.gif)
Tropical Storm Douglas (2008)
Encyclopedia
Tropical Storm Douglas was the fourth named storm
of the 2008 Pacific hurricane season
. Douglas developed out of a tropical wave
that formed off the Africa
n coast on June 19 and traversed the Atlantic Ocean
. On June 27, the wave crossed Central America
and entered the Pacific Ocean
. On July 1, the storm developed into Tropical Depression Four-E while located 245 nmi (453.7 km) southwest of Manzanillo, Mexico as it traveled to the northwest. Despite being dislocated from most of the convection
by strong wind shear
, the depression gradually became better organized and on the afternoon July 2, the depression was upgraded to Tropical Storm Douglas. Upon the upgrade, Douglas reached its peak intensity of 40 mph (65 km) and minimum pressure of 1003 mbar (hPa; 29.63 inHg). Douglas weakened to a tropical depression overnight on July 3. The depression became devoid of convection shortly after and was further downgraded to a remnant low-pressure area
on the morning of July 4 as it turned towards the west. The remnant low continued to weaken and completely dissipated on July 6.
exited the coast of Africa
on June 19. The wave remained poorly organized as it traversed the Atlantic
and entered the Pacific Ocean
on June 27. On June 28, deep convection
developed and a broad low-level circulation developed along the wave while located a few hundred miles south of the Gulf of Tehuantepec
. The low traveled to the northwest and began to develop a well-defined circulation. The low was upgraded to a tropical depression early on July 1 while located 245 nmi (453.7 km) southwest of Manzanillo, Mexico.
The center of the depression was elongated as it entered an area of strong northeasterly wind shear
. The shear caused the low to become displaced to the north of the convection. Despite the shear, deep convection developed in developing bands in the south and western portions of the storm. The depression continued to become better organized and on July 2, it was upgraded to Tropical Storm Douglas. However, the center of circulation remained located to the northeast of the deepest convection. During the late morning hours, the cloud tops began to warm, signifying that the system was weakening. A microwave satellite overpass earlier in the day revealed that the storm still had a broad circulation. The structure of Douglas continued to deteriorate throughout the day and was barely a tropical storm as satellite estimates put the intensity at 35 mph (55 km/h) to 40 mph (65 km/h).
On the morning of July 3, wind shear dislocated the center of Douglas even further to the northeast of the deepest convection and the storm began to move over cooler waters. Forecasts showed a rapid degeneration into a remnant low as the storm moved closer to a more hostile environment. By the late morning, Douglas was downgraded to a tropical depression as all the deep convection associated with the system dissipated, leaving only mid- to low-level convection. However, in the post-season analysis, it was determined that Douglas had remained a tropical storm through the early afternoon, six hours later than the operational advisories. By the early afternoon, Douglas was devoid of almost all convection and was a swirl of clouds. Douglas degenerated into a remnant low early on the morning of July 4. The remnant low moved towards the west for two days before dissipating out over open waters due to the effects of cool waters and strong wind shear.
, Colima
, Jalisco
, Nayarit
, and Baja California Sur
. Due to the proximity to land, outer rain bands associated with Douglas produced tropical storm force winds in Manzanillo, Mexico. Minor flood damage was reported along the coastline in Colima, Jalisco, and Nayarit. On July 2, a ship located to the southwest of the center reported a sustained wind of 30 mph (50 km/h). Moisture associated with Douglas produced light rain over parts of Baja California Sur. Thunderstorm
s developed near Todos los Santos, producing isolated heavy rain.
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...
of the 2008 Pacific hurricane season
2008 Pacific hurricane season
The 2008 Pacific hurricane season was an event in the annual cycle of tropical cyclone formation. It officially started May 15, 2008 in the eastern Pacific, started on June 1, 2008 in the central Pacific, and lasted until November 30, 2008....
. Douglas developed out of 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...
that formed off the Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
n coast on June 19 and traversed the Atlantic Ocean
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
. On June 27, the wave crossed Central America
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
and entered 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 1, the storm developed into Tropical Depression Four-E while located 245 nmi (453.7 km) southwest of Manzanillo, Mexico as it traveled to the northwest. Despite being dislocated from most of the 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...
by strong wind shear
Wind shear
Wind shear, sometimes referred to as windshear or wind gradient, is a difference in wind speed and direction over a relatively short distance in the atmosphere...
