Updated at 1 p.m. ET
Tropical Storm Gordon will likely strengthen into a hurricane before hitting the northern U.S. Gulf Coast on Tuesday night, forecasters say, urging people along the coast from Louisiana to Florida to be wary of a dangerous storm surge and flash floods.
Gordon's eye was heading toward an area around Gulfport, Miss., the National Hurricane Center said in its 11 a.m. ET update. The storm was moving at 15 mph, some 145 miles east-southeast of the mouth of the Mississippi River.
On Tuesday morning, Gordon was packing maximum sustained winds of 65 mph — short of the 74-mph threshold for a hurricane. A hurricane watch was in effect for the area from the Mississippi-Louisiana border to the Alabama-Florida border.
When Gordon makes landfall, a storm surge of 3-5 feet is possible for all of coastal Mississippi and from Shell Beach in eastern Louisiana to Dauphin Island, Ala., the hurricane center says.
"The deepest water will occur along the immediate coast near and to the east of the landfall location, where the surge will be accompanied by large waves," according to NHC meteorologist Richard Pasch.
The storm's turbulent center is expected to plow a path from the southwest corner of Alabama and central Mississippi into part of Louisiana and southern Arkansas.
Louisiana Gov. John Bel Edwards, Mississippi Gov. Phil Bryant and Alabama Gov. Kay Ivey all declared emergencies in their respective states to free up personnel and equipment ahead of the storm.
Early Tuesday, Gordon was moving west-northwest at 17 mph, the National Hurricane Center said.
Although the storm is expected to become a low-level hurricane by the time it arrives at the north-central Gulf Coast, it will rapidly lose force after making landfall. But forecasters warn that flash floods could be triggered by heavy rainfall from the western Florida Panhandle to Louisiana, with 4-8 inches predicted in many areas. Isolated areas could see up to 12 inches of rain, the weather service says.
Gordon is expected to slow its forward motion as it nears the coast, possibly adding to its rainfall totals in the region.
The third hurricane of the Atlantic season developed on Tuesday, after Florence's winds strengthened to top 75 mph out in the open ocean. The storm doesn't pose a threat to land through the weekend, and it could lose strength late this week, the National Hurricane Center says.