Tropical Storm Rachel (1990)
Encyclopedia
Tropical Storm Rachel was only tropical cyclone
to make landfall
during the 1990 Pacific hurricane season
. The twenty-fourth tropical depression and eighteenth named storm
, Rachel developed
on September 27 from a tropical wave
southwest of mainland Mexico
. After becoming a tropical depression, the system tracked slowly southwestward and eventually curved northwestward. The depression intensified into a tropical storm after three days and was named Rachel by the National Hurricane Center
. Rachel continued to steadily strengthen, and peaked as a strong 65 mph (100 km/h) tropical storm on October 2. After attaining peak intensity, Rachel re-curved to make a landfall in southern Baja California Sur
and again in the Mexican Mainland on October 3. The storm produced heavy rainfall across northern Mexico and the Southwestern United States
. Thousands of people were left homeless and 18 fatalities were reported.
that moved off the west coast Africa in mid-September 1990. It moved westward into the Caribbean Sea
without significant development. Poorly organized, the wave entered the Eastern Pacific
on overnight September 22. The thunderstorm activity became more concentrated two days later. Dvorak classifications
, a technique used to estimate a tropical cyclone's intensity, began late September 25.
Early on September 27, the twenty-fourth tropical depression of the season had developed; however, operationally it was not warned upon until the system was located 540 mi (869 km) south of Baja California Sur
on September 30. Post-analysis later confirm that Rachel was already a minimal tropical storm by that time. Although convection
initially remained displaced from the center, Rachel steadily intensified. Early on September 30, the National Hurricane Center
(NHC) operationally upgraded the depression into Tropical Storm Rachel. While intensifying, an upper-level trough
over California
allowed Rachel to re-curve towards Mexico. On October 2, it reached its peak intensity of 65 mph (100 km/h) and a minimum pressure of 994 mbar
(hPa
; 29.35 inHg).
After maintaining its intensity for 24 hours, Rachel made landfall at peak intensity near the southern tip of Baja California Sur. Strong wind shear
prevented additional intensification, despite moving into the warm waters of the Gulf of California
. After weakening slightly, Rachel made a second landfall midway between Las Mochis and Culiacán
. Upon moving inland, the system rapidly weakened as the forward speed increased. Rachel dissipated several hours later on October 3. By that time, the winds had decreased to 30 mph (45 km/h). The remnants of Rachel entered the United States, and were last noted over Texas.
for southern Baja California Sur
, encompassing areas south of La Paz
on October 1. As Rachel moved closer to the area, the watch was replaced with a tropical storm warning
. In the mainland, a tropical storm watch was issued for the state of Sinaloa
south of Los Mmochis. Six hours later, the watches was replaced with a tropical storm warning. By the end of October 2, all the watches and warnings were discontinued.
The two highest rainfall totals were 9.85 in (250.2 mm) and 6.5 in (165.1 mm) at Santa Anita and San Jose Del Cobe, near the southern tip of Baja California Sur
. Two weather stations in Mexico reported barometric pressure of 1005 and 1006 mbar (hPa; 29.68 and 29.71 inHg) during the passage of Rachel. In all, precipitation was measured at 996 different places across the country. Throughout northern Mexico
, significant flooding was reported with the worst effects felt in the states of Nuevo Leon
, Coahuila
and Durango
. Thousands were homeless, and 18 people died. In Monterrey
, rescue workers freed dozens of trapped people.
The moisture associated with the Rachel and a cold front
produced rainfall in Arizona
, New Mexico
, and western Texas
, while it was located southwest of Baja California Sur. After Rachel had dropped heavy rains, a flash flood watch
was issued for several counties in New Mexico on October 1,where rainfall had reportedly been 2 in (50.8 mm) since the last day of September. Heavy rains fell on almost all of western Texas, and a flash flood warning had been issued after some areas experienced rainfall over 1 in (25.4 mm). With heavy rains falling in the western portion of Texas, some roads were washed out, especially in Big Bend National Park
and Lubbock
; several car accidents were also reported on the roads. Several locations in Texas measured at least 0.5 in (12.7 mm) of rain, and the highest amount of rainfall was 1.5 in (38.1 mm) in Lubbock.
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...
to make landfall
Landfall (meteorology)
Landfall is the event of a tropical cyclone or a waterspout coming onto land after being over water. When a waterspout makes landfall it is reclassified as a tornado, which can then cause damage inland...
during the 1990 Pacific hurricane season
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...
. The twenty-fourth tropical depression and eighteenth named storm
Tropical cyclone naming
Tropical cyclones have officially been named since 1945 and are named for a variety of reasons, which include to facilitate communications between forecasters and the public when forecasts, watches, and warnings are issued. Names also reduce confusion about what storm is being described, as more...
, Rachel developed
Tropical cyclogenesis
Tropical cyclogenesis is the term that describes the development and strengthening of a tropical cyclone in the atmosphere. The mechanisms through which tropical cyclogenesis occurs are distinctly different from those through which mid-latitude cyclogenesis occurs...
on September 27 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...
southwest of mainland 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...
. After becoming a tropical depression, the system tracked slowly southwestward and eventually curved northwestward. The depression intensified into a tropical storm after three days and was named Rachel by 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...
. Rachel continued to steadily strengthen, and peaked as a strong 65 mph (100 km/h) tropical storm on October 2. After attaining peak intensity, Rachel re-curved to make a landfall in southern 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...
and again in the Mexican Mainland on October 3. The storm produced heavy rainfall across northern Mexico and the Southwestern United States
Southwestern United States
The Southwestern United States is a region defined in different ways by different sources. Broad definitions include nearly a quarter of the United States, including Arizona, California, Colorado, Nevada, New Mexico, Oklahoma, Texas and Utah...
. Thousands of people were left homeless and 18 fatalities were reported.
Meteorological history
The origins of Rachel can be traced back to 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...
that moved off the west coast Africa in mid-September 1990. It moved westward into the 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....
without significant development. Poorly organized, the wave entered the Eastern Pacific
Pacific hurricane
A Pacific hurricane or tropical storm is a tropical cyclone that develops in the northeastern part of the Pacific Ocean. For organizational purposes, the northern Pacific Ocean is divided into three regions: the eastern, , central , and western...
on overnight September 22. The thunderstorm activity became more concentrated two days later. Dvorak classifications
Dvorak technique
The Dvorak technique is a widely used system to subjectively estimate tropical cyclone intensity based solely on visible and infrared satellite images. Several agencies issue Dvorak intensity numbers for cyclones of sufficient intensity...
, a technique used to estimate a tropical cyclone's intensity, began late September 25.
Early on September 27, the twenty-fourth tropical depression of the season had developed; however, operationally it was not warned upon until the system was located 540 mi (869 km) south of Baja California Sur
Baja California Sur
Baja California Sur , is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. Before becoming a state on October 8, 1974, the area was known as the South Territory of Baja California. It has an area of , or 3.57% of the land mass of Mexico and comprises...
on September 30. Post-analysis later confirm that Rachel was already a minimal tropical storm by that time. Although 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...
initially remained displaced from the center, Rachel steadily intensified. Early on September 30, 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) operationally upgraded the depression into Tropical Storm Rachel. While intensifying, an upper-level trough
Trough (meteorology)
A trough is an elongated region of relatively low atmospheric pressure, often associated with fronts.Unlike fronts, there is not a universal symbol for a trough on a weather chart. The weather charts in some countries or regions mark troughs by a line. In the United States, a trough may be marked...
over California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
allowed Rachel to re-curve towards Mexico. On October 2, it reached its peak intensity of 65 mph (100 km/h) and a minimum pressure of 994 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...
; 29.35 inHg).
After maintaining its intensity for 24 hours, Rachel made landfall at peak intensity near the southern tip of Baja California Sur. 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...
prevented additional intensification, despite moving into the warm waters of the Gulf of California
Gulf of California
The Gulf of California is a body of water that separates the Baja California Peninsula from the Mexican mainland...
. After weakening slightly, Rachel made a second landfall midway between Las Mochis and Culiacán
Culiacán
Culiacán is a city in northwestern Mexico, the largest city in the state of Sinaloa as well as its capital and capital of the municipality of Culiacán. With 675,773 inhabitants in the city , and 858,638 in the municipality, it is the largest city in the state of Sinaloa...
. Upon moving inland, the system rapidly weakened as the forward speed increased. Rachel dissipated several hours later on October 3. By that time, the winds had decreased to 30 mph (45 km/h). The remnants of Rachel entered the United States, and were last noted over Texas.
Preparations and impact
Prior to the arrival of Rachel, the Mexican government issued a tropical storm watchTropical cyclone warnings and watches
Warnings and watches are two levels of alert issued by national weather forecasting bodies to coastal areas threatened by the imminent approach of a tropical cyclone of tropical storm or hurricane intensity. They are notices to the local population and civil authorities to make appropriate...
for southern 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...
, encompassing areas south of La Paz
La Paz, Baja California Sur
La Paz is the capital city of the Mexican state of Baja California Sur and an important regional commercial center. The city had a 2010 census population of 215,178 persons, but its metropolitan population is somewhat larger because of surrounding towns like el Centenario, el Zacatal and San Pedro...
on October 1. As Rachel moved closer to the area, the watch was replaced with a tropical storm warning
Tropical cyclone warnings and watches
Warnings and watches are two levels of alert issued by national weather forecasting bodies to coastal areas threatened by the imminent approach of a tropical cyclone of tropical storm or hurricane intensity. They are notices to the local population and civil authorities to make appropriate...
. In the mainland, a tropical storm watch was issued for the state of Sinaloa
Sinaloa
Sinaloa officially Estado Libre y Soberano de Sinaloa is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 18 municipalities and its capital city is Culiacán Rosales....
south of Los Mmochis. Six hours later, the watches was replaced with a tropical storm warning. By the end of October 2, all the watches and warnings were discontinued.
The two highest rainfall totals were 9.85 in (250.2 mm) and 6.5 in (165.1 mm) at Santa Anita and San Jose Del Cobe, near the southern tip of Baja California Sur
Baja California Sur
Baja California Sur , is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. Before becoming a state on October 8, 1974, the area was known as the South Territory of Baja California. It has an area of , or 3.57% of the land mass of Mexico and comprises...
. Two weather stations in Mexico reported barometric pressure of 1005 and 1006 mbar (hPa; 29.68 and 29.71 inHg) during the passage of Rachel. In all, precipitation was measured at 996 different places across the country. Throughout northern 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...
, significant flooding was reported with the worst effects felt in the states of Nuevo Leon
Nuevo León
Nuevo León It is located in Northeastern Mexico. It is bordered by the states of Tamaulipas to the north and east, San Luis Potosí to the south, and Coahuila to the west. To the north, Nuevo León has a 15 kilometer stretch of the U.S.-Mexico border adjacent to the U.S...
, Coahuila
Coahuila
Coahuila, formally Coahuila de Zaragoza , officially Estado Libre y Soberano de Coahuila de Zaragoza is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico...
and Durango
Durango
Durango officially Estado Libre y Soberano de Durango is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. The state is located in Northwest Mexico. With a population of 1,632,934, it has Mexico's second-lowest population density, after Baja...
. Thousands were homeless, and 18 people died. In Monterrey
Monterrey
Monterrey , is the capital city of the northeastern state of Nuevo León in the country of Mexico. The city is anchor to the third-largest metropolitan area in Mexico and is ranked as the ninth-largest city in the nation. Monterrey serves as a commercial center in the north of the country and is the...
, rescue workers freed dozens of trapped people.
The moisture associated with the Rachel and a cold front
Cold front
A cold front is defined as the leading edge of a cooler mass of air, replacing a warmer mass of air.-Development of cold front:The cooler and denser air wedges under the less-dense warmer air, lifting it...
produced rainfall in Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...
, New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
, and western Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
, while it was located southwest of Baja California Sur. After Rachel had dropped heavy rains, a flash flood watch
Flash flood watch
A Flash flood watch is issued by the National Weather Service when conditions are favorable for flash flooding in flood-prone areas where grounds are already saturated from recent rains....
was issued for several counties in New Mexico on October 1,where rainfall had reportedly been 2 in (50.8 mm) since the last day of September. Heavy rains fell on almost all of western Texas, and a flash flood warning had been issued after some areas experienced rainfall over 1 in (25.4 mm). With heavy rains falling in the western portion of Texas, some roads were washed out, especially in Big Bend National Park
Big Bend National Park
Big Bend National Park is a national park located in the U.S. state of Texas. Big Bend has national significance as the largest protected area of Chihuahuan Desert topography and ecology in the United States, which includes more than 1,200 species of plants, more than 450 species of birds, 56...
and Lubbock
Lubbock, Texas
Lubbock is a city in and the county seat of Lubbock County, Texas, United States. The city is located in the northwestern part of the state, a region known historically as the Llano Estacado, and the home of Texas Tech University and Lubbock Christian University...
; several car accidents were also reported on the roads. Several locations in Texas measured at least 0.5 in (12.7 mm) of rain, and the highest amount of rainfall was 1.5 in (38.1 mm) in Lubbock.
See also
- 1990 Pacific hurricane season1990 Pacific hurricane seasonThe 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...