Tropical Storm Chantal forms in Atlantic

updated 5:07 p.m. ET July 31, 2007

MIAMI - Tropical Storm Chantal, the third named storm of the Atlantic hurricane season, was expected to weaken as it moved across the ocean on Tuesday but could still carry heavy rain to Canada, forecasters said.

The storm, which was not expected to threaten the United States, had maximum sustained wind of 50 mph and was centered about 235 miles south-southwest of Halifax, Nova Scotia, at 5 p.m. ET, according to the National Hurricane Center. It was moving northeast at about 26 mph.

Chantal was expected to be short-lived as a tropical storm, possibly weakening later Tuesday or Wednesday. Its rain could affect Newfoundland late Wednesday or early Thursday, but it will not be very strong, hurricane specialist Eric Blake said.

The first named storm of 2007 was Subtropical Storm Andrea, which formed in May. It was followed by Tropical Storm Barry, which formed on June 1, the first day of the official hurricane season.

Federal government forecasters said in late May that they expected a busier than normal Atlantic hurricane season, with 13 to 17 tropical storms and seven to 10 of those becoming hurricanes. A tropical storm has sustained wind of at least 39 mph and becomes a hurricane when sustained wind reaches 74 mph.

Last year, there were 10 tropical storms in the Atlantic and five hurricanes, none of which made landfall in the United States. It was a mild year in comparison with the devastating 2005 season, which set a record with 28 named storms, 15 of them hurricanes, including Hurricane Katrina.

The Atlantic hurricane season, which officially runs from June 1 to Nov. 30, averages 9.6 named storms, with 5.9 of them becoming hurricanes and 2.3 major hurricanes.

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