Tropical Storm Isaias forms, is forecast to become a hurricane and hit US Gulf Coast this week

Tropical Storm Isaias formed Wednesday in the warm waters off eastern Mexico and forecasters predicted it will quickly strengthen into the first hurricane of the Atlantic season before striking the U.S. Gulf Coast later in the week.

Communities in Isaias' potential path moved quickly to prepare with landfall forecast as soon as Friday evening. Some Gulf oil wells paused production and an Alabama beach city canceled a weekend festival known to draw thousands of tourists. Florida's governor declared a state of emergency for more than one-third of the state's counties.

Isaias could become a major Category 3 hurricane, with winds of 111 mph (178 kph) or stronger, before it strikes land, said Michael Brennan, director of the U.S. National Hurricane Center.

“We’re expecting multiple dangerous, life-threatening impacts along portions of the northern Gulf Coast beginning Friday and continuing into the weekend," Brennan said in a video briefing Wednesday.

The storm was on track to tie or break a 121-year-old record as the latest arriving initial hurricane of the Atlantic season. According to the National 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 due to a strong El Niño, which disrupts storm formation over that ocean. Storm activity in the Pacific has been above average .

The Miami-based hurricane center on Wednesday issued a hurricane watch for the northern Gulf Coast from Bay St. Louis, Mississippi, to Indian Pass on the Florida Panhandle. The watch means hurricane conditions are possible within 48 hours.

Brennan said dangerous storm surge could affect an even wider area, from southeast Louisiana to Florida's Big Bend. Heavy rains of 3 to 6 inches (7 to 15 centimeters) could trigger flash flooding near the coast, with accumulations of 1 to 3 inches (3 to 8 centimeters) as far inland as Tennessee and the western Carolinas.

Isaias was centered about 255 miles (410 kilometers) northwest of Progreso, Mexico, and about 520 miles (840 kilometers) southwest of the Mississippi River’s mouth, according to the hurricane center. It had maximum sustained winds of 50 mph (85 kph) and was moving east-northeast at 8 mph (13 kph).

Forecasters predict Isaias (pronounced ees-ah-EE’-ahs, according to the hurricane center) will become a hurricane by Thursday as it turns northward toward the U.S. Gulf Coast. Though its path and timing could shift, the storm is expected to make landfall late Friday or early Saturday.

Ahead of the storm, oil and gas producers began shutting down some offshore production in the Gulf, which accounts for almost 15% of crude pumped annually in the U.S.

As of Tuesday, producers had temporarily halted about 9.2% of the oil produced in the region, taking about 185,000 barrels per day off the market, according to the Marine Minerals Administration.

In Gulf Shores, Alabama, the storm threat caused organizers to cancel the National Shrimp Festival that had been scheduled for Thursday through the weekend. The event drew an estimated 325,000 people last year.

Festival Chairman Rob Barnas said the safety of thousands of anticipated visitors, plus hundreds of vendors and volunteers, “was our top priority.”

Florida Gov. Ron DeSantis declared a state of emergency for 25 counties in the Panhandle and Big Bend regions. The declaration activates the state's emergency management plan for hurricanes, allowing officials to deploy disaster responders and equipment.

In Pensacola on the Florida Panhandle, electric utilities were prepositioning crews to quickly repair any power outages. City officials provided sand for residents to fill sandbags to protect their homes against flooding. And Pensacola Mayor D.C. Reeves urged people to check on elderly neighbors and others who might need help.

“Obviously no need to panic at this point," Reeves told a news conference Wednesday. "This is really about preparation.”

Collins reported from Hartford, Connecticut, and Rico reported from Atlanta. Associated Press journalists Russ Bynum in Savannah, Georgia, and Julie Walker in New York contributed to this report.