Last Updated 2:16 p.m. ET
Hurricane Irene cut a destructive path through the Caribbean en route to the United States, where Federal officials warned that the first hurricane to seriously threaten the U.S. in three years could cause flooding and other impacts from Florida to New England.
Craig Fugate, the administrator of the Federal Emergency Management Agency, said people along the entire Eastern Seaboard need to pay attention to Irene.
The U.S. National Hurricane Center in Miami expected Irene to reach Category 3 strength on Tuesday.
"For residents in states that may be affected later this week, it's critical that you take this storm seriously," said Fugate.
Forecasters say the hurricane could grow to a monstrous Category 4 storm with winds of more than 131 mph before it's predicted to come ashore this weekend on the U.S. mainland.
Officials could begin issuing watches for parts of the U.S. mainland later in the day. Because the storm is so large, Florida could begin feeling some effects from the storm late Wednesday.
Current government models have the storm's outer bands sweeping Florida late this week before it takes aim at the Carolinas this weekend, though forecasters caution that predictions made days in advance can be off by hundreds of miles. Georgia is also likely to be affected.
National Hurricane Center director Bill Read said farther north, the Atlantic waters can be warm enough to keep Irene churning as a hurricane. Hurricanes typically can maintain or gain strength over warmer waters.
Forecasters say Hurricane Irene could hit the states of North or South Carolina this weekend and could reach the Washington area by Sunday at hurricane strength.
Irene could disrupt plans to dedicate a memorial to civil rights leader Martin Luther King Jr. in Washington. The dedication is scheduled for Sunday, with up to 250,000 people attending, including President Barack Obama.
Fugate told reporters Tuesday that talks have begun with the National Park Service, which runs the National Mall, about whether to go forward with the dedication ceremony.
Current tracks have Irene making landfall in North Carolina, though such projections are less reliable several days in advance.
For now, the first Atlantic hurricane of the season had maximum sustained winds Tuesday afternoon of near 100 mph and was centered about 55 miles south of Grand Turk Island. Hurricane force winds extend outward up to 50 miles from the center, and tropical storm force winds extend outward up to 205 miles. The hurricane was moving west-northwest near 10 mph.
Irene was forecast to pass over or near the Turks and Caicos Islands and the southeastern Bahamas by Tuesday night and be near the central Bahamas early Wednesday.
Ahead of a possible landfall, communities in Florida were beginning to prepare for the worst, reports CBS News correspondent Bigad Shaban.
"We need to make a decision whether we're going to open up some of our special care facilities - how many shelters we're going to open up," said Palm Beach County's public safety director Vincent Bonvento.
Irene is already being compared to two monster storms of the past that made landfall in North Carolina: Gloria in 1985 and Floyd in 1999, which triggered the third largest evacuation in U.S. history - 2.6 million people in five coastal states, reports Shaban.
The last hurricane to make landfall in the U.S. was Ike, which pounded Texas in 2008.
After several extremely active years, Florida has not been struck by a hurricane since Wilma raked across the state's south in October 2005. That storm was responsible for at least five deaths in the state and came two months after Hurricane Katrina devastated New Orleans.
Irene slashed directly across Puerto Rico, tearing up trees and knocking out power to more than a million people. It then headed out to sea, north of the Dominican Republic, where the powerful storm's outer bands were buffeting the north coast with dangerous sea surge and downpours. President Barack Obama declared an emergency for Puerto Rico, making it eligible for federal help.
Many of the center's computer models had the storm veering northward away from Florida's east coast toward Georgia and the Carolinas. A hurricane center forecast map said the storm's center could come ashore in one of the states on Saturday or Sunday, but forecasters said much was still unclear.
"In terms of where it's going to go, there is still a pretty high level of uncertainty," said Wallace Hogsett, a National Hurricane Center meteorologist. "It's a very difficult forecast in terms of when it's going to turn northward."
In the U.K. territory of the Turks and Caicos, a steady stream of customers bought plywood and nails at hardware stores, while others readied storm shutters and emergency kits at home.
"I can tell you I don't want this storm to come. It looks like it could get bad, so I've definitely got to get my boats out of the water," said Dedrick Handfield at the North Caicos hardware store where he works.
Irene first slashed directly across Puerto Rico, tearing up trees and knocking out power to more than a million people. President Barack Obama declared an emergency for Puerto Rico, making it eligible for federal help.
The hurricane then headed out to sea, north of the Dominican Republic, where the powerful storm's outer bands buffeted the north coast with dangerous sea surge and downpours.
Hundreds were displaced by flooding in the Dominican Republic, forced to take refuge in churches, schools or relatives' homes. Electricity also was cut in some areas.
"Everything filled with water, there was just water everywhere," said Maria Altagracia Fernandez, who spent Monday night sleeping on the floor with her five children and about 100 other people at a shelter in the fishing town of Boba, 135 miles northeast of Santo Domingo.