Tropical Storm Helene was a moderate tropical storm which affected the southern Caribbean and Central America in mid-August 2012. The seventh

tropical depression A tropical cyclone is a rapidly rotating storm, storm system characterized by a Low-pressure area, low-pressure center, a closed low-level atmospheric circulation, Beaufort scale, strong winds, and a spiral arrangement of thunderstorms tha ...

and eighth named storm of the

2012 Atlantic hurricane season The 2012 Atlantic hurricane season was the final year in a consecutive string of three very active seasons since 2010, with 19 tropical storms; although many of the storms were weak and short-lived. The 2012 season was also a costly season i ...

, Helene was monitored as a

tropical wave A tropical wave (also called easterly wave, tropical easterly wave, and African easterly wave), in and around the Atlantic Ocean, is a type of atmospheric trough, an elongated area of relatively low air pressure, oriented north to south, which ...

that exited the west coast of the African continent on August 5. It gradually moved westward and became a tropical depression east of the

Lesser Antilles The Lesser Antilles ( es, link=no, Antillas Menores; french: link=no, Petites Antilles; pap, Antias Menor; nl, Kleine Antillen) are a group of islands in the Caribbean Sea. Most of them are part of a long, partially volcanic island arc bet ...

four days later. However, unfavorable conditions initially prevented it from developing, which led to its initial degeneration to a remnant low as it traversed the Caribbean Sea.

Meteorological history

Tropical Storm Helene originated from a

, with an accompanying area of low pressure, which moved off the west coast of

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

on August 5. The wave traversed westward with some cyclonic rotation occurring in the middle levels of the

atmosphere An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. ...

and a large area of

convection Convection is single or multiphase fluid flow that occurs spontaneously due to the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity (see buoyancy). When the cause of the c ...

. Early on August 7, the

National Hurricane Center The National Hurricane Center (NHC) is the division of the United States' NOAA/ National Weather Service responsible for tracking and predicting tropical weather systems between the Prime Meridian and the 140th meridian west poleward to the 3 ...

(NHC) began to monitor the disturbance, noting the possibility of

tropical cyclogenesis Tropical cyclogenesis is 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 temperate cyclogenesis occurs. Tropi ...

in the coming days. Although, the system was not expected to developed due to unfavorable upper-level

wind shear Wind shear (or windshear), sometimes referred to as wind gradient, is a difference in wind speed and/or direction over a relatively short distance in the atmosphere. Atmospheric wind shear is normally described as either vertical or horizon ...

. However, about 24 hours later, wind shear began to become more favorable for tropical cyclone development as the disturbance became better organized. By 18:00 UTC on August 9, thunderstorms became confined to the center of circulation, showing signs of further organization. This promoted the NHC to upgrade the disturbance into ''Tropical Depression Seven'', while it was located roughly midway between

Cape Verde , national_anthem = () , official_languages = Portuguese , national_languages = Cape Verdean Creole , capital = Praia , coordinates = , largest_city = capital , demonym ...

and the

. During the next day, the depression changed little despite being within a favorable environment, moving westward due to a subtropical ridge to its north. Despite an increase of convective activity on August 11, the system remained disorganized due to strong southwesterly wind shear, with its swift westward motion making it uncertain if a closed circulation still remained. By 12:00 UTC that day, Hurricane Hunters Reconnaissance aircraft failed to discover a well-defined or persistent circulation, signifying the depression's reabsorption into its parent wave. The NHC continued to monitor the remnants of Seven as they crossed the

, shortly after dissipation. The remnants entered the eastern

Caribbean Sea The Caribbean Sea ( es, Mar Caribe; french: Mer des Caraïbes; ht, Lanmè Karayib; jam, Kiaribiyan Sii; nl, Caraïbische Zee; pap, Laman Karibe) is a sea of the Atlantic Ocean in the tropics of the Western Hemisphere. It is bounded by Mexico ...

on August 12 and produced a disorganized area of convection that stretched from the ABC Islands to the Leeward Islands. However, environmental conditions in the region remained unfavorable for regeneration. The next day, however, convection associated with the wave began to diminish, though started wind shear to become more favorable, land interaction with

Central America Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...

halted further development. By August 14, shower and thunderstorm activity returned to normal, however, further organization was halted as the wave crossed through northeastern

Nicaragua Nicaragua (; ), officially the Republic of Nicaragua (), is the largest Sovereign state, country in Central America, bordered by Honduras to the north, the Caribbean Sea, Caribbean to the east, Costa Rica to the south, and the Pacific Ocean to ...

and eastern Honduras the following day. While over Central America, the disturbance spawned an area of low pressure which moved into the

Bay of Campeche The Bay of Campeche ( es, Bahía de Campeche), or Campeche Sound, is a bight in the southern area of the Gulf of Mexico, forming the north side of the Isthmus of Tehuantepec. It is surrounded on three sides by the Mexican states of Campeche, Tab ...

, late on August 16. Around this time, convective activity associated with the wave began to organize within an area favorable for tropical cyclogenesis. By 12:00 UTC the next day, surface observations and radar data depicted a better-defined circulation, with the NHC estimating the regeneration of Tropical Depression Seven occurred around this time. Just six hours later, Hurricane Hunters Reconnaissance aircraft found peak-level winds of around 45 mph (75 km/h) and a minimum pressure of around 1004 mbar (29.65

inHg Inch of mercury (inHg and ″Hg) is a non- SI unit of measurement for pressure. It is used for barometric pressure in weather reports, refrigeration and aviation in the United States. It is the pressure exerted by a column of mercury in heigh ...

