Hurricane Irene strengthened into a Category 3 hurricane Wednesday morning as it pounded the Bahamas and showed signs of intensification.
Irene was briefly downgraded to a Category 1 storm overnight when winds dipped below 96 mph. But it quickly restrengthened into a major hurricane Wednesday morning, with sustained winds of more than 115 mph.
A Category 3 storm, or major hurricane, has winds of 111 mph or more.
The hurricane churned over the Bahamas on Wednesday morning about 400 miles southeast of Nassau with wind speeds nearing 110 mph, according to the National Hurricane Center.
The storm is expected to strengthen as it moves west-northwest toward the East Coast of the United States, NHC forecasters said.
Although Irene is expected to face some wind shear along the way, that is not expected to hamper the storm's growth.
Hurricane experts said the storm is not expected to hit Florida. The east coast of the state could experience tropical storm-strength winds, riptides, shore erosion and rain from a storm whose center is expected to be about 150 miles offshore.
Flash flooding and power outage warnings have been issued along the east coast from Florida to Maine.
As computer models continue to shift Irene's path east, it remains uncertain where, or if, Irene will make landfall in the United States this weekend.
Should it hit the East Coast, Irene likely will do so as a Category 4 hurricane, with winds between 131 and 155 mph, experts warned.
In North Carolina, where some forecasters predict the hurricane could make U.S. landfall, tourists on Ocracoke Island, accessible only by boat, have been asked to evacuate.
One woman was killed in Puerto Rico, where Irene left more than 500,000 people without power Monday, according to news reports.