, the depression gradually became better organized and on the afternoon July 2, the depression was upgraded to Tropical Storm Douglas. Upon the upgrade, Douglas reached its peak intensity of 40 mph (65 km) and minimum pressure of 1003 mbar (hPa; 29.63 inHg). Douglas weakened to a tropical depression overnight on July 3. The depression became devoid of convection shortly after and was further downgraded to a remnant low-pressure area
Low pressure area
A low-pressure area, or "low", is a region where the atmospheric pressure at sea level is below that of surrounding locations. Low-pressure systems form under areas of wind divergence which occur in upper levels of the troposphere. The formation process of a low-pressure area is known as...
on the morning of July 4 as it turned towards the west. The remnant low continued to weaken and completely dissipated on July 6.
Meteorological history
A disorganized 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...
exited the coast of Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
on June 19. The wave remained poorly organized as it traversed the Atlantic
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
and entered 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 June 27. On June 28, 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...
developed and a broad low-level circulation developed along the wave while located a few hundred miles south 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...
. The low traveled to the northwest and began to develop a well-defined circulation. The low was upgraded to a tropical depression early on July 1 while located 245 nmi (453.7 km) southwest of Manzanillo, Mexico.
The center of the depression was elongated as it entered an area of strong northeasterly wind shear
Wind shear
Wind shear, sometimes referred to as windshear or wind gradient, is a difference in wind speed and direction over a relatively short distance in the atmosphere...
. The shear caused the low to become displaced to the north of the convection. Despite the shear, deep convection developed in developing bands in the south and western portions of the storm. The depression continued to become better organized and on July 2, it was upgraded to Tropical Storm Douglas. However, the center of circulation remained located to the northeast of the deepest convection. During the late morning hours, the cloud tops began to warm, signifying that the system was weakening. A microwave satellite overpass earlier in the day revealed that the storm still had a broad circulation. The structure of Douglas continued to deteriorate throughout the day and was barely a tropical storm as satellite estimates put the intensity at 35 mph (55 km/h) to 40 mph (65 km/h).
On the morning of July 3, wind shear dislocated the center of Douglas even further to the northeast of the deepest convection and the storm began to move over cooler waters. Forecasts showed a rapid degeneration into a remnant low as the storm moved closer to a more hostile environment. By the late morning, Douglas was downgraded to a tropical depression as all the deep convection associated with the system dissipated, leaving only mid- to low-level convection. However, in the post-season analysis, it was determined that Douglas had remained a tropical storm through the early afternoon, six hours later than the operational advisories. By the early afternoon, Douglas was devoid of almost all convection and was a swirl of clouds. Douglas degenerated into a remnant low early on the morning of July 4. The remnant low moved towards the west for two days before dissipating out over open waters due to the effects of cool waters and strong wind shear.
Impact
On July 2, a blue alert was declared for Socorro IslandSocorro Island
Socorro Island is a small volcanic island in the Revillagigedo Islands, a Mexican possession lying some 600 kilometers off the country's western coast at 18°48'N, 110°59'W. The size is 16.5 by 11.5 km, with an area of 132 km².- Geology :...
, 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....
, Jalisco
Jalisco
Jalisco officially Estado Libre y Soberano de Jalisco is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is located in Western Mexico and divided in 125 municipalities and its capital city is Guadalajara.It is one of the more important states...
, Nayarit
Nayarit
Nayarit officially Estado Libre y Soberano de Nayarit is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 20 municipalities and its capital city is Tepic.It is located in Western Mexico...
, and Baja California Sur
Baja California Sur
Baja California Sur , is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. Before becoming a state on October 8, 1974, the area was known as the South Territory of Baja California. It has an area of , or 3.57% of the land mass of Mexico and comprises...
. Due to the proximity to land, outer rain bands associated with Douglas produced tropical storm force winds in Manzanillo, Mexico. Minor flood damage was reported along the coastline in Colima, Jalisco, and Nayarit. On July 2, a ship located to the southwest of the center reported a sustained wind of 30 mph (50 km/h). Moisture associated with Douglas produced light rain over parts of Baja California Sur. Thunderstorm
Thunderstorm
A thunderstorm, also known as an electrical storm, a lightning storm, thundershower or simply a storm is a form of weather characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere known as thunder. The meteorologically assigned cloud type associated with the...
s developed near Todos los Santos, producing isolated heavy rain.