Isaac is sweeping up the Gulf Coast just in time for the seventh anniversary of Hurricane Katrina, which devastated New Orleans.
Hurricane Isaac could prove punishing, but it's nowhere near as powerful as Hurricane Katrina, which struck on Aug. 29, 2005.
At one point, Katrina reached Category 5 status with winds over 157 mph. It made landfall as a Category 3 with a huge storm surge. Levee failures caused catastrophic flooding.
This time, Federal Emergency Management Agency officials say the updated levees around New Orleans are equipped to handle storms stronger than Isaac. City officials had no plans to order evacuations, instead telling residents to hunker down and make do with the supplies they have.
Isaac promises a soaking but not much more for Tampa, Fla., where the Republican National Convention was pushed back a day just in case.
Meanwhile in Washington, President Barack Obama says residents of the Gulf Coast should listen to local authorities and follow their directions as Isaac approaches.
In brief remarks from the White House, Obama said, "we are dealing with a big storm" that could cause significant flooding and other damage.
Obama told Gulf Coast residents, "Now is not the time to tempt fate. Now is not the time to dismiss official warnings. You need to take this seriously."
Obama made the comments just before departing on a three-state campaign trip. The White House is aiming to balance leadership on the storm with the president's campaign plans.
Despite stormy conditions, the Republican National Convention moves ahead in Tampa, Fla., with the first full day of party events.