At 0500 GMT, Julia was swirling about 535 kilometres (330 miles) west of the Cape Verde islands, packing sustained winds of 120 kph (75 mph), making it a category one system, the NHC said. The storm "is moving west-northwest near 19 kph (12 mph)," the center said in a statement, warning "some additional strengthening is forecast during the next day or so." The storm was not close to any land mass for now, the NHC noted.

Powerful Hurricane Igor meanwhile swirled in the Atlantic away from land but heading west, while authorities in Haiti prepared evacuations as a smaller separate system formed, that also could threaten Cuba and Mexico's Yucatan peninsula.

Igor, a powerful category four hurricane, was not expected to hit land directly and was forecast to pass some 750 miles (1,200 kilometers) northeast of the island of Hispaniola -- which Haiti and the Dominican Republic share -- by Thursday.

Still, Igor is so powerful that "swells generated by Igor will begin affecting the Leeward islands today (Tuesday) and will reach Puerto Rico and the Virgin Islands tonight and Wednesday. These swells are likely to cause life-threatening surf and rip current conditions."

Of more immediate danger to Haiti, and possibly western Cuba and part of Mexico, was a small system of storms that formed just south-west of Hispaniola, too weak to form a tropical storm but still capable of unleashing "life-threatening flash floods and mudslides," the Miami-based center said.

There was only a 40 percent chance the system could strengthen to tropical storm status, but heavy rain was expected over parts of Hispaniola, Cuba, Jamaica, the Cayman Islands and the Yucatan peninsula over the next two days, the NHC said.

In Haiti, civil defense officials on Monday issued an "orange alert" warning.

Early this week, powerful Tropical Storm Hermine slammed into far northeastern Mexico and then barreled into US territory, sparking flash floods on both sides of the border.

[ YAHOO NEWS ]