Hurricane Dora (2011)
Encyclopedia
Hurricane Dora was a very powerful and intense hurricane and the second of four Category 4 hurricanes
during the 2011 Pacific hurricane season
. The fourth tropical depression, named storm, hurricane, and second major hurricane of the season, Dora developed a from a tropical wave
on July 18. Quickly intensifying, the new tropical depression became a tropical storm just three hours after formation. The storm began to explosively intensify
on July 20, strengthening from a minimal hurricane to a category 4 in only 17 hours. Dora reached its peak strength during the early morning hours of July 21 with maximum sustained winds of 155 mph (250 km/h) and a minimum central pressure of 929 mbar, just 1 mile per hour short of Category 5 status. However, as quickly as Dora strengthened, it weakened. Cooler waters and wind shear
began to weaken the hurricane, and by the end of July 22, Dora had already weakened to a tropical storm and soon dissipated on July 24, just west of the Baja California Peninsula.
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. The tropical wave emerged into the Pacific Ocean
on July 16 under favorable conditions for development. The system strengthened and became better organized the next few days as the once disorganized system of thunderstorms began to collect towards the center.
At 1500 UTC July 18, the disturbance was designated as Tropical Depression Four-E. By the time Four-E was designated, well-defined bands
of convection and a tight inner wind field were observed. Despite modest northerly upper-level winds, the depression strengthened into a tropical storm, receiving the name Dora. Dora began to move west-northwestwards under the influence of a strong high pressure system
. Gradual intensification ensued, and an eye began to form in Dora the next day. Late on July 19, Dora attained hurricane status with hurricane-force winds extending up to 35 miles (55 km) from the center as the eyewall contracted. Dora continued to gradually strengthen early on July 20. However, in the afternoon, Hurricane Dora rapidly intensified
to a major hurricane, the second of the season with winds of 115 miles per hour (185.1 km/h) and higher gusts. The inner core solidified and eyewall mesovortices were hinted. Dora continued to quickly intensify, becoming a category 4 hurricane just hours later with maximum wind speeds of 135 miles per hour (217.3 km/h) and a hurricane-force wind field extending to a 40 miles (64.4 km) radius. The next day, Dora began to take on the appearance of an annular hurricane
, with an eye similar to those seen in Hurricane Isabel. Continuing to rapidly intensify, Hurricane Dora attained peak intensity later on July 21 with winds of 155 miles per hour (249.4 km/h) and a central minimum pressure of 929 mbar (hPa; 27.43 inHg) while 445 miles (715 km) south-southeast of Cabo San Lucas, Mexico.
However, Dora began to traverse colder waters and encountered unfavorable wind shear. The eye abruptly dissipated and convection became much less organized. Within 12 hours, Dora already weakened into a category 3 hurricane. On July 22, the low-level circulation center became exposed as convection shifted to the southern semicircle
. Dora continued to be sheared by strong northwesterly wind shear as it quickly weakened. Dora's satellite signature deteriorated along with much of its convection. The hurricane was downgraded to a tropical storm late on July 22 as it moved into hostile atmospheric conditions and cooler water. Based on data from Hurricane Hunters
, the NHC issued its last advisory for Dora on the evening of July 24. 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
.
. Another watch was soon posted on July 21 for the coasts of Baja California del Sur before it was upgraded into a warning the same day. The watch was discontinued two days after.
Dora caused strong rip currents and rain
to Southwest Mexico's coastline. In Acapulco, Mexico, police advised swimmers about the dangers of the strong waves. Dora's storm surge
toppled a lighthouse
and swept about 60 thatch-roofed restaurants on the coast. In the Los Cabos Municipality, four elementary schools were converted into emergency shelter
s in preparation for any potential flooding. Boat tours and other tourism services in Los Cabos were suspended. As a remnant low, Dora enhanced a monsoon
southerly flow into Arizona
, producing showers across the state.
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...
during the 2011 Pacific hurricane season
2011 Pacific hurricane season
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...
. The fourth tropical depression, named storm, hurricane, and second major hurricane of the season, Dora developed a from a 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...
on July 18. Quickly intensifying, the new tropical depression became a tropical storm just three hours after formation. The storm began to explosively intensify
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...
on July 20, strengthening from a minimal hurricane to a category 4 in only 17 hours. Dora reached its peak strength during the early morning hours of July 21 with maximum sustained winds of 155 mph (250 km/h) and a minimum central pressure of 929 mbar, just 1 mile per hour short of Category 5 status. However, as quickly as Dora strengthened, it weakened. Cooler waters and 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...
began to weaken the hurricane, and by the end of July 22, Dora had already weakened to a tropical storm and soon dissipated on July 24, just west of the Baja California Peninsula.
Meteorological history
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. The tropical wave emerged into the Pacific Ocean
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...
on July 16 under favorable conditions for development. The system strengthened and became better organized the next few days as the once disorganized system of thunderstorms began to collect towards the center.
