MIAMI — A storm moving slowly through the Caribbean Sea is threatening to bring heavy rain, mudslides, and flash floods to parts of Mexico, Cuba, Florida and the U.S. Gulf Coast this weekend.

Subtropical Storm Alberto — the first named storm of the 2018 hurricane season — was roiling parts of coastal Mexico and Cuba with rip currents and dangerous surf on Friday. Both countries issued tropical storm watches for portions of their coastlines, with rain totals in some isolated areas of up to 25 inches.

U.S. forecasters followed suit by issuing a tropical storm watch for parts of the Gulf Coast from the Florida Panhandle southwest of Tallahassee to the New Orleans metropolitan area.

Officials in Northwest Florida are closely monitoring the storm, but no special preparations had been made as of Friday afternoon.

"We're still monitoring at this point," Santa Rosa County Public Information Officer Brandi Whitehurt said. "It will probably be (Saturday) before we make any additional decisions."

Local government offices in Santa Rosa, Okaloosa and Walton counties already are closed Monday for the Memorial Day holiday. Events including the Milton Memorial Day Ceremony and the ceremony at Navarre Park have been canceled. Santa Rosa County will decide whether or not to close the Santa Rosa County Landfill on Saturday, Whitehurst said.

The Gulf Islands National Seashore have closed the following areas because of the storm:


Fort Pickens Area: Last entry at noon Saturday; all visitors must leave by 5 p.m.
Fort Pickens Campground: Mandatory evacuation will begin at noon Saturday; all campers must evacuate by 5 p.m.
Opal Beach Cluster: Last entry at noon Saturday; all visitors must leave by 5 p.m.
Perdido Key Area will be closed to all visitor use and access at 5 p.m. Saturday
Okaloosa Area will be closed at noon Saturday
Naval Live Oaks and Fort Barrancas Areas will close at normal times Saturday

Okaloosa County is on alert and will continue to monitor the storm, according to Public Information Officer Christopher Saul.

The same is true in Walton County.

"There's really no changes right now," Emergency Management Director Jeff Goldberg said. "We're still predicting the same amount of rain. They're looking at it taking a westerly track once it gets into the Gulf, so as long as it keeps up with that, we'll just be doing some preparedness messaging and setting up some updates."

At 7 p.m. CDT, the National Hurricane Center in Miami said Alberto was centered about 100 miles south-southeast of Cozumel, Mexico. Its top sustained winds were 40 mph. A gradual strengthening was expected through the weekend as it moves north.

The United States was expected to start feeling Alberto's effects Saturday. The Hurricane Center said up to 12 inches of rain was possible across the Florida Keys and southern and southwestern Florida. Residents in the storm's expected path were advised to monitor its progress.

"Flooding potential will increase across this region early next week as Alberto is forecast to slow down after it moves inland," the Hurricane Center said.

The National Weather Service said a flash flood watch would be in effect from Saturday evening through Tuesday evening for southeastern Mississippi, southwestern Alabama, and the western Florida Panhandle. A storm surge watch was also issued for parts of Florida, Alabama, Mississippi and Louisiana.

A subtropical storm has a less defined and cooler center than a tropical storm, and its strongest winds are found farther from its center. Subtropical storms can develop into tropical storms, which in turn can strengthen into hurricanes. Alberto comes ahead of schedule; the six-month hurricane season doesn't begin until June 1.

Parts of Florida, Georgia, Alabama, Mississippi and Louisiana have already seen heavy rain this week, and further deluges could leave those areas vulnerable to flash flooding and river flooding. Some beachfront and riverfront communities are already handing out sandbags.

The downpours could dampen Memorial Day, the unofficial start of the summer tourist season along Gulf beaches. Along with heavy rains and high winds come rough seas and a threat of rip currents from Florida to Louisiana that can sweep swimmers out to sea.

Red flags warning of dangerous surf conditions were already flying along some beaches. Jordan Sawmiller of Ohio told WALA-TV that he was approaching the water with caution in Gulf Shores, Alabama.

"It will hit you pretty hard and it sucks you right back out. So, I don't like getting in there very far," Sawmiller said.

Hotel owner Julie Hilton in Panama City Beach told the Panama City News Herald that her family's five hotels are normally full on Memorial Day weekend. But she said people are canceling because of the weather and room reservations are down about 20 percent.

Heavy rain could also be bad news for farmers. Georgia Peanut Commission Chairman and farmer Armond Morris and Tyron Spearman with the National Peanut Buying Points Association inspected a south Georgia peanut field Thursday. They told WALB-TV that farmers are worried about already-soaked young plants.

"Just hopeful that all the peanut stands will be OK, but we may have to replant some peanuts," Morris said.

Only 65 percent of the 2018 Georgia peanut crop has been planted.

"The crop is not growing as well as it should be," said University of Georgia Tifton peanut agronomist Scott Monfort. "So we are getting some cases of yellow peanuts just not growing."