MIAMI (AP) - Forecasters say Isaac has strengthened into a Category 1 hurricane with 75 mph winds as it makes its way toward Louisiana.
The U.S. National Hurricane Center said Tuesday that Isaac gained strength as it moved over the warm, open waters of the Gulf of Mexico.
Isaac is expected to make landfall over southeastern Louisiana, possibly the New Orleans area, either late Tuesday or early Wednesday.
People are filling a municipal auditorium that's been turned into a shelter in the city of Houma, southwest of New Orleans.
One man who's there with his wife and their teenage sons says he rode out hurricanes when he was younger, but that was before he saw the damage from hurricanes Andrew, Katrina and Rita.
Obama tells residents to heed officials on Isaac
WASHINGTON (AP) - President Barack Obama says residents of the Gulf Coast should listen to local authorities and follow their directions as Tropical Storm 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.