At 1500 UTC July 18, the disturbance was designated as Tropical Depression Four-E. By the time Four-E was designated, well-defined 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...
of convection and a tight inner wind field were observed. Despite modest northerly upper-level winds, the depression strengthened into a tropical storm, receiving the name Dora. Dora began to move west-northwestwards under the influence of a strong high pressure system
High pressure area
A high-pressure area is a region where the atmospheric pressure at the surface of the planet is greater than its surrounding environment. Winds within high-pressure areas flow outward due to the higher density air near their center and friction with land...
. Gradual intensification ensued, and an eye began to form in Dora the next day. Late on July 19, Dora attained hurricane status with hurricane-force winds extending up to 35 miles (55 km) from the center as the eyewall contracted. Dora continued to gradually strengthen early on July 20. However, in the afternoon, Hurricane Dora rapidly intensified
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...
to a major hurricane, the second of the season with winds of 115 miles per hour (185.1 km/h) and higher gusts. The inner core solidified and eyewall mesovortices were hinted. Dora continued to quickly intensify, becoming a category 4 hurricane just hours later with maximum wind speeds of 135 miles per hour (217.3 km/h) and a hurricane-force wind field extending to a 40 miles (64.4 km) radius. The next day, Dora began to take on the appearance of an 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...
, with an eye similar to those seen in Hurricane Isabel. Continuing to rapidly intensify, Hurricane Dora attained peak intensity later on July 21 with winds of 155 miles per hour (249.4 km/h) and a central minimum pressure of 929 mbar (hPa; 27.43 inHg) while 445 miles (715 km) south-southeast of Cabo San Lucas, Mexico.
However, Dora began to traverse colder waters and encountered unfavorable wind shear. The eye abruptly dissipated and convection became much less organized. Within 12 hours, Dora already weakened into a category 3 hurricane. On July 22, the low-level circulation center became exposed as convection shifted to the southern semicircle
Semicircle
In mathematics , a semicircle is a two-dimensional geometric shape that forms half of a circle. Being half of a circle's 360°, the arc of a semicircle always measures 180° or a half turn...
. Dora continued to be sheared by strong northwesterly wind shear as it quickly weakened. Dora's satellite signature deteriorated along with much of its convection. The hurricane was downgraded to a tropical storm late on July 22 as it moved into hostile atmospheric conditions and cooler water. Based on data from Hurricane Hunters
Hurricane Hunters
The Hurricane Hunters are aircraft that fly into tropical cyclones in the North Atlantic Ocean and Northeastern Pacific Ocean for the specific purpose of directly measuring weather data in and around those storms. In the United States, the Air Force, Navy, and NOAA units have all participated in...
, the NHC issued its last advisory for Dora on the evening of July 24. 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...
.
Preparations and impact
On July 19, a tropical storm watch was issued for portions of the coast of Southwestern Mexico as Dora strengthened into a category one hurricane. The watch was continued until late on July 20, after Dora moved further away from the mainlandMainland
Mainland is a name given to a large landmass in a region , or to the largest of a group of islands in an archipelago. Sometimes its residents are called "Mainlanders"...
. Another watch was soon posted on July 21 for the coasts of Baja California del Sur before it was upgraded into a warning the same day. The watch was discontinued two days after.
Dora caused strong rip currents and 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...
to Southwest Mexico's coastline. In Acapulco, Mexico, police advised swimmers about the dangers of the strong waves. Dora's storm surge
Storm surge
A storm surge is an offshore rise of water associated with a low pressure weather system, typically tropical cyclones and strong extratropical cyclones. Storm surges are caused primarily by high winds pushing on the ocean's surface. The wind causes the water to pile up higher than the ordinary sea...
toppled a lighthouse
Lighthouse
A lighthouse is a tower, building, or other type of structure designed to emit light from a system of lamps and lenses or, in older times, from a fire, and used as an aid to navigation for maritime pilots at sea or on inland waterways....
and swept about 60 thatch-roofed restaurants on the coast. In the Los Cabos Municipality, four elementary schools were converted into emergency shelter
Emergency shelter
Emergency shelters are places for people to live temporarily when they can't live in their previous residence, similar to homeless shelters. The main difference is that an emergency shelter typically specializes in people fleeing a specific type of situation, such as natural or man-made disasters,...
s in preparation for any potential flooding. Boat tours and other tourism services in Los Cabos were suspended. As a remnant low, Dora enhanced a monsoon
Monsoon
Monsoon is traditionally defined as a seasonal reversing wind accompanied by corresponding changes in precipitation, but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea...
southerly flow into 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...
, producing showers across the state.
See also
- Timeline of the 2011 Pacific hurricane seasonTimeline of the 2011 Pacific hurricane seasonThe 2011 Pacific hurricane season officially started on May 15, 2011 in the eastern Pacific, designated as the area east of 140°W, and on June 1, 2011 in the central Pacific, which is between the International Date Line and 140°W, and lasted until November 30, 2011. These dates typically limit the...
- 2011 Pacific hurricane season2011 Pacific hurricane seasonThe 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...
- Other storms of the same name