HUGE WIND FIELD

Pedestrians walk past sandbags used to control possible floods at downtown Manhattan in New York August 26, 2011. New York on Friday ordered residents in low-lying areas to evacuate before the onslaught this weekend of massive Hurricane Irene, which churned northward along the East Coast. [Photo/Agencies]

Irene weakened early on Friday to a Category 2 hurricane from a 3 on the five-step Saffir-Simpson scale but it was still carrying winds of up to 100 mph (155 kph).

It is expected to remain a hurricane as it sweeps up the coast over the weekend. The Miami-based hurricane center said Irene could dip below hurricane strength before reaching New England but its impact would not vary much.

Irene, the first hurricane of the 2011 Atlantic season, already caused as much as $1.1 billion in insured losses in the Caribbean this week, catastrophe modeling company AIR Worldwide said, with more losses expected to come.

The hurricane center said hurricane force winds extended outward up to 90 miles (150 km) from Irene's center, while tropical storm force winds extended out up to 290 miles (465 km), giving the storm a vast wind field width of nearly 600 miles (960 km).

"Tropical storm force winds are expected to begin along the mid-Atlantic coast Saturday morning with hurricane conditions expected by Saturday afternoon," the NHC said in its final advisory Friday night.

"Tropical storm conditions are expected to reach southern New England Saturday night with hurricane conditions expected on Sunday," it said

"WATCHING THAT BIG WHITE SWIRL"

People, who did not evacuate in preparation for Hurricane Irene, ride past an empty beach down a boardwalk in Ocean City, Maryland, August 26, 2011. National Hurricane Center Director Bill Read said Irene, which will be the first significant hurricane to affect the populous Northeast in decades, would lash the Atlantic seaboard with tropical storm-force winds and a "huge swath of rain" from the Carolinas to New England. [Photo/Agencies]

Wall Street firms scrambled to raise cash into early next week in case Irene caused major disruption in trading.

Traders were "watching that big white swirl" on their television sets, said Guy LeBas, chief fixed income strategist at Janney Montgomery Scott in Philadelphia.

Northeast oil, natural gas and power facilities also made preparations.

Brent crude oil futures rose in choppy trading on Friday as the storm approached and traders weighed comments by Federal Reserve Chairman Ben Bernanke on the economy.

Benedict Willis III, director of floor operations for investment banking boutique Sunrise Securities, said the New York Stock Exchange had a responsibility to open on Monday after the storm passes because millions of investors will be relying on it for stock prices.

"But if the waters rise this high," he said, gesturing at the buzzing trading floor, "then it's a bigger problem than I can handle. My name's not Noah."

Irene will be the first hurricane to hit the U.S. mainland since Ike pounded Texas in 2008.

In Washington, Irene forced the postponement of Sunday's dedication ceremony for the new memorial honoring civil rights leader Martin Luther King Jr. Tens of thousands of people, including Obama, had been expected to attend.

Flooding from Irene killed at least one person in Puerto Rico and two in Dominican Republic. The storm knocked out power in the Bahamian capital, Nassau, and blocked roads with trees.