), with the NHC upgrading the system into ''Tropical Storm Helene'' as the storm reached its peak intensity. However, the storm still remained disorganized with convection being displaced west of the center, while winds were being enhanced by the displaced convection and

topography Topography is the study of the forms and features of land surfaces. The topography of an area may refer to the land forms and features themselves, or a description or depiction in maps. Topography is a field of geoscience and planetary s ...

. Almost immediately, Helene began to weaken while drifting gradually west-northwestward towards the eastern coastline of

Mexico Mexico ( Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guate ...

. Early on August 18, satellite observations depicted a deteriorating cloud pattern, despite a well-defined circulation and environmental conditions conducive for development. Around 12:00 UTC that day, Helene was downgraded into a tropical depression and crossed the Mexican coastline near

Tampico Tampico is a city and port in the southeastern part of the state of Tamaulipas, Mexico. It is located on the north bank of the Pánuco River, about inland from the Gulf of Mexico, and directly north of the state of Veracruz. Tampico is the fifth ...

Tamaulipas Tamaulipas (), officially the Free and Sovereign State of Tamaulipas ( es, Estado Libre y Soberano de Tamaulipas), is a state in the northeast region of Mexico; one of the 31 states which, along with Mexico City, comprise the 32 Federal Entiti ...

. Despite the center moving inland, a new burst of deep convection formed near the center likely due to upslope flow from the

Sierra Madre Occidental The Sierra Madre Occidental is a major mountain range system of the North American Cordillera, that runs northwest–southeast through northwestern and western Mexico, and along the Gulf of California. The Sierra Madre is part of the American ...

, with convective banding features offshore remaining potent. At 0:00 UTC on August 19, Helene degenerated into a broad area of low pressure, with convective activity now degraded to only a few showers. Just six hours later, the remnants of Helene dissipated.

Preparations and impact

Caribbean

The remnants of Tropical Depression Seven caused severe flooding in

Trinidad Trinidad is the larger and more populous of the two major islands of Trinidad and Tobago. The island lies off the northeastern coast of Venezuela and sits on the continental shelf of South America. It is often referred to as the southernmos ...

on August 11. Flooding damaged retaining walls at 50 homes in Diego Martin, which was cutoff by floodwaters. A total of 12 homes were destroyed the floods. Heavy rainfall and mudslides were reported across the island, which resulted in the deaths of two people. Major damage was reported to infrastructure, including loss of utility assets and damage to roadways. Following the floods, 1,112 members of the Diego Martin Regional Corporation were deployed to assist in relief efforts. The regional corporation reported that 225 people had asked for assistance. Damage from the floods totaled to around $17 million (2012 USD). A total of 12 people had to find refuge in shelters. The remnants of Seven caused a 1 in 50 year event in Diego Martin, according to local corporations. In Dominica, over 4 inches (101.6 mm) of precipitation fell in the Layou-

Roseau Roseau ( Dominican Creole: ''Wozo'') is the capital and largest city of Dominica, with a population of 14,725 as of 2011. It is a small and compact urban settlement, in the Saint George parish and surrounded by the Caribbean Sea, the Roseau ...

area within a three hour period, causing minor flooding. Some areas lost connection to internet, including the Office of Disaster Management (ODM) building. Flooding in

Castle Bruce Castle Bruce is a village on the east coast of Dominica Dominica ( or ; Kalinago: ; french: Dominique; Dominican Creole French: ), officially the Commonwealth of Dominica, is an island country in the Caribbean. The capital, Roseau, is loca ...

resulted in the drowning deaths of 14 livestock. Minimal pockets of flooding were reported in

Saint Lucia Saint Lucia ( acf, Sent Lisi, french: Sainte-Lucie) is an island country of the West Indies in the eastern Caribbean. The island was previously called Iouanalao and later Hewanorra, names given by the native Arawaks and Caribs, two Amerindi ...

, but floodwaters rapidly receded. The remnants of Seven brought tropical storm-force wind gusts and torrential rainfall to

while crossing between August 14–15. The system also brought increased moisture and shower activity to

Belize Belize (; bzj, Bileez) is a Caribbean and Central American country on the northeastern coast of Central America. It is bordered by Mexico to the north, the Caribbean Sea to the east, and Guatemala to the west and south. It also shares a wa ...

, with rain peaking at around 0.75 inches (19.05 mm) in northern parts of the country.

Mexico

Upon reformation, the Government of

issued a Tropical Storm Warning from Barra de Naulta,

Veracruz Veracruz (), formally Veracruz de Ignacio de la Llave (), officially the Free and Sovereign State of Veracruz de Ignacio de la Llave ( es, Estado Libre y Soberano de Veracruz de Ignacio de la Llave), is one of the 31 states which, along with Me ...

to La Cruz,

. This was discontinued as Helene moved inland and weakened, at 15:00 UTC on August 18. As Helene approached land, the Sistema Nacional de Protección Civil (SINAPROC) declared a red alert for southern Tamaulipas and northern Veracruz. Personnel from civil protection programs were stationed in the municipalities of

Pueblo Viejo In the Southwestern United States, Pueblo (capitalized) refers to the Native tribes of Puebloans having fixed-location communities with permanent buildings which also are called pueblos (lowercased). The Spanish explorers of northern New Spain ...

Tampico Alto Tampico Alto is a town in the Mexican state The states of Mexico are first-level administrative territorial entities of the country of Mexico, which is officially named Mexico, United Mexican States. There are 32 federal entities in Mexico (31 ...

, and Pánuco to monitor weather conditions and provide aid to residents. Ports in northern and central Veracruz prohibited non-essential transportation.

Notes

References

External links

{{DEFAULTSORT:Helene (2012) Helene Helene Atlantic tropical storms Hurricanes in the Windward Islands Hurricanes in Trinidad and Tobago Hurricanes in Dominica Hurricanes in Saint Lucia Hurricanes in Belize Atlantic hurricanes in Mexico