© REUTERS/NOAA/HandoutThis 1145Z GOES imagery shows Igor east of the northern Leeward Islands, and Tropical Storm Julia located south-southwest of the Cape Verde Islands.

Tropical Storm Julia grew in the far eastern Atlantic into the fifth hurricane of the storm season, while Hurricane Igor weakened slightly but remained a dangerous Category 4 storm, forecasters said on Tuesday.

Neither hurricane posed an immediate threat to land or energy interests, but Igor could threaten Bermuda by the weekend.

Julia reached hurricane status and then continued to strengthen, with top sustained winds of 85 miles per hour. It was about 355 miles west-northwest of the Cape Verde Islands at 11 a.m. EDT (1500 GMT), forecasters at the U.S. National Hurricane Center in Miami said.

Julia was moving west-northwest as a Category 1 hurricane on the five-step Saffir-Simpson scale of hurricane intensity, forecasters said. Its projected path would keep it out to sea.

Julia could strengthen slowly over the next two days, forecasters said. But as it gets closer to the more powerful Igor, strong upper-level winds flowing out from Igor could shear off and weaken Julia.

Farther west in the Atlantic, Hurricane Igor weakened slightly but still packed a punch, the center said.

Igor was about 710 miles east of the northern Leeward Islands with maximum sustained winds at 135 mph, the center said.

Igor had been moving west on Monday but curved to the west-northwest on Tuesday. It was expected to curl around to the north in three or four days, and eventually turn east. Its projected path would keep it away from the North American coast but it was too soon to rule out a hit.

"Five- to 10-day forecasts are prone to large errors, and it is too early to be highly confident that Igor will miss hitting the U.S. or Canadian coasts," veteran forecaster Jeff Masters said on his Weather Underground blog.

Igor's strength could fluctuate in the next couple of days but it was expected to remain a dangerous hurricane through Thursday, the hurricane center forecasters said.

Igor was expected to weaken before nearing the British territory of Bermuda on Saturday.

Ocean swells generated by Igor will begin affecting the Leeward Islands on Tuesday and will reach Puerto Rico and the Virgin Islands late on Tuesday and Wednesday, causing life-threatening surf and rip current conditions, the hurricane center said.

Computer models kept both storms in the Atlantic and far away from the Gulf of Mexico, where U.S. oil and gas operations are clustered.

Most forecasters predicted the 2010 Atlantic hurricane season would be extremely active. The season runs from June through November and has already brought 10 tropical storms, with five growing into hurricanes. Three of those -- Danielle, Earl and Igor -- have reached Category 4 strength.

"We already had a full season's worth of activity, with about 45 percent of the season still to come," Masters said.