Tropical Storm Dorian passed by Barbados late Monday and could move toward Puerto Rico by late Wednesday. A tropical storm watch was issued for Puerto Rico, according to the National Weather Service. The center of Dorian is expected to move near or over the Windward Islands on Monday night and move into the eastern Caribbean Sea on Tuesday.

The U.S. National Hurricane Center (NHC) in Miami described the fourth tropical storm of the season as a "small tropical cyclone" but said Dorian was expected to intensify to near hurricane strength by the time it passes the Windward Islands. The storm is forecast to be a low-grade Category 1 hurricane by the time it moves near Puerto Rico.

As of 11 p.m. ET Monday, Dorian's maximum sustained winds have slightly decreased to 55 mph. To be classified as a hurricane, the storm must have sustained winds of at least 74 mph.

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Dorian's center was located about 95 miles east-southeast of St. Lucia and was moving west-northwest at about 13 mph. Tropical-storm-force winds extended outward up to 45 miles from the center of the storm. NHC said a wind gust of 55 mph was reported in Barbados late Monday.

A look at the possible tropical-storm-force wind speed possibilities as predicted by the National Weather Service as of Mon., Aug. 26, 2019.

A tropical storm warning was in effect for Barbados, Martinique, St. Vincent and the Grenadines. A tropical storm watch was in effect for Dominica, Saba, St. Eustatius, Grenada and its dependencies. NHC expects tropical storm conditions to appear in the watch areas by Monday night or early Tuesday morning.

A tropical storm warning means tropical storm conditions are expected within 36 hours while a tropical storm watch means tropical storm conditions are possible within 48 hours.

Dorian is expected to drop 3 to 8 inches of rain across the Windward Islands, Martinique and St. Vincent. Isolated areas across the northern Windward Islands could possibly see 10 inches.

The National Weather Service said, "While uncertainty is high, wind and rain impacts are possible in the Bahamas and Florida later this week and weekend."

Tropical Storm #Dorian is passing Barbados. Here are the 11 pm AST Key Messages. pic.twitter.com/ia3dVAO3Gc — National Hurricane Center (@NHC_Atlantic) August 27, 2019

Preparing for Tropical Storm Dorian

In St. Lucia, Prime Minister Allen Chastanet announced that everything on the island of nearly 179,000 people would shut down by 6 p.m. ET on Monday, with the hurricane expected to hit around 2 a.m. EDT on Tuesday.

"We are expecting the worst," he said.

Some were still boarding up windows and buying food and water, but not Joannes Lamontagne, who lives in the island's southwest region. He said by phone that everything at his hotel, Serenity Escape, was already protected.

"I don't wait until it's announced," he said of the storm. "We're always prepared no matter what."

Residents stand in line at a grocery store as they prepare for the arrival of Tropical Storm Dorian, in Bridgetown, Barbados, Monday, Aug. 26, 2019. AP

Meanwhile, in Barbados, many of the 285,000 inhabitants heeded the government's warning, including Fitz Bostic, owner of Rest Haven Beach Cottages. He said he's prepared in case officials shut down power and utility services as they have in previous storms.

"We have to be very cautious," he said in a telephone interview. "The word 'storm' frightens me man. I'm very nervous."

In the U.S. territory of Puerto Rico, hundreds of people have been crowding into grocery stores and gas stations to prepare for Dorian, buying food, water and generators, among other things. Many are worried about power outages and heavy rains on an island still struggling to recover from Hurricane Maria, a Category 4 storm that hit in September 2017. Some 30,000 homes still have blue tarps as roofs and the electrical grid remains fragile and prone to outages even during brief rain showers.

Forecasters said the storm could pass near or south of Puerto Rico on Wednesday and approach the Dominican Republic on Wednesday night.

On Monday, Puerto Rico Gov. Wanda Vázquez signed an executive order declaring a state of emergency and provided a list of all the new equipment that public agencies have bought since Hurricane Maria.

"I want everyone to feel calm," she said. "Agency directors have prepared for the last two years. The experience of Maria has been a great lesson for everyone."

She said public schools will close Tuesday afternoon and that at least one cruise ship canceled its trip to Puerto Rico. She said those without a proper roof can stay in one of the 360 shelters around the island.