Tropical Storm Isaac's plodding pace through the Gulf of Mexico means the slow moving storm could punish coastal areas with up to 36 hours of tropical winds and 10 to 16 inches of rain, Louisiana's Gov. Bobby Jindal warned today.
Isaac, which is packing winds of 65 mph, is expected to strengthen to a Category 1 hurricane with winds of at least 74 mph by the time it reaches land late Tuesday or early Wednesday.
Jindal said the threat that New Orleans would be inundated on the seventh anniversary of the devastating Hurricane Katrina was lessening.
FEMA director Craig Fugate and the National Hurricane Center's Dr. Rick Knabb say there has been too much focus on New Orleans bracing for Isaac on the anniversary of Katrina.
"I think people need to understand this is not a New Orleans storm. This is a Gulf Coast storm," Fugate said today.
Fugate and Jindal warned people in low lying areas to get out of Isaac's way.
"Today is the day," Jindal said. "Today is the final day you should be taking any final precautions. If you want to evacuate, today is the day to do that."
Overnight, 50,000 people had already evacuated from southeast Louisiana's St. Charles parish. In addition, 2,000 jail inmates have been moved out of Isaac's expected path.
Jindal said over 4,000 National Guardsmen will be mobilized in case of emergency, but said he does not anticipate having to activate contraflow highway rules for evacuation purposes.
Jindal said that President Obama called him today to say that the governor's request for a pre-landfall federal disaster declaration had been approved. The approval opens up federal funding to potentially help Louisiana cope with any damage.
"We are going to need help after the storm as well," Jindal said. "This is not going to be done just after the storm makes landfall or even just after the storm leaves Louisiana."
While not packing winds of some stronger hurricanes, Isaac's slow pace means it "could actually cause more damage," the governor said.
He said the storm could batter areas with tropical winds for up to 36 hours and could dump more than a foot of rain while lingering over some areas.
Jindal said he is skipping the Republican National Convention in Florida where he was expected to speak because of Isaac. "I will not be speaking or attending the Republican National Convention in Florida.There is no time for politics here in Louisiana," he said.
Fugate warned that Isaac's biggest punch may land in Alabama or Mississippi. The National Hurricane Center said to expect a storm surge of at least six feet with the possibility it could reach up to 12 feet.
Alabama and Mississippi have already joined Louisiana in declaring states of emergency. A tropical storm warning is in effect along the Texas and Louisiana border.
The storm is currently off the west coast of Florida and is moving in the direction of the northern Gulf Coast.
"We can say that conditions are favorable for it to become a hurricane during the next day or so and after that steady intensification is expected until the center reaches the coast," said Todd Kimberlain, a forecaster at the National Hurricane Center. The storm is no longer predicted to be a Category Two hurricane because of the dry air mixed into the system.
"With winds of that strength, one of the greatest concerns is storm surge, where the water will be moving ashore, blown in by the winds," said Ed Rappaport, forecaster with the National Hurricane Center.
The storm threatened Tampa and the Republican National Convention last week, but moved away from the Florida coast. Overnight, Isaac dumped more than 8 inches of rain on South Florida, flooding many streets.
Nearly 1 million students in Miami-Dade, Broward and Monroe counties remained home Monday with all public and Catholic schools closed.
Isaac Could Reach Hurricane Strength When It Reaches Coast
In Alabama, residents were advised to start evacuating today and Mississippi Governor Phil Bryant is also advising residents to prepare.
"I urge Mississippians to monitor their local media and heed all warnings and evacuation orders issued by local and state officials," he said.
Airlines canceled 857 flights on Sunday, with airports in Miami and Fort Lauderdale canceling 589, according to the flight-tracking service FlightAware. There have already been 235 flight cancellations for today, with 167 in Miami alone.
ABC News' Dean Schabner and Max Golembo, ABC News Radio and The Associated Press contributed to this report.