Tropical Storm Cindy was slowly churning along the Gulf Coast, bringing copious rainfall that could cause life-threatening flash flooding from Texas to parts of Florida, forecasters said on Wednesday.

Here’s the latest:

What states will be affected?

Alabama, Louisiana, Mississippi, Texas and northwest Florida are expected to feel the effects of the storm, officials said.

A tropical storm warning has been posted along the Gulf Coast from San Luis Pass, Tex., to the Alabama-Florida state line, including metropolitan New Orleans and Lake Pontchartrain in Louisiana. The warning means tropical storm conditions are expected within the next 12 to 24 hours.

When is the worst expected?

Tropical storm conditions were affecting parts of the northern coast of the Gulf of Mexico and should spread west through early Thursday, Dennis Feltgen, a spokesman and meteorologist at the National Hurricane Center, said in an email on Wednesday.

The center of Cindy is expected to approach the coast of southwest Louisiana and southeast Texas on Wednesday late afternoon or night and move inland over southeastern Texas or southwestern Louisiana on Thursday.

How much rain is expected?

Cindy could bring as much as 6 to 9 inches of rain, with isolated maximum amounts of 12 inches over southeastern Louisiana, southern Mississippi, southern Alabama and the Florida Panhandle through Thursday, he wrote.

This rainfall could cause life-threatening flash flooding in these areas.

Rainfall amounts of 3 to 5 inches with isolated maximum amounts of 6 inches can be expected farther west across western Louisiana and eastern Texas through Thursday.

What preparations are being made?

Southern Louisiana and southern Mississippi face the greatest threat of heavy rain and flash flooding, Louisiana Gov. John Bel Edwards said in a statement.

The Louisiana National Guard has moved high-water vehicles and helicopters to be near areas that could flood. The Federal Emergency Management Agency was moving 125,000 meals and 200,000 liters of water into the state, he said.

Jim Waskom, director of the Governor’s Office of Homeland Security and Emergency Preparedness, said some of the rainfall projections are the highest officials have seen since flooding in August in which 13 people died and about 30,000 people had to be rescued.

Mr. Edwards declared a statement of emergency on Wednesday; Gov. Kay Ivey of Alabama issued one on Tuesday because of the flooding threat.

“All arms of the state’s emergency preparedness and response apparatus are taking Tropical Storm Cindy seriously, and we are calling on all Louisianans throughout the state to do so as well,” Mr. Edwards said.

A storm surge of 1 to 3 feet above ground level is expected along the coast in portions of the warning area, with isolated areas possibly up to 4 feet. A few tornadoes are possible this morning through tonight from the western Florida Panhandle to southern Louisiana.

What else is affected?

The storm could disrupt oil supplies at refining and production centers along the Gulf Coast, which could drive up prices for consumers, Reuters reported.

The Louisiana Offshore Oil Port, the largest privately owned crude storage terminal in the United States, suspended vessel offloading operations ahead of the storm, but said it expected no interruptions to deliveries from its hub Louisiana.

Royal Dutch Shell said it was suspending some offshore well operations, but production was so far unaffected, Reuters reported. Anadarko Petroleum said it had evacuated nonessential staff from its Gulf of Mexico facilities.