Tropical Storm Chantal taking rare early-season path

Tropical Storm Chantal is churning through the Lesser Antilles islands and possibly heading toward the East Coast, a path that is more common in the heart of hurricane season than in early July.

Not only that, but the storm is a bit "early" to begin with: The third named storm of the Atlantic hurricane season comes, on average, around Aug. 13.

As of Tuesday morning, Chantal was about 85 miles east of St. Lucia with maximum sustained winds of 50 mph. The National Hurricane Center's forecast cone takes it across Hispaniola, through the Bahamas and a few hundred miles east of Florida's Atlantic coast by next weekend.

AccuWeather.com's Henry Margusity suggests the storm could meet some unfavorable conditions, including dry air and high wind shear, in which wind speeds vary at different altitudes and inhibit storm development. But if Chantal survives through the weekend, it could cross Florida and move through the Gulf of Mexico, Margusity writes.

Of course, the track is likely to shift by then, even though improved forecasting has meant the hurricane center now takes its forecast cone out five days -- two days more than it did last season and in years past. It's unclear how weather systems over the eastern U.S. will affect Chantal's trajectory, whether pulling it out to sea or toward coastline.

An area of high pressure over the eastern United States could act as a blockade, steering the storm back west toward the U.S. coastline, said Paul Walker, a senior meteorologist with AccuWeather. But if that pressure is slow to build, it could allow the storm to curve out to sea.

Before that, the storm has to survive a pass over the mountains of Hispaniola, some of which are 10,000 feet high, he added.

"All of the options are there right now," Walker said.

Still, the storm is already in rare territory for being so early in the season, explains the Weather Underground's Jeff Masters:

"Formation of a tropical storm east of the Lesser Antilles Islands in early July from an African tropical wave is an uncommon occurrence. Since Atlantic hurricane records began in 1851, there have been only thirteen tropical depressions or tropical storms that have formed July 15 or earlier that have passed through the Lesser Antilles, an average of one early-season tropical cyclone every thirteen years."

Masters adds that two of those storms occurred in the record-setting hurricane season of 2005.

Chantal could indicate another active season ahead -- Colorado State University's Tropical Meteorology Project suggest as much, saying that named Atlantic storms are otherwise rare in June and July.