Tropical Storm Gordon is expected to make landfall as a Category 1 hurricane along the north-central Gulf Coast this Tuesday evening, forecasts say.

The storm will bring heavy rainfall across a broad swath of the southern U.S. over the next few days, which could trigger "life-threatening" flash flooding, the National Weather Service said.

The governors of Alabama, Louisiana and Mississippi have each declared a state of emergency ahead of Gordon's expected landfall.

Gordon could be the first hurricane to threaten the continental U.S. this year. Hurricane Lane, which was downgraded to a tropical storm, battered Hawaii with torrential rains last month.

Gordon is expected to produce as much as 8 inches of rain over the western Florida Panhandle, southwest Alabama, southern and central Mississippi, southeastern and northeastern Louisiana and southern Arkansas, with isolated maximum amounts of 12 inches through late Thursday, the National Hurricane Center (NHC) warned.

The combination of a dangerous storm surge and the tide could cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline, NHC noted. The region between Dauphin Island, Alabama to Shell Beach, Louisiana could see water levels 3 to 5 feet above ground.

"Water is going to be a big part of the story," NHC director Ken Graham said in a Facebook video early Tuesday.

The Federal Emergency Management Agency also advised on Tuesday that "Gordon will affect more than just coastal areas; many locations inland will see heavy rainfall."

Gordon first took form as a tropical storm as it passed over the Florida Keys early Monday.

By the time it makes landfall on the Gulf Coast, Gordon will likely be near Category 1 hurricane strength, AccuWeather reported. Category 1 hurricanes have maximum sustained winds of at least 74 mph.

"Fast movement and wind shear should limit the intensity of Gordon, but the storm will be monitored closely as the water is quite warm," explained AccuWeather Senior Meteorologist Alex Sosnowski.