Tropical Storm Arlene forms in the Gulf of Mexico, expected to make landfall on Thursday

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Tropical Storm Arlene forms in the Gulf of Mexico, expected to make landfall on Thursday

2011-06-29 21:03:56 GMT+7 (ICT)

MIAMI (BNO NEWS) -- Tropical storm Arlene formed in the southwestern Gulf of Mexico on Tuesday evening, forecasters said, making it the first named storm of the Atlantic hurricane season. It is expected to make landfall in Mexico on Thursday.

Forecasters at the U.S. National Hurricane Center (NHC) have been following the weather system since Saturday when it emerged in the western Caribbean sea, producing cloudiness and scattered showers over parts of Honduras and Nicaragua. It slowly became better organized as it moved into the Gulf of Mexico, resulting in the formation of a tropical storm on Tuesday evening.

As of 7 a.m. CDT (1200 GMT) on Wednesday, the center of Arlene was located about 175 miles (280 kilometers) east of Tampico, a city in the Mexican state of Tamaulipas. It is moving toward the west-northwest at a speed of 8 miles (13 kilometers) per hour, and a turn toward the west is expected later on Wednesday.

Maximum winds of Arlene are near 40 miles (65 kilometers) per hour, with higher gusts. "Upper-level cloud motions suggest that the shear is decreasing, and given an increasingly favorable environment, it seems like it is only a matter of time before Arlene strengthens," said NHC senior hurricane specialist Michael Brennan.

And although Arlene is expected to strengthen, it is unlikely that it will reach hurricane strength before making landfall. "The bulk of the intensity guidance shows the system as a moderate tropical storm before landfall, though the Hurricane Weather Research and Forecasting model (HWRF) has the system briefly as a hurricane," said Brennan. "Given the large size of Arlene and the lack of any inner core features, hurricane strength appears unlikely."

Tropical storm force winds extend outward up to 115 miles (185 kilometers) from the center, meaning tropical storm conditions are expected to reach the northeastern Mexico coast by Wednesday evening, well before the storm makes landfall on Thursday.

"Given the large size of the circulation of Arlene, one should not focus on the exact forecast track, as impacts will likely be felt over a large portion of northeastern Mexico well away from the center," Brennan added. As a result, a tropical storm warning has been issued for the northeastern Mexico coast from Barra de Nautla in Veracruz to Bahia Algodones in Tamaulipas.

"Tropical storm conditions are expected to reach the coast within the warning area by this evening, which could make outside preparations difficult or dangerous," said NHC senior hurricane specialist Jack Beven.

Beven said Arlene is expected to produce total rainfall accumulations of 4 to 8 inches (10 to 20 centimeters) over the Mexican states of Tamaulipas, Varacruz, and eastern San Luis Potosi. Over mountainous terrain, isolated maximum amounts of up to 15 inches (38 centimeters) is possible, which could result in dangerous flash floods and mudslides.

"A storm surge will raise water levels by as much as 1 to 2 feet (30 to 60 centimeters) above normal tide levels along the immediate coast near and to the north of where the center makes landfall," Beven added. "Near the coast, the surge could be accompanied by large and destructive waves."

Arlene is the first named storm of the 2011 Atlantic hurricane season. According to figures released in May, NOAA's Climate Prediction Center is expecting an above-normal hurricane season in the Atlantic this year. The outlook calls for 12 to 18 named storms, with six to ten becoming hurricanes and three to six expected to become a major hurricane (category 3 or higher).

An average Atlantic hurricane season produces 11 named storms, with six becoming hurricanes and two becoming major hurricanes. The Atlantic hurricane season runs from June 1 through November 30, with peak activity in September.

In March, an extremely rare subtropical cyclone formed in the South Atlantic near southeastern Brazil. Arani, as it was called, briefly made landfall in Brazil but caused no casualties.

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