A tropical storm is expected to form in the Gulf of Mexico on Friday, putting 7 million Americans under warnings for heavy winds and rain.
After it forms and gains the official name Claudette, the storm will hit the Louisiana coastline Friday night, according to the National Hurricane Center's latest update.
"Landfall is expected later tonight, with the center moving near or over New Orleans on Saturday morning," said CNN meteorologist Dave Hennen.
By 11 a.m. EST Friday, heavy rainfall and wind gusts were beginning to reach portions of the northern Gulf Coast, the center said.
Louisiana, hit hard by heavy rain and flooding last month, is under a state of emergency.
The storm is forecast to hit Alabama, Mississippi, Georgia, Louisiana and the Florida Panhandle through the weekend, according to CNN meteorologist Robert Shackelford.
Tropical storm warnings extend from Louisiana into the Florida Panhandle, affecting cities like New Orleans; Gulfport and Biloxi, Mississippi; Mobile, Alabama; and Pensacola, Florida.
Most of the heavy rain and wind will be east of where the center hits land. So eastern Louisiana, Alabama and Georgia will bear the worst of the storm, forecasters say.
Widespread flash flooding will be the main threat in the Southeast.
Hennen said 14 million people are under flash flood watches from Louisiana to Georgia, including New Orleans; Birmingham, Alabama; and Atlanta.
Rainfall on the already saturated ground could be more than a foot in some areas.
Louisiana activates crisis action team
The storm is expected to make landfall along the Louisiana coastline Friday overnight into Saturday morning.
After landfall, the storm will weaken and head to the northeast, hitting Montgomery, Alabama; Atlanta, Georgia, and Columbia, South Carolina, Shackelford predicted.
The oil company Chevron Corp. said it has pulled non-essential workers from some Gulf of Mexico offshore operations ahead of the potential tropical weather.
"In preparation for the tropical weather, we have transported all non-essential personnel from our Chevron-operated Big Foot, Jack / St. Malo, and Tahiti platforms. All personnel on our Genesis facility have also been moved onshore," Chevron spokesperson Tyler Kruzich told CNN in a statement.
Louisiana Gov. John Bel Edwards released a statement Thursday, saying, "The Governor's Office of Homeland Security and Emergency Preparedness (GOHSEP) has activated its Crisis Action Team and stands ready to support our local partners with any emergency resources needed beyond parish capabilities."
Last month, at least four people died when torrential rain flooded parts of the state.
CNN's Jamiel Lynch contributed to this report.