Hurricane Isaias is expected to get stronger on its way to Florida, Alabama and Mississippi coasts

Isaias surged toward the U.S. Gulf Coast on Thursday as the first hurricane of the Atlantic season, prompting mandatory evacuations, school closures and local government shutdowns in parts of Florida.

Isaias was forecast to intensify rapidly and bring strong winds and a life-threatening storm surge to the Florida Panhandle, southern Alabama and southern Mississippi when it makes landfall on the northern Gulf Coast late Friday or early Saturday. Heavy rain with the risk of flooding was possible into the weekend as far inland as the Tennessee Valley.

The hurricane had maximum sustained winds around 80 mph (129 kph) and was moving east-northeast at 9 mph (15 kph) early Thursday morning, the National Hurricane Center in Miami said. It was centered about 420 miles (676 kilometers) south-southwest of the mouth of the Mississippi River.

"Preparations to protect life and property from storm surge and damaging winds along the warning area of the Gulf Coast should be rushed to completion today," the center said Thursday.

Coastal communities moved quickly to prepare. Some Gulf oil wells paused production, and at least four Florida school districts canceled classes for later in the week. Okaloosa County announced mandatory evacuations for some coastal areas and communities were closing government offices as of Thursday afternoon. Governors in Florida and Alabama declared a state of emergency for dozens of counties.

Water from the storm surge and high tide could reach heights of 5 to 7 feet (1.5 to 2 meters) in parts of Alabama and Mississippi, the center said. Isaias also could dump up to 10 inches (25 centimeters) of rain along parts of the Gulf Coast and spawn tornadoes Friday night into Saturday from Alabama to the Florida Panhandle to southwestern Georgia. The hurricane itself is expected to quickly weaken after making landfall.

The National Weather Service told communities from Ocean Springs, Mississippi, to Gulf County, Florida, to prepare for the possibility of "long-duration power outages."

Isaias developed more than four months into the Atlantic hurricane season and was short by one day of tying a 121-year-old record for the area's latest-forming hurricane. According to the weather service, the record dates to 1905, when the year's first Atlantic hurricane formed on Oct. 8.

The Atlantic hurricane season has been unusually quiet this year because of a strong El Nino, which disrupts storm formation over that ocean. Storm activity has been above average in the Pacific, where Tropical Storm Simon formed Wednesday off Mexico.

Isaias is expected to strike a swath of coastline that's familiar with major hurricanes.

One of the 20th century's worst storms, Hurricane Camille, killed more than 250 people after hitting land near Waveland, Mississippi, in 1969. Hurricane Katrina in 2005 razed neighborhoods in Mississippi, flooded New Orleans and killed nearly 1,400 people. And Hurricane Michael leveled homes and buildings near Panama City, Florida, in 2018.