricane season officially began on May 15, 2005 in the eastern Pacific and on June 1, 2005 in the central Pacific, and lasted until November 30, 2005. These dates conventionally delimit the period of each year when most tropical cyclones form in the northeastern Pacific Ocean...
.
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Hurricane Jova (2011) Hurricane Jova was a powerful Pacific hurricane that made landfall over Jalisco, Mexico. The tenth tropical depression and storm, as well as the ninth hurricane of the 2011 Pacific hurricane season, Jova developed from an area of showers and thunderstorms that became better organized in early October... |
For the central Pacific Ocean, four consecutive lists are used, with the names used sequentially until exhausted, rather than until the end of the year, due to the low number of storms each year. The next four names are shown here:
Season effects
This is a table of all of the storms in the 2011 Pacific hurricane season. It includes their durations, peak intensities, names, landfall(s), damages, and death totals. Deaths in parentheses are additional and indirect (an example of an indirect death would be a traffic accident), but are still storm-related. Damage and deaths include totals while the storm was extratropical or a wave or a low. All of the damage figures are in 2011 USD.Accumulated Cyclone Energy (ACE)
The table on the right shows the ACEAccumulated 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. Broadly speaking, the ACE is a measure of the power of a 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 calculated for only full advisories on specifically tropical systems reaching or exceeding wind speeds of 34 knots (39 mph, 63 km/h), or tropical storm strength. Accordingly, tropical depressions are not included here. The ACE also does not include subtropical storms. Later the NHC reexamines the data, and produces a final report on each storm, which can lead to the ACE for a storm being revised either upward or downward. Until the final reports are issued, ACEs are, therefore, provisional.
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 parentheses are for the Eastern Pacific basin.
See also
- List of Pacific hurricanes
- List of Pacific hurricane seasons
- 2011 Atlantic hurricane season2011 Atlantic hurricane seasonThe 2011 Atlantic hurricane season is tied for the third most active season on record with 1887, 1995 and 2010. It began on June 1, 2011, and ended on November 30, 2011, however these dates conventionally delimit the period of each year when most tropical cyclones develop in the Atlantic basin...
- 2011 Pacific typhoon season2011 Pacific typhoon seasonThe 2011 Pacific typhoon season was the time of the year in which tropical cyclones form in the Western Pacific Ocean. The season ran throughout 2011 with most tropical cyclones forming between May and November. The scope of this article is limited to the Pacific Ocean to the north of the equator...
- 2011 North Indian Ocean cyclone season2011 North Indian Ocean cyclone seasonThe 2011 North Indian Ocean cyclone season is an event in the annual cycle of tropical cyclone formation. The North Indian Ocean cyclone season has no official bounds, but cyclones tend to form between April and December, with peaks in May and November...
- South-West Indian Ocean cyclone seasons: 2010–112010–11 South-West Indian Ocean cyclone seasonThe 2010–11 South-West Indian Ocean cyclone season was the least active tropical cyclone season in the South-West Indian Ocean on record. It began on November 1, 2010 and ended on April 30, 2011, dates which conventionally delimit the year in which most tropical cyclones form in the basin...
, 2011–122011–12 South-West Indian Ocean cyclone seasonThe 2011–12 South-West Indian Ocean cyclone season is an event in the annual cycle of tropical cyclone formation. It began on November 15, 2011, and will end on April 30, 2012, with the exception for Mauritius and the Seychelles, for which it will end on May 15, 2012... - Australian region cyclone seasons: 2010–112010–11 Australian region cyclone seasonThe 2010–11 Australian region cyclone season was a near average tropical cyclone season, with eleven tropical cyclones forming compared to an average of 12. The season began on 1 November 2010 and ended on 30 April 2011. The Australian region is defined as being to south of the equator, between the...
, 2011–122011–12 Australian region cyclone seasonThe 2011–12 Australian region cyclone season is an event in the ongoing cycle of tropical cyclone formation. It began on 1 November 2011, and it will end on 30 April 2012... - South Pacific cyclone seasons: 2010–112010–11 South Pacific cyclone seasonThe 2010–11 South Pacific cyclone season is a period of the year when tropical cyclones formed within the South Pacific Ocean to the east of 160°E...
, 2011–122011–12 South Pacific cyclone seasonThe 2011–12 South Pacific cyclone season will be the period of the year when most tropical cyclones form within the South Pacific Ocean to the east of 160°E. The season officially runs from November 1, 2011 to April 30, 2012...