MIAMI (AP) — Tropical Storm Ida has formed in the Caribbean and forecasters say it's aimed at the U.S. Gulf Coast, prompting Louisiana's governor to declare a state of emergency and forecasters to announce a hurricane watch for New Orleans.

The governor says all the state's coastline is in the storm's forecast cone and says it could arrive as a major hurricane.

The U.S. National Hurricane Center says Ida is expected to cross western Cuba as a tropical storm starting Friday afternoon and then strengthen, reaching the Gulf Coast by Sunday.

“Tropical storm conditions are likely in portions of the Cayman Islands tonight and western Cuba Friday and Friday night, with dangerous storm surge possible in portions of western Cuba, including the Isle of Youth, in areas of onshore flow,” wrote the NHC in an advisory Thursday.

The NHC says the storm system is also expected to produce life-threatening heavy rains, flash flooding, and mudslides across Jamaica, the Cayman Islands, western Cuba, and portions of the Yucatan Peninsula.

It says there's an increasing risk of life-threatening storm surge, damaging hurricane-force winds.

The National Weather Service in Miami said Thursday that Tropical Storm Ida had maximum sustained winds of 40 mph.

“This system is forecast to approach the northern Gulf Coast at or near major hurricane intensity on Sunday, although the forecast uncertainty is larger than usual since the system is just forming,” wrote the NHC.

Officials say there is a risk of life-threatening storm surge, damaging hurricane-force winds, and heavy rainfall Sunday and Monday along the northern Gulf Coast from the Florida Panhandle to the upper Texas coast, with the greatest risk along the coast of Louisiana.

Those in these areas should closely monitor the progress of this system and ensure they have their hurricane plans in place, the NHC warns.

SAN JUAN —

Officials in St. Vincent and the Grenadines warned people to plan for possible evacuations as the tiny islands hit recently by massive volcanic eruptions prepared for potential flooding and landslides from Tropical Storm Elsa, which whirled toward the eastern Caribbean on Thursday.

Elsa is the earliest fifth named storm on record, beating out last year's Eduardo which formed on July 6, according to Colorado State University hurricane researcher Phil Klotzbach.

The storm was located about 345 miles east-southeast of Barbados and is expected to pass near or over portions of the Windward Islands or the southern Leeward Islands on Friday. It had maximum sustained winds of 45 mph and was moving west-northwest at 28 mph, according to the National Hurricane Center in Miami.

Tropical storm warnings have been issued for Barbados, Martinique, St. Lucia and St. Vincent and the Grenadines. A tropical storm watch was in effect for Grenada, the southern and western coasts of Haiti, part of the southern coast of the Dominican Republic and Jamaica.

The government of Barbados said it was suspending public transportation and closing vaccination sites and businesses including gas stations by Thursday night, while St. Vincent expected to so by Friday morning.

Elsa was expected to strengthen in upcoming days and move into the eastern Caribbean Sea late Friday and Friday night, and pass near the southern coast of Hispaniola, which is shared by Haiti and the Dominican Republic, on Saturday. The storm was then expected to move near Jamaica and portions of eastern Cuba on Sunday, though the forecast so far calls for it to remain below hurricane force.

The storm was forecast to produce rainfall totals of 3 to 6 inches with maximum totals of 8 inches inches on Friday across the Windward and southern Leeward Islands, including Barbados. The rain could unleash isolated flash flooding and mudslides.

Additional strengthening is forecast for the next few days.

A Tropical Storm Warning is in effect for:

• Barbados
• Martinique
• St. Lucia
• St. Vincent and the Grenadines

A Tropical Storm Watch is in effect for:

• Grenada and its dependencies
• The southern and western coasts of Haiti from the southern border of the Dominican Republic to Môle-Saint-Nicolas.

A warning means that tropical storm conditions are expected somewhere within the warning area within 36 hours. A watch means that tropical storm conditions are possible within the watch area.