Tuesday, August 28, 2012

It's now Hurricane Isaac as New Orleans hunkers down

TODAY's Al Roker reports from New Orleans where Tropical Storm Isaac is expected to make landfall as a Category 1 hurricane and bring a storm surge of between 6 and 12 feet.

By Miguel Llanos, NBC News

Updated at 12:20 p.m. ET: Isaac finally reached hurricane strength on Tuesday, closing in on the Louisiana-Mississippi coast as a slow-moving giant of a system expected to make landfall Tuesday night or early Wednesday.

President Barack Obama added his voice to those of local officials urging residents to hunker down or evacuate if told to do so. "Now's not the time to tempt fate," he said in brief comments. "Listen to your local officials and follow their directions, including if they tell you to evacuate."

At 12:20 p.m. ET, Isaac had 75 mph sustained winds, a mile above the speed needed for a Category 1 hurricane. 

National Hurricane Center Director Rick Knabb said "rain bands will become more frequent and more potent" along the northern Gulf of Mexico coast as the day goes on.

Isaac is very wide as storms go, with tropical storm-force winds stretching 205 miles from its center.


Its size and slow motion, Knabb said, will make for a large storm surge, especially in southeast Louisiana where surges up to 12 feet are predicted.

The fact that a tropical storm's winds move counterclockwise will make matters worse, especially for New Orleans if Isaac makes landfall to the west of the city as some models suggest.

"That counterclockwise direction is really a big problem," NBC meteorologist Al Roker said Tuesday on TODAY. "As it continues to bring in those winds from the southeast it's going to be piling water up."

Rainfall of 7-14 inches across the coast as well as inland is likely, and a few places could even see 20 inches, Knabb said.

NBC's Lester Holt takes a look at how the legacy of Katrina has residents fleeing for higher ground as Tropical Storm Isaac heads for New Orleans, La. Meanwhile, officials say stronger and higher defenses built since Katrina will hold.

Residents should expect "a lot of hazards to contend with, even isolated tornadoes" are possible Tuesday and into Wednesday, Knabb said.

At 12:20 p.m. ET, the center of the storm was located about 75 miles south-southeast of the mouth of the Mississippi River. 

Related: Follow Isaac's path with our storm tracker

It was moving to the northwest at 10 mph and could impact New Orleans seven years to the day that Hurricane Katrina struck on Aug. 29, 2005, killing more than 1,800 people and causing billions of dollars of damage. 

Mandatory evacuations were issued Monday for unprotected, low-lying areas outside New Orleans, as well as low-lying areas in Mississippi.

New Orleans' levees built or repaired after Katrina are designed to withstand far more than that 12-foot surge, in some cases storm surge as high as 26 feet.

In Bay St. Louis, Miss., folks in low-lying areas evacuated while folks on high ground were keeping an eye on Isaac, resident Ellis Anderson told NBC News.

"It's not expected to be another Katrina," she said, "But everybody is watching it very seriously" because of the potential path that could push water into the area hard hit by Katrina and Hurricane Gustav in 2008.

Gustav "went to the west of New Orleans," she recalled, pushing "all that water into that cup that is the Gulf Coast of Mississippi. ... We were getting beaten up and we had a lot of homes that were flooded."

From weather.com: Live updates and analysis

Isaac killed at least 22 people and caused significant flooding and damage in Haiti and the Dominican Republic before skirting the southern tip of Florida on Sunday.

The storm was forecast to strengthen into a Category 1 hurricane, the lowest on the five-step Saffir-Simpson scale of hurricane intensity, with top winds of 90 miles per hour.

While that would be well below the intensity of Katrina, a powerful Category 3 storm on landfall, the vast size of Isaac's slow-moving system has forecasters predicting widespread flooding. 

Alan Diaz / AP

Tropical Storm Isaac drenches multiple countries as it moves toward Louisiana.

Residents in coastal communities from Louisiana to Mississippi stocked up on food and water and tried to secure their homes, cars and boats. 

In New Orleans, a bumper-to-bumper stream of vehicles left the city Monday on a highway toward Baton Rouge in search of higher ground. Others prepared, or were forced, to ride the storm out.

Related: Isaac tests Gulf oil spill defenses
Related: Bad memories return to New Orleans
Related: South hopes for drought relief from Isaac

Along Canal Street in New Orleans' historic French Quarter, crews boarded up the windows of some stores and businesses. 

Reuters and The Associated Press contributed to this report. 

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