Though Hurricane Irene has weakened slightly and its projected track has been nudged east just a bit, it’s still headed for what could be a devastating collision with the East Coast of the U.S. that will affect tens of millions of people from North Carolina to New England over the weekend.

According to the latest advisory from the National Hurricane Center, Irene is now a Category 2 hurricane (meaning its winds are between 96 and 110 mph). That means it has weakened slightly since this time Thursday, when it was a Category 3.

But, the Hurricane Center warns, “Irene is expected to be near the Category 2/3 boundary when it reaches the vicinity of [North Carolina’s] Outer Banks” very early on Saturday. From there, it will head north along the coast and is likely to take “dead aim” on New York City on Sunday. Mayor Michael Bloomberg has said he may order a mandatory evacuation of the city’s low-lying areas, including parts of lower Manhattan.

Utilities, such as the Washington area’s Pepco, are “already warning customers that they could be without power for some time,” The Washington Post reports.

We will be following developments through the weekend.

Update at 1:55 p.m. ET. New York orders evacuations of low-lying areas:

Mayor Michael Bloomberg just announced that his office has issued a “mandatory evacuation order for all New Yorkers who live in low-lying areas.” They’re to be out of the areas by 5 p.m. ET Saturday. The mayor’s office has posted a pdf of “New York City hurricane evacuation zones” here.

Update at noon ET: “Obama: ‘Don’t Wait, Don’t Delay’ If You’re In Irene’s Path.”

Update at 11:30 a.m. ET. Latest Outlook; Bad News And Not-So-Bad News:

In its 11 a.m. ET advisory the Hurricane Center says it has extended the “hurricane warning” for the Chesapeake Bay north about 30 miles. Earlier, the warning area went as far as Smith Point. Now it goes to Drum Point.

But the Center’s guidance is also slightly less ominous in one way.

At 8 a.m. ET it wrote that “Irene is a Category 2 hurricane … some re-intensification is possible today … and Irene is expected to be near the threshold between Category 2 and 3 as it reaches the North Carolina coast.”

At 11 a.m. ET, it wrote that “Irene is a Category 2 hurricane … [and] little change in strength is forecast before Irene reaches the coast of North Carolina.”

The differences between categories are outlined here. Category 2 hurricanes have maximum sustained winds of 96-110 mph. Category 3 hurricanes have maximum sustained winds of 111-130 mph.

As of 11 a.m. ET, Irene’s winds were maxing out at 105 mph.

Update at 9:40 a.m. ET. Rain Is Falling On The Carolinas.

North Carolina’s News & Observer writes that:

“Hurricane Irene’s rains began reaching the U.S. East Coast on Friday. … Rain began falling along the coasts of North and South Carolina as Irene trudged toward the coast from the Bahamas.

“Swells from the hurricane and 6 to 9-foot waves were showing up in North Carolina’s Outer Banks early Friday and winds were expected to begin picking up later in the day, said Hal Austin, a meteorologist with the National Weather Service.”

Update at 9:10 a.m. ET. “Dangerous” Storm Surges Expected.

From the latest Hurricane Center advisory:

“An extremely dangerous storm surge will raise water levels by as much as 6 to 11 feet above ground level in the hurricane warning area in North Carolina … including the Albemarle and Pamlico sounds. Storm surge will raise water levels as much as 4 to 8 feet above ground level over southern portions of the Chesapeake Bay … including tributaries … and the eastern shore of the Delmarva peninsula. Storm surge will raise water levels by as much as 3 to 6 feet above ground level along the Jersey shore. … The surge will be accompanied by large … destructive … and life-threatening waves.”

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