The National Hurricane Center said the powerful storm came ashore late Tuesday, bringing sustained winds of 130 kilometers per hour.  Forecasters also warned of dangerous storm surges along the northern U.S. Gulf Coast.

Earlier Tuesday, President Barack Obama urged residents to get out of the way, if they can.

"We are dealing with a big storm and there could be significant flooding and other damage across a large area. Now is not the time to tempt fate. Now is not the time to dismiss official warnings," said President Obama.

Earlier, forecasters reported flooding along low-lying areas along the coast.  They said some parts of Louisiana could see surges as high as three to four meters.

New Orleans Louisiana Mayor Mitch Landrieu has been preparing his city for a possible direct hit.

''We have dodged a bullet in the sense that this is not a category three storm but a category one; at this strength from 85 to 100 mph winds with 125 mph gusts is plenty big enough to put a big hurt on you if you fall into complacency," said Landrieu.

Forecasters say the slow-moving storm is bringing heavy rains and maximum sustained winds of about 130 kilometers an hour.  It could make landfall late Tuesday or early Wednesday.

The president has declared states of emergency for Louisiana and Mississippi. That declaration opens the door for federal funding, almost seven years to the day that Hurricane Katrina slammed into the region, causing massive damage.

VOA correspondent Brian Padden, in New Orleans, says many people already have left.   

"I had a chance to drive throughout the city. I have been driving throughout the lower ninth ward. It is basically a ghost town [deserted] right now," said Padden. "Sheltered in their house or have been self-evacuated."

CategoryWind SpeedPotential Damage

1119-153 kilometers/hourVery dangerous winds will produce some damage

2154-177 kilometers/hourExtremely dangerous winds. Extensive  damage

3178-208 kilometers/ hourDevastating damage will occur

4209 -251 kilometers/ hourCatastrophic damage will occur

5252 kilometers/hour or higherCatastrophic damage

New Orleans officials are telling residents to be prepared to live without regular water or power supplies for several days.  But not everyone is ready to leave.

Jennifer Landix in the city's Lower 9th Ward is one of those staying put.

"We'll probably get some street flooding from the rain, but you know, heavy winds and stuff, the lights may go out, but we're prepared for all of that. I'm not really in the mood for leaving, let's just put it that way," said Landix.

Experts say the storm could test New Orleans' upgraded flood control and levee systems, which were put in place after Hurricane Katrina left 1,800 people dead in 2005.  Wednesday marks Katrina's seventh anniversary.

Isaac battered eastern Cuba Saturday, after killing at least 19 people in Haiti, which is still recovering from a devastating 2010 earthquake. Two people were killed in the Dominican Republic.  There were no reports of fatalities in Cuba.