UPDATE: Isaac makes landfall in New Orleans; networks to air live all night

NEW ORLEANS (AP)

Hurricane Isaac spun into the southern Louisiana coast tonight, sending floodwaters surging and unleashing fierce winds as residents hunkered down behind boarded-up windows.

New Orleans calmly waited out another storm on the eve of Hurricane Katrina’s seventh anniversary, hoping the city’s strengthened levees will hold.

Isaac, a massive storm spanning nearly 200 miles from its center, made landfall at about 6:45 p.m. near the mouth of the Mississippi River.

But it was zeroing in on New Orleans, about 75 miles to the northwest, turning streets famous for all-hours celebrations into ghost boulevards.

The storm drew intense scrutiny because of its timing — just before the anniversary of the hurricane that devastated that city, while the first major speeches of the Republican National Convention went on in Tampa, Fla., already delayed and tempered by the storm.

While many residents stayed put, evacuations were ordered in low-lying areas of Louisiana and Mississippi, where officials closed 12 shorefront casinos.

By late today, more than 100,000 homes and businesses had lost power.

Ed Rappaport, deputy director of the National Hurricane Center, said Isaac’s core would pass west of New Orleans with winds close to 80 mph and head for Baton Rouge.

“On this course, the hurricane will gradually weaken,” Rappaport said tonight from the Miami-based center.

He said gusts could reach about 100 mph at times, especially at higher levels which could damage high-rise buildings in New Orleans.

Some television news networks are planning to stay on live overnight to follow the hurricane and its impact on the Gulf Coast.

CNN, Fox News Channel and The Weather Channel said today they will stay with storm coverage all night.

CNN and Fox usually air reruns of prime-time shows in the wee hours.

MSNBC says it hasn’t made a decision on staying live.

Anderson Cooper is leading CNN’s coverage from New Orleans, with Shepard Smith on Fox. All the news networks have mixed news of the storm in with Republican National Convention coverage.

The convention is taking place in Tampa, Fla., after being delayed by nasty weather.

Forecasters say the slow-moving storm could dump prodigious amounts of rain on the New Orleans area.