Tropical Storm Georgette (2010) - AbsoluteAstronomy.com

Tropical Storm Georgette was a short-lived tropical storm that struck the 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...

in September 2010. Georgette originated from an area of disturbed weather over the eastern Pacific on September 20. The next day, the system was upgraded into a tropical storm

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...

a short distance south of Baja California Sur. As the storm moved over the peninsula, it weakened to a topical depression. It continued north and as such made landfall on mainland Mexico on September 22. Georgette dissipated early the next day while located inland over Sonora

Sonora

Sonora officially Estado Libre y Soberano de Sonora is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided into 72 municipalities; the capital city is Hermosillo....

. Although officials noted the threat for heavy rainfall

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...

across northwest Mexico and Baja California, damage was minimal and no deaths were reported.

Meteorological history

The origins of Tropical Storm Georgette were 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...

that moved off the west 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 September 1. Lacking organization, the wave was difficult to track as it moved across the Atlantic basin. 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...

eventually increased on September 7, as the system approached the Lesser Antilles

Lesser Antilles

The Lesser Antilles are a long, partly volcanic island arc in the Western Hemisphere. Most of its islands form the eastern boundary of the Caribbean Sea with the Atlantic Ocean, with the remainder located in the southern Caribbean just north of South America...

. On September 14, Hurricane Karl developed from the northern portion of the system over the western 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....

; however, the southern portion of the wave crossed northern 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 September 17. The area of disturbed weather was first mentioned on the National Hurricane Center (NHC) around that time, but signification development was initially not anticipated. 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...

was forecast to decrease slightly, however, and based on this the NHC gave the system a medium chance of undergoing tropical cyclogenesis

Tropical cyclogenesis

Tropical cyclogenesis is the term that describes the development and strengthening of a tropical cyclone in the atmosphere. The mechanisms through which tropical cyclogenesis occurs are distinctly different from those through which mid-latitude cyclogenesis occurs...

during the next two days.

Gradual development took place as convection consolidated around the center of circulation

Atmospheric circulation

Atmospheric circulation is the large-scale movement of air, and the means by which thermal energy is distributed on the surface of the Earth....

while located west of Sonora

Sonora

. During the afternoon of September 20, an area of low pressure

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...

developed within the system, prompting the NHC to classify it as a tropical depression. At this time, the depression was situated roughly 240 mi (390 km) south-southeast of Cabo San Lucas

Cabo San Lucas

Cabo San Lucas , commonly called Cabo, is a city at the southern tip of the Baja California peninsula, in the municipality of Los Cabos in the Mexican state of Baja California Sur. As of the 2010 census, the population was 68,463 people...

. Situated along the western edge of a subtropical ridge

Subtropical ridge

The subtropical ridge is a significant belt of high pressure situated around the latitudes of 30°N in the Northern Hemisphere and 30°S in the Southern Hemisphere. It is characterized by mostly calm winds, which acts to reduce air quality under its axis by causing fog overnight, and haze during...

, the system was steered towards the north-northwest throughout its existence.

Within hours of becoming a depression on September 20, strong wind shear caused convection to diminish. However, data from an ASCAT scatterometer

Scatterometer

A radar scatterometer is designed to determine the normalized radar cross section of the surface. Scatterometers operate by transmitting a pulse of microwave energy towards the Earth's surface and measuring the reflected energy. A separate measurement of the noise-only power is made and...

pass revealed that the system attained gale-force winds, resulting in the depression being upgraded to a tropical storm on 0000 UTC September 21. Operationally, the first advisory on storm was not issued until 1200 UTC, where it was named Georgette. Meanwhile, thunderstorm activity increased near the center of the storm. Little change took place throughout the day as the storm approached Baja California Sur

Baja California Sur

. Around 1800 UTC

Coordinated Universal Time

Coordinated Universal Time is the primary time standard by which the world regulates clocks and time. It is one of several closely related successors to Greenwich Mean Time. Computer servers, online services and other entities that rely on having a universally accepted time use UTC for that purpose...

, Georgette made 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...

near San Jose del Cabo with winds of 40 mph (65 km/h). Additionally, a barometric pressure of 999 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...

; 29.5 inHg) was measured. Shortly before entering 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...

, Georgette weakened to a tropical depression. Maintaining winds of 35 mph (55 km/h), the storm later made a second landfall near San Carlos in Sonora

Sonora

. Shortly after moving inland, the low-level circulation dissipated over the mountains of western Mexico.

Preparations and Impact

Prior to the arrival of Georgette, the Mexican government issued a tropical storm warning for extreme southern Baja California Sur

Baja California Sur

., but was dropped when Georgette moved inland. Officials warned rural areas in Baja California Sur of heavy rain

Rain

and high 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...

. Forecasters at the NHC noted the potential for up to 10 in (25 mm) of rainfall, especially over the higher terrain. The forecasters also noted potential for deadly flood

Flood

A flood is an overflow of an expanse of water that submerges land. The EU Floods directive defines a flood as a temporary covering by water of land not normally covered by water...

ing and mudslides. Officials evacuated over 1,000 families from floodplains and opened four shelters in Los Cabos

Los Cabos

Los Cabos is a municipality located at the southern tip of Mexico's Baja California Peninsula, in the state of Baja California Sur. It encompasses the towns of Cabo San Lucas and San José del Cabo , as well as the Resort Corridor that lies between the two...

.

In Sonora

Sonora

, the state's civil protection committee placed the south portion of the state under an "orange" alert, and a "red" alert soon after; the alert was lifted that same evening, after Georgette moved inland. A total of 52 shelters were opened in the Cajeme municipality

Cajeme

Cajeme is one of the municipalities of the northwestern state of Sonora, Mexico. Its capital is Ciudad Obregón. It is named after Cajemé, a Yaqui leader...

. In Guaymas, 300 people from the city and surrounding areas were placed in shelters; 250 more people sought shelter from Georgette in Empalme. Schools in Bahía Kino

Bahía Kino

Bahía Kino is a town in the Mexican state of Sonora, on the Sea of Cortez Gulf of California; it was named after Eusebio Kino. The name also applies to the adjacent bay between Tiburón Island and Punta San Nicolás, Sonora...

and coastal areas of the Hermosillo Municipality suspended classes as a precaution. Classes resumed statewide on September 23.

Georgette caused the heaviest rains on Baja California Sur in the last 15 years, leaving many people homeless. Georgette also produced high waves. The tropical cyclone worsened 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...

's flooding problem which started when Hurricane Karl made landfall several days earlier. A peak rainfall total of 5.9 in (149.9 mm) fell in Todos Santos.Throughout Sonora, rainfall up to 4.7 in (119.4 mm) triggered flooding that damaged 220 homes. Georgette caused 2.61 in (66.3 mm) of rainfall in Guaymas Flooding was reported in several places (Empalme, Etchojoa, Navojoa, Guaymas, Los Mochis), causing 500,000 people to be evacuated. Heavy runoff caused inflows of 18000 ft3/s into El Novillo Dam, forcing the Comisión Nacional del Agua, the local water authorities, to release water from the dam.

Meteorological history

Preparations and Impact